This is a leftover from the early versions of this function where it could
be invoked without mm::mm_cid::lock held.
Remove it and add lockdep asserts instead.
Fixes: 653fda7ae7 ("sched/mmcid: Switch over to the new mechanism")
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260310202526.116363613@kernel.org
Matthieu and Jiri reported stalls where a task endlessly loops in
mm_get_cid() when scheduling in.
It turned out that the logic which handles vfork()'ed tasks is broken. It
is invoked when the number of tasks associated to a process is smaller than
the number of MMCID users. It then walks the task list to find the
vfork()'ed task, but accounts all the already processed tasks as well.
If that double processing brings the number of to be handled tasks to 0,
the walk stops and the vfork()'ed task's CID is not fixed up. As a
consequence a subsequent schedule in fails to acquire a (transitional) CID
and the machine stalls.
Cure this by removing the accounting condition and make the fixup always
walk the full task list if it could not find the exact number of users in
the process' thread list.
Fixes: fbd0e71dc3 ("sched/mmcid: Provide CID ownership mode fixup functions")
Closes: https://lore.kernel.org/b24ffcb3-09d5-4e48-9070-0b69bc654281@kernel.org
Reported-by: Matthieu Baerts <matttbe@kernel.org>
Reported-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260310202526.048657665@kernel.org
A newly forked task is accounted as MMCID user before the task is visible
in the process' thread list and the global task list. This creates the
following problem:
CPU1 CPU2
fork()
sched_mm_cid_fork(tnew1)
tnew1->mm.mm_cid_users++;
tnew1->mm_cid.cid = getcid()
-> preemption
fork()
sched_mm_cid_fork(tnew2)
tnew2->mm.mm_cid_users++;
// Reaches the per CPU threshold
mm_cid_fixup_tasks_to_cpus()
for_each_other(current, p)
....
As tnew1 is not visible yet, this fails to fix up the already allocated CID
of tnew1. As a consequence a subsequent schedule in might fail to acquire a
(transitional) CID and the machine stalls.
Move the invocation of sched_mm_cid_fork() after the new task becomes
visible in the thread and the task list to prevent this.
This also makes it symmetrical vs. exit() where the task is removed as CID
user before the task is removed from the thread and task lists.
Fixes: fbd0e71dc3 ("sched/mmcid: Provide CID ownership mode fixup functions")
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260310202525.969061974@kernel.org
The trace_clock_jiffies() function that handles the "uptime" clock for
tracing calls jiffies_64_to_clock_t(). This causes the function tracer to
constantly recurse when the tracing clock is set to "uptime". Mark it
notrace to prevent unnecessary recursion when using the "uptime" clock.
Fixes: 58d4e21e50 ("tracing: Fix wraparound problems in "uptime" trace clock")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260306212403.72270bb2@robin
When debug logging is enabled, read_key_from_user_keying() logs the first
8 bytes of the key payload and partially exposes the dm-crypt key. Stop
logging any key bytes.
Link: https://lkml.kernel.org/r/20260227230008.858641-2-thorsten.blum@linux.dev
Fixes: 479e58549b ("crash_dump: store dm crypt keys in kdump reserved memory")
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Baoquan He <bhe@redhat.com>
Cc: Coiby Xu <coxu@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
BPF_ST | BPF_PROBE_MEM32 immediate stores are not handled by
bpf_jit_blind_insn(), allowing user-controlled 32-bit immediates to
survive unblinded into JIT-compiled native code when bpf_jit_harden >= 1.
The root cause is that convert_ctx_accesses() rewrites BPF_ST|BPF_MEM
to BPF_ST|BPF_PROBE_MEM32 for arena pointer stores during verification,
before bpf_jit_blind_constants() runs during JIT compilation. The
blinding switch only matches BPF_ST|BPF_MEM (mode 0x60), not
BPF_ST|BPF_PROBE_MEM32 (mode 0xa0). The instruction falls through
unblinded.
Add BPF_ST|BPF_PROBE_MEM32 cases to bpf_jit_blind_insn() alongside the
existing BPF_ST|BPF_MEM cases. The blinding transformation is identical:
load the blinded immediate into BPF_REG_AX via mov+xor, then convert
the immediate store to a register store (BPF_STX).
The rewritten STX instruction must preserve the BPF_PROBE_MEM32 mode so
the architecture JIT emits the correct arena addressing (R12-based on
x86-64). Cannot use the BPF_STX_MEM() macro here because it hardcodes
BPF_MEM mode; construct the instruction directly instead.
Fixes: 6082b6c328 ("bpf: Recognize addr_space_cast instruction in the verifier.")
Reviewed-by: Puranjay Mohan <puranjay@kernel.org>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Sachin Kumar <xcyfun@protonmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/Y6IT5VvNRchPBLI5D7JZHBzZrU9rb0ycRJPJzJSXGj7kJlX8RJwZFSM2YZjcDxoQKABkxt1T8Os2gi23PYyFuQe6KkZGWVyfz8K5afdy9ak=@protonmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When a register undergoes a BPF_END (byte swap) operation, its scalar
value is mutated in-place. If this register previously shared a scalar ID
with another register (e.g., after an `r1 = r0` assignment), this tie must
be broken.
Currently, the verifier misses resetting `dst_reg->id` to 0 for BPF_END.
Consequently, if a conditional jump checks the swapped register, the
verifier incorrectly propagates the learned bounds to the linked register,
leading to false confidence in the linked register's value and potentially
allowing out-of-bounds memory accesses.
Fix this by explicitly resetting `dst_reg->id` to 0 in the BPF_END case
to break the scalar tie, similar to how BPF_NEG handles it via
`__mark_reg_known`.
Fixes: 9d21199842 ("bpf: Add bitwise tracking for BPF_END")
Closes: https://lore.kernel.org/bpf/AMBPR06MB108683CFEB1CB8D9E02FC95ECF17EA@AMBPR06MB10868.eurprd06.prod.outlook.com/
Link: https://lore.kernel.org/bpf/4be25f7442a52244d0dd1abb47bc6750e57984c9.camel@gmail.com/
Reported-by: Guillaume Laporte <glapt.pro@outlook.com>
Co-developed-by: Tianci Cao <ziye@zju.edu.cn>
Signed-off-by: Tianci Cao <ziye@zju.edu.cn>
Co-developed-by: Shenghao Yuan <shenghaoyuan0928@163.com>
Signed-off-by: Shenghao Yuan <shenghaoyuan0928@163.com>
Signed-off-by: Yazhou Tang <tangyazhou518@outlook.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260304083228.142016-2-tangyazhou@zju.edu.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
If the cpuidle governor .select() callback is skipped because there
is only one idle state in the cpuidle driver, the .reflect() callback
should be skipped as well, at least for consistency (if not for
correctness), so do it.
Fixes: e5c9ffc6ae ("cpuidle: Skip governor when only one idle state is available")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Christian Loehle <christian.loehle@arm.com>
Reviewed-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://patch.msgid.link/12857700.O9o76ZdvQC@rafael.j.wysocki
scx_enable() uses double-checked locking to lazily initialize a static
kthread_worker pointer. The fast path reads helper locklessly:
if (!READ_ONCE(helper)) { // lockless read -- no helper_mutex
The write side initializes helper under helper_mutex, but previously
used a plain assignment:
helper = kthread_run_worker(0, "scx_enable_helper");
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
plain write -- KCSAN data race with READ_ONCE() above
Since READ_ONCE() on the fast path and the plain write on the
initialization path access the same variable without a common lock,
they constitute a data race. KCSAN requires that all sides of a
lock-free access use READ_ONCE()/WRITE_ONCE() consistently.
Use a temporary variable to stage the result of kthread_run_worker(),
and only WRITE_ONCE() into helper after confirming the pointer is
valid. This avoids a window where a concurrent caller on the fast path
could observe an ERR pointer via READ_ONCE(helper) before the error
check completes.
Fixes: b06ccbabe2 ("sched_ext: Fix starvation of scx_enable() under fair-class saturation")
Signed-off-by: zhidao su <suzhidao@xiaomi.com>
Acked-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
permissive for auxiliary clocks, to not reject syscalls
based on the status field that do not try to modify the
status field. This makes ABI behavior in clock_adjtime()
consistent with CLOCK_REALTIME.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'timers-urgent-2026-03-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fix from Ingo Molnar:
"Make clock_adjtime() syscall timex validation slightly more permissive
for auxiliary clocks, to not reject syscalls based on the status field
that do not try to modify the status field.
This makes the ABI behavior in clock_adjtime() consistent with
CLOCK_REALTIME"
* tag 'timers-urgent-2026-03-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timekeeping: Fix timex status validation for auxiliary clocks
PI and setscheduler() syscalls, resulting in kernel warnings
and misbehavior. Found during stress-testing.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-urgent-2026-03-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Ingo Molnar:
"Fix a DL scheduler bug that may corrupt internal metrics during PI and
setscheduler() syscalls, resulting in kernel warnings and misbehavior.
Found during stress-testing"
* tag 'sched-urgent-2026-03-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/deadline: Fix missing ENQUEUE_REPLENISH during PI de-boosting
- Fix possible NULL pointer dereference in trace_data_alloc()
On the error path in trace_data_alloc(), it can call trigger_data_free()
with a NULL pointer. This use to be a kfree() but was changed to
trigger_data_free() to clean up any partial initialization. The issue is
that trigger_data_free() does not expect a NULL pointer. Have
trigger_data_free() return safely on NULL pointer.
- Fix multiple events on the command line and bootconfig
If multiple events are enabled on the command line separately and not
grouped, only the last event gets enabled. That is:
trace_event=sched_switch trace_event=sched_waking
Will only enable sched_waking where as:
trace_event=sched_switch,sched_waking
Will enable both.
The bootconfig makes it even worse as the second way is the more common
method.
The issue is that a temporary buffer is used to store the events to enable
later in boot. Each time the cmdline callback is called, it overwrites
what was previously there.
Have the callback append the next value (delimited by a comma) if the
temporary buffer already has content.
- Fix command line trace_buffer_size if >= 2G
The logic to allocate the trace buffer uses "int" for the size parameter
in the command line code causing overflow issues if more that 2G is
specified.
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Merge tag 'trace-v7.0-rc2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Fix possible NULL pointer dereference in trace_data_alloc()
On the trace_data_alloc() error path, it can call trigger_data_free()
with a NULL pointer. This used to be a kfree() but was changed to
trigger_data_free() to clean up any partial initialization. The issue
is that trigger_data_free() does not expect a NULL pointer. Have
trigger_data_free() return safely on NULL pointer.
- Fix multiple events on the command line and bootconfig
If multiple events are enabled on the command line separately and not
grouped, only the last event gets enabled. That is:
trace_event=sched_switch trace_event=sched_waking
will only enable sched_waking whereas:
trace_event=sched_switch,sched_waking
will enable both.
The bootconfig makes it even worse as the second way is the more
common method.
The issue is that a temporary buffer is used to store the events to
enable later in boot. Each time the cmdline callback is called, it
overwrites what was previously there.
Have the callback append the next value (delimited by a comma) if the
temporary buffer already has content.
- Fix command line trace_buffer_size if >= 2G
The logic to allocate the trace buffer uses "int" for the size
parameter in the command line code causing overflow issues if more
that 2G is specified.
* tag 'trace-v7.0-rc2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Fix trace_buf_size= cmdline parameter with sizes >= 2G
tracing: Fix enabling multiple events on the kernel command line and bootconfig
tracing: Add NULL pointer check to trigger_data_free()
enqueue_task_scx() takes int enq_flags from the sched_class interface.
SCX enqueue flags starting at bit 32 (SCX_ENQ_PREEMPT and above) are
silently truncated when passed through activate_task(). extra_enq_flags
was added as a workaround - storing high bits in rq->scx.extra_enq_flags
and OR-ing them back in enqueue_task_scx(). However, the OR target is
still the int parameter, so the high bits are lost anyway.
The current impact is limited as the only affected flag is SCX_ENQ_PREEMPT
which is informational to the BPF scheduler - its loss means the scheduler
doesn't know about preemption but doesn't cause incorrect behavior.
Fix by renaming the int parameter to core_enq_flags and introducing a
u64 enq_flags local that merges both sources. All downstream functions
already take u64 enq_flags.
Fixes: f0e1a0643a ("sched_ext: Implement BPF extensible scheduler class")
Cc: stable@vger.kernel.org # v6.12+
Acked-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Fix an inconsistency between func_states_equal() and
collect_linked_regs():
- regsafe() uses check_ids() to verify that cached and current states
have identical register id mapping.
- func_states_equal() calls regsafe() only for registers computed as
live by compute_live_registers().
- clean_live_states() is supposed to remove dead registers from cached
states, but it can skip states belonging to an iterator-based loop.
- collect_linked_regs() collects all registers sharing the same id,
ignoring the marks computed by compute_live_registers().
Linked registers are stored in the state's jump history.
- backtrack_insn() marks all linked registers for an instruction
as precise whenever one of the linked registers is precise.
The above might lead to a scenario:
- There is an instruction I with register rY known to be dead at I.
- Instruction I is reached via two paths: first A, then B.
- On path A:
- There is an id link between registers rX and rY.
- Checkpoint C is created at I.
- Linked register set {rX, rY} is saved to the jump history.
- rX is marked as precise at I, causing both rX and rY
to be marked precise at C.
- On path B:
- There is no id link between registers rX and rY,
otherwise register states are sub-states of those in C.
- Because rY is dead at I, check_ids() returns true.
- Current state is considered equal to checkpoint C,
propagate_precision() propagates spurious precision
mark for register rY along the path B.
- Depending on a program, this might hit verifier_bug()
in the backtrack_insn(), e.g. if rY ∈ [r1..r5]
and backtrack_insn() spots a function call.
The reproducer program is in the next patch.
This was hit by sched_ext scx_lavd scheduler code.
Changes in tests:
- verifier_scalar_ids.c selftests need modification to preserve
some registers as live for __msg() checks.
- exceptions_assert.c adjusted to match changes in the verifier log,
R0 is dead after conditional instruction and thus does not get
range.
- precise.c adjusted to match changes in the verifier log, register r9
is dead after comparison and it's range is not important for test.
Reported-by: Emil Tsalapatis <emil@etsalapatis.com>
Fixes: 0fb3cf6110 ("bpf: use register liveness information for func_states_equal")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260306-linked-regs-and-propagate-precision-v1-1-18e859be570d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Some of the sizing logic through tracer_alloc_buffers() uses int
internally, causing unexpected behavior if the user passes a value that
does not fit in an int (on my x86 machine, the result is uselessly tiny
buffers).
Fix by plumbing the parameter's real type (unsigned long) through to the
ring buffer allocation functions, which already use unsigned long.
It has always been possible to create larger ring buffers via the sysfs
interface: this only affects the cmdline parameter.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/bff42a4288aada08bdf74da3f5b67a2c28b761f8.1772852067.git.calvin@wbinvd.org
Fixes: 73c5162aa3 ("tracing: keep ring buffer to minimum size till used")
Signed-off-by: Calvin Owens <calvin@wbinvd.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Same as in __reg64_deduce_bounds(), refine s32/u32 ranges
in __reg32_deduce_bounds() in the following situations:
- s32 range crosses U32_MAX/0 boundary, positive part of the s32 range
overlaps with u32 range:
0 U32_MAX
| [xxxxxxxxxxxxxx u32 range xxxxxxxxxxxxxx] |
|----------------------------|----------------------------|
|xxxxx s32 range xxxxxxxxx] [xxxxxxx|
0 S32_MAX S32_MIN -1
- s32 range crosses U32_MAX/0 boundary, negative part of the s32 range
overlaps with u32 range:
0 U32_MAX
| [xxxxxxxxxxxxxx u32 range xxxxxxxxxxxxxx] |
|----------------------------|----------------------------|
|xxxxxxxxx] [xxxxxxxxxxxx s32 range |
0 S32_MAX S32_MIN -1
- No refinement if ranges overlap in two intervals.
This helps for e.g. consider the following program:
call %[bpf_get_prandom_u32];
w0 &= 0xffffffff;
if w0 < 0x3 goto 1f; // on fall-through u32 range [3..U32_MAX]
if w0 s> 0x1 goto 1f; // on fall-through s32 range [S32_MIN..1]
if w0 s< 0x0 goto 1f; // range can be narrowed to [S32_MIN..-1]
r10 = 0;
1: ...;
The reg_bounds.c selftest is updated to incorporate identical logic,
refinement based on non-overflowing range halves:
((x ∩ [0, smax]) ∩ (y ∩ [0, smax])) ∪
((x ∩ [smin,-1]) ∩ (y ∩ [smin,-1]))
Reported-by: Andrea Righi <arighi@nvidia.com>
Reported-by: Emil Tsalapatis <emil@etsalapatis.com>
Closes: https://lore.kernel.org/bpf/aakqucg4vcujVwif@gpd4/T/
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260306-bpf-32-bit-range-overflow-v3-1-f7f67e060a6b@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Once a task exits it has its state set to TASK_DEAD and then it is
removed from the cgroup it belonged to. The last step happens on the task
gets out of its last schedule() invocation and is delayed on PREEMPT_RT
due to locking constraints.
As a result it is possible to receive a pid via waitpid() of a task
which is still listed in cgroup.procs for the cgroup it belonged
to. This is something that systemd does not expect and as a result it
waits for its exit until a time out occurs.
This can also be reproduced on !PREEMPT_RT kernel with a significant
delay in do_exit() after exit_notify().
Hide the task from the output which have PF_EXITING set which is done
before the parent is notified. Keeping zombies with live threads
shouldn't break anything (suggested by Tejun).
Reported-by: Bert Karwatzki <spasswolf@web.de>
Closes: https://lore.kernel.org/all/20260219164648.3014-1-spasswolf@web.de/
Tested-by: Bert Karwatzki <spasswolf@web.de>
Fixes: 9311e6c29b ("cgroup: Fix sleeping from invalid context warning on PREEMPT_RT")
Cc: stable@vger.kernel.org # v6.19+
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Multiple events can be enabled on the kernel command line via a comma
separator. But if the are specified one at a time, then only the last
event is enabled. This is because the event names are saved in a temporary
buffer, and each call by the init cmdline code will reset that buffer.
This also affects names in the boot config file, as it may call the
callback multiple times with an example of:
kernel.trace_event = ":mod:rproc_qcom_common", ":mod:qrtr", ":mod:qcom_aoss"
Change the cmdline callback function to append a comma and the next value
if the temporary buffer already has content.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20260302-trace-events-allow-multiple-modules-v1-1-ce4436e37fb8@oss.qualcomm.com
Signed-off-by: Andrei-Alexandru Tachici <andrei-alexandru.tachici@oss.qualcomm.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
If trigger_data_alloc() fails and returns NULL, event_hist_trigger_parse()
jumps to the out_free error path. While kfree() safely handles a NULL
pointer, trigger_data_free() does not. This causes a NULL pointer
dereference in trigger_data_free() when evaluating
data->cmd_ops->set_filter.
Fix the problem by adding a NULL pointer check to trigger_data_free().
The problem was found by an experimental code review agent based on
gemini-3.1-pro while reviewing backports into v6.18.y.
Cc: Miaoqian Lin <linmq006@gmail.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://patch.msgid.link/20260305193339.2810953-1-linux@roeck-us.net
Fixes: 0550069cc2 ("tracing: Properly process error handling in event_hist_trigger_parse()")
Assisted-by: Gemini:gemini-3.1-pro
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Besides deferring the call to housekeeping_update(), commit 6df415aa46
("cgroup/cpuset: Defer housekeeping_update() calls from CPU hotplug
to workqueue") also defers the rebuild_sched_domains() call to
the workqueue. So a new offline CPU may still be in a sched domain
or new online CPU not showing up in the sched domains for a short
transition period. That could be a problem in some corner cases and
can be the cause of a reported test failure[1]. Fix it by calling
rebuild_sched_domains_cpuslocked() directly in hotplug as before. If
isolated partition invalidation or recreation is being done, the
housekeeping_update() call to update the housekeeping cpumasks will
still be deferred to a workqueue.
In commit 3bfe479671 ("cgroup/cpuset: Move
housekeeping_update()/rebuild_sched_domains() together"),
housekeeping_update() is called before rebuild_sched_domains() because
it needs to access the HK_TYPE_DOMAIN housekeeping cpumask. That is now
changed to use the static HK_TYPE_DOMAIN_BOOT cpumask as HK_TYPE_DOMAIN
cpumask is now changeable at run time. As a result, we can move the
rebuild_sched_domains() call before housekeeping_update() with
the slight advantage that it will be done in the same cpus_read_lock
critical section without the possibility of interference by a concurrent
cpu hot add/remove operation.
As it doesn't make sense to acquire cpuset_mutex/cpuset_top_mutex after
calling housekeeping_update() and immediately release them again, move
the cpuset_full_unlock() operation inside update_hk_sched_domains()
and rename it to cpuset_update_sd_hk_unlock() to signify that it will
release the full set of locks.
[1] https://lore.kernel.org/lkml/1a89aceb-48db-4edd-a730-b445e41221fe@nvidia.com
Fixes: 6df415aa46 ("cgroup/cpuset: Defer housekeeping_update() calls from CPU hotplug to workqueue")
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Reviewed-by: Chen Ridong <chenridong@huaweicloud.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Commit 0927780c90 ("sched_ext: Use READ_ONCE() for lock-free reads
of module param variables") annotated the plain reads of
scx_slice_bypass_us and scx_bypass_lb_intv_us in bypass_lb_cpu(), but
missed a third site in scx_bypass():
WRITE_ONCE(scx_slice_dfl, scx_slice_bypass_us * NSEC_PER_USEC);
scx_slice_bypass_us is a module parameter writable via sysfs in
process context through set_slice_us() -> param_set_uint_minmax(),
which performs a plain store without holding bypass_lock. scx_bypass()
reads the variable under bypass_lock, but since the writer does not
take that lock, the two accesses are concurrent.
WRITE_ONCE() only applies volatile semantics to the store of
scx_slice_dfl -- the val expression containing scx_slice_bypass_us is
evaluated as a plain read, providing no protection against concurrent
writes.
Wrap the read with READ_ONCE() to complete the annotation started by
commit 0927780c90 and make the access KCSAN-clean, consistent with
the existing READ_ONCE(scx_slice_bypass_us) in bypass_lb_cpu().
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
show_cpu_pool_hog() and show_cpu_pools_hogs() no longer only dump CPU
hogs — since commit 8823eaef45 ("workqueue: Show all busy workers in
stall diagnostics"), they dump every in-flight worker in the pool's
busy_hash.
Rename them to show_cpu_pool_busy_workers() and
show_cpu_pools_busy_workers() to accurately describe what they do.
Also fix the pr_info() message to say "stalled worker pools" instead of
"stalled CPU-bound worker pools", since sleeping/blocked workers are now
included.
No functional change.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Merge tag 'block-7.0-20260305' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux
Pull block fixes from Jens Axboe:
- NVMe pull request via Keith:
- Improve quirk visibility and configurability (Maurizio)
- Fix runtime user modification to queue setup (Keith)
- Fix multipath leak on try_module_get failure (Keith)
- Ignore ambiguous spec definitions for better atomics support
(John)
- Fix admin queue leak on controller reset (Ming)
- Fix large allocation in persistent reservation read keys
(Sungwoo Kim)
- Fix fcloop callback handling (Justin)
- Securely free DHCHAP secrets (Daniel)
- Various cleanups and typo fixes (John, Wilfred)
- Avoid a circular lock dependency issue in the sysfs nr_requests or
scheduler store handling
- Fix a circular lock dependency with the pcpu mutex and the queue
freeze lock
- Cleanup for bio_copy_kern(), using __bio_add_page() rather than the
bio_add_page(), as adding a page here cannot fail. The exiting code
had broken cleanup for the error condition, so make it clear that the
error condition cannot happen
- Fix for a __this_cpu_read() in preemptible context splat
* tag 'block-7.0-20260305' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux:
block: use trylock to avoid lockdep circular dependency in sysfs
nvme: fix memory allocation in nvme_pr_read_keys()
block: use __bio_add_page in bio_copy_kern
block: break pcpu_alloc_mutex dependency on freeze_lock
blktrace: fix __this_cpu_read/write in preemptible context
nvme-multipath: fix leak on try_module_get failure
nvmet-fcloop: Check remoteport port_state before calling done callback
nvme-pci: do not try to add queue maps at runtime
nvme-pci: cap queue creation to used queues
nvme-pci: ensure we're polling a polled queue
nvme: fix memory leak in quirks_param_set()
nvme: correct comment about nvme_ns_remove()
nvme: stop setting namespace gendisk device driver data
nvme: add support for dynamic quirk configuration via module parameter
nvme: fix admin queue leak on controller reset
nvme-fabrics: use kfree_sensitive() for DHCHAP secrets
nvme: stop using AWUPF
nvme: expose active quirks in sysfs
nvme/host: fixup some typos
kthread_exit became a macro to do_exit in commit 28aaa9c399
("kthread: consolidate kthread exit paths to prevent use-after-free"),
so there is no kthread_exit function BTF ID to resolve. Remove it from
noreturn_deny to avoid resolve_btfids unresolved symbol warnings.
Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
show_cpu_pool_hog() only prints workers whose task is currently running
on the CPU (task_is_running()). This misses workers that are busy
processing a work item but are sleeping or blocked — for example, a
worker that clears PF_WQ_WORKER and enters wait_event_idle(). Such a
worker still occupies a pool slot and prevents progress, yet produces
an empty backtrace section in the watchdog output.
This is happening on real arm64 systems, where
toggle_allocation_gate() IPIs every single CPU in the machine (which
lacks NMI), causing workqueue stalls that show empty backtraces because
toggle_allocation_gate() is sleeping in wait_event_idle().
Remove the task_is_running() filter so every in-flight worker in the
pool's busy_hash is dumped. The busy_hash is protected by pool->lock,
which is already held.
Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
When diagnosing workqueue stalls, knowing how long each in-flight work
item has been executing is valuable. Add a current_start timestamp
(jiffies) to struct worker, set it when a work item begins execution in
process_one_work(), and print the elapsed wall-clock time in show_pwq().
Unlike current_at (which tracks CPU runtime and resets on wakeup for
CPU-intensive detection), current_start is never reset because the
diagnostic cares about total wall-clock time including sleeps.
Before: in-flight: 165:stall_work_fn [wq_stall]
After: in-flight: 165:stall_work_fn [wq_stall] for 100s
Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
The watchdog_ts name doesn't convey what the timestamp actually tracks.
This field tracks the last time a workqueue got progress.
Rename it to last_progress_ts to make it clear that it records when the
pool last made forward progress (started processing new work items).
No functional change.
Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
pr_cont_worker_id() checks pool->flags against WQ_BH, which is a
workqueue-level flag (defined in workqueue.h). Pool flags use a
separate namespace with POOL_* constants (defined in workqueue.c).
The correct constant is POOL_BH. Both WQ_BH and POOL_BH are defined
as (1 << 0) so this has no behavioral impact, but it is semantically
wrong and inconsistent with every other pool-level BH check in the
file.
Fixes: 4cb1ef6460 ("workqueue: Implement BH workqueues to eventually replace tasklets")
Signed-off-by: Breno Leitao <leitao@debian.org>
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
The task ownership state machine in sched_ext is quite hard to follow
from the code alone. The interaction of ownership states, memory
ordering rules and cross-CPU "lock dancing" makes the overall model
subtle.
Extend the documentation next to scx_ops_state to provide a more
structured and self-contained description of the state transitions and
their synchronization rules.
The new reference should make the code easier to reason about and
maintain and can help future contributors understand the overall
task-ownership workflow.
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
bypass_lb_cpu() reads scx_bypass_lb_intv_us and scx_slice_bypass_us
without holding any lock, in timer callback context where module
parameter writes via sysfs can happen concurrently:
min_delta_us = scx_bypass_lb_intv_us / SCX_BYPASS_LB_MIN_DELTA_DIV;
^^^^^^^^^^^^^^^^^^^^
plain read -- KCSAN data race
if (delta < DIV_ROUND_UP(min_delta_us, scx_slice_bypass_us))
^^^^^^^^^^^^^^^^^
plain read -- KCSAN data race
scx_bypass_lb_intv_us already uses READ_ONCE() in scx_bypass_lb_timerfn()
and scx_bypass() for its other lock-free read sites, leaving
bypass_lb_cpu() inconsistent. scx_slice_bypass_us has the same
lock-free access pattern in the same function.
Fix both plain reads by using READ_ONCE() to complete the concurrent
access annotation and make the code KCSAN-clean.
Signed-off-by: zhidao su <suzhidao@xiaomi.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
- Fix thresh_return of function graph tracer
The update to store data on the shadow stack removed the abuse of
using the task recursion word as a way to keep track of what functions
to ignore. The trace_graph_return() was updated to handle this, but
when function_graph tracer is using a threshold (only trace functions
that took longer than a specified time), it uses
trace_graph_thresh_return() instead. This function was still incorrectly
using the task struct recursion word causing the function graph tracer to
permanently set all functions to "notrace"
- Fix thresh_return nosleep accounting
When the calltime was moved to the shadow stack storage instead of being
on the fgraph descriptor, the calculations for the amount of sleep time
was updated. The calculation was done in the trace_graph_thresh_return()
function, which also called the trace_graph_return(), which did the
calculation again, causing the time to be doubled.
Remove the call to trace_graph_return() as what it needed to do wasn't
that much, and just do the work in trace_graph_thresh_return().
- Fix syscall trace event activation on boot up
The syscall trace events are pseudo events attached to the raw_syscall
tracepoints. When the first syscall event is enabled, it enables the
raw_syscall tracepoint and doesn't need to do anything when a second
syscall event is also enabled.
When events are enabled via the kernel command line, syscall events
are partially enabled as the enabling is called before rcu_init.
This is due to allow early events to be enabled immediately. Because
kernel command line events do not distinguish between different
types of events, the syscall events are enabled here but are not fully
functioning. After rcu_init, they are disabled and re-enabled so that
they can be fully enabled. The problem happened is that this
"disable-enable" is done one at a time. If more than one syscall event
is specified on the command line, by disabling them one at a time,
the counter never gets to zero, and the raw_syscall is not disabled and
enabled, keeping the syscall events in their non-fully functional state.
Instead, disable all events and re-enabled them all, as that will ensure
the raw_syscall event is also disabled and re-enabled.
- Disable preemption in ftrace pid filtering
The ftrace pid filtering attaches to the fork and exit tracepoints to
add or remove pids that should be traced. They access variables protected
by RCU (preemption disabled). Now that tracepoint callbacks are called with
preemption enabled, this protection needs to be added explicitly, and
not depend on the functions being called with preemption disabled.
- Disable preemption in event pid filtering
The event pid filtering needs the same preemption disabling guards as
ftrace pid filtering.
- Fix accounting of the memory mapped ring buffer on fork
Memory mapping the ftrace ring buffer sets the vm_flags to DONTCOPY. But
this does not prevent the application from calling madvise(MADVISE_DOFORK).
This causes the mapping to be copied on fork. After the first tasks exits,
the mapping is considered unmapped by everyone. But when he second task
exits, the counter goes below zero and triggers a WARN_ON.
Since nothing prevents two separate tasks from mmapping the ftrace ring
buffer (although two mappings may mess each other up), there's no reason
to stop the memory from being copied on fork.
Update the vm_operations to have an ".open" handler to update the
accounting and let the ring buffer know someone else has it mapped.
- Add all ftrace headers in MAINTAINERS file
The MAINTAINERS file only specifies include/linux/ftrace.h But misses
ftrace_irq.h and ftrace_regs.h. Make the file use wildcards to get all
*ftrace* files.
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Merge tag 'trace-v7.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Fix thresh_return of function graph tracer
The update to store data on the shadow stack removed the abuse of
using the task recursion word as a way to keep track of what
functions to ignore. The trace_graph_return() was updated to handle
this, but when function_graph tracer is using a threshold (only trace
functions that took longer than a specified time), it uses
trace_graph_thresh_return() instead.
This function was still incorrectly using the task struct recursion
word causing the function graph tracer to permanently set all
functions to "notrace"
- Fix thresh_return nosleep accounting
When the calltime was moved to the shadow stack storage instead of
being on the fgraph descriptor, the calculations for the amount of
sleep time was updated. The calculation was done in the
trace_graph_thresh_return() function, which also called the
trace_graph_return(), which did the calculation again, causing the
time to be doubled.
Remove the call to trace_graph_return() as what it needed to do
wasn't that much, and just do the work in
trace_graph_thresh_return().
- Fix syscall trace event activation on boot up
The syscall trace events are pseudo events attached to the
raw_syscall tracepoints. When the first syscall event is enabled, it
enables the raw_syscall tracepoint and doesn't need to do anything
when a second syscall event is also enabled.
When events are enabled via the kernel command line, syscall events
are partially enabled as the enabling is called before rcu_init. This
is due to allow early events to be enabled immediately. Because
kernel command line events do not distinguish between different types
of events, the syscall events are enabled here but are not fully
functioning. After rcu_init, they are disabled and re-enabled so that
they can be fully enabled.
The problem happened is that this "disable-enable" is done one at a
time. If more than one syscall event is specified on the command
line, by disabling them one at a time, the counter never gets to
zero, and the raw_syscall is not disabled and enabled, keeping the
syscall events in their non-fully functional state.
Instead, disable all events and re-enabled them all, as that will
ensure the raw_syscall event is also disabled and re-enabled.
- Disable preemption in ftrace pid filtering
The ftrace pid filtering attaches to the fork and exit tracepoints to
add or remove pids that should be traced. They access variables
protected by RCU (preemption disabled). Now that tracepoint callbacks
are called with preemption enabled, this protection needs to be added
explicitly, and not depend on the functions being called with
preemption disabled.
- Disable preemption in event pid filtering
The event pid filtering needs the same preemption disabling guards as
ftrace pid filtering.
- Fix accounting of the memory mapped ring buffer on fork
Memory mapping the ftrace ring buffer sets the vm_flags to DONTCOPY.
But this does not prevent the application from calling
madvise(MADVISE_DOFORK). This causes the mapping to be copied on
fork. After the first tasks exits, the mapping is considered unmapped
by everyone. But when he second task exits, the counter goes below
zero and triggers a WARN_ON.
Since nothing prevents two separate tasks from mmapping the ftrace
ring buffer (although two mappings may mess each other up), there's
no reason to stop the memory from being copied on fork.
Update the vm_operations to have an ".open" handler to update the
accounting and let the ring buffer know someone else has it mapped.
- Add all ftrace headers in MAINTAINERS file
The MAINTAINERS file only specifies include/linux/ftrace.h But misses
ftrace_irq.h and ftrace_regs.h. Make the file use wildcards to get
all *ftrace* files.
* tag 'trace-v7.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ftrace: Add MAINTAINERS entries for all ftrace headers
tracing: Fix WARN_ON in tracing_buffers_mmap_close
tracing: Disable preemption in the tracepoint callbacks handling filtered pids
ftrace: Disable preemption in the tracepoint callbacks handling filtered pids
tracing: Fix syscall events activation by ensuring refcount hits zero
fgraph: Fix thresh_return nosleeptime double-adjust
fgraph: Fix thresh_return clear per-task notrace
- Fix a potential kernel panic in the module loader by adding a bounds
check for the ELF section index. This prevents crashes if attempting
to load a module that uses SHN_XINDEX or is corrupted.
- Fix the Kconfig menu layout for module versioning, signing, and
compression options so they correctly appear as submenus in menuconfig.
- Remove a redundant lockdep_free_key_range() call in the load_module()
error path. This is already handled by module_deallocate() calling
free_mod_mem() since the module_memory rework.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
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Merge tag 'modules-7.0-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux
Pull module fixes from Sami Tolvanen:
- Fix a potential kernel panic in the module loader by adding a bounds
check for the ELF section index. This prevents crashes if attempting
to load a module that uses SHN_XINDEX or is corrupted.
- Fix the Kconfig menu layout for module versioning, signing, and
compression options so they correctly appear as submenus in
menuconfig.
- Remove a redundant lockdep_free_key_range() call in the load_module()
error path. This is already handled by module_deallocate() calling
free_mod_mem() since the module_memory rework.
* tag 'modules-7.0-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux:
module: Fix kernel panic when a symbol st_shndx is out of bounds
module: Fix the modversions and signing submenus
module: Remove duplicate freeing of lockdep classes
The timekeeping_validate_timex() function validates the timex status
of an auxiliary system clock even when the status is not to be changed,
which causes unexpected errors for applications that make read-only
clock_adjtime() calls, or set some other timex fields, but without
clearing the status field.
Do the AUX-specific status validation only when the modes field contains
ADJ_STATUS, i.e. the application is actually trying to change the
status. This makes the AUX-specific clock_adjtime() behavior consistent
with CLOCK_REALTIME.
Fixes: 4eca49d0b6 ("timekeeping: Prepare do_adtimex() for auxiliary clocks")
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260225085231.276751-1-mlichvar@redhat.com
bpf_iter_scx_dsq_new() reads dsq->seq via READ_ONCE() without holding
any lock, making dsq->seq a lock-free concurrently accessed variable.
However, dispatch_enqueue(), the sole writer of dsq->seq, uses a plain
increment without the matching WRITE_ONCE() on the write side:
dsq->seq++;
^^^^^^^^^^^
plain write -- KCSAN data race
The KCSAN documentation requires that if one accessor uses READ_ONCE()
or WRITE_ONCE() on a variable to annotate lock-free access, all other
accesses must also use the appropriate accessor. A plain write leaves
the pair incomplete and will trigger KCSAN warnings.
Fix by using WRITE_ONCE() for the write side of the update:
WRITE_ONCE(dsq->seq, dsq->seq + 1);
This is consistent with bpf_iter_scx_dsq_new() and makes the
concurrent access annotation complete and KCSAN-clean.
Signed-off-by: zhidao su <suzhidao@xiaomi.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
* Fix error when reporting jiffies converted values back to user space
Return the converted value instead of "Invalid argument" error.
* Testing
Spent around a week in linux-next -enough for this small fix-
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Merge tag 'sysctl-7.00-fixes-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl
Pull sysctl fix from Joel Granados:
- Fix error when reporting jiffies converted values back to user space
Return the converted value instead of "Invalid argument" error
* tag 'sysctl-7.00-fixes-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl:
time/jiffies: Fix sysctl file error on configurations where USER_HZ < HZ
Running stress-ng --schedpolicy 0 on an RT kernel on a big machine
might lead to the following WARNINGs (edited).
sched: DL de-boosted task PID 22725: REPLENISH flag missing
WARNING: CPU: 93 PID: 0 at kernel/sched/deadline.c:239 dequeue_task_dl+0x15c/0x1f8
... (running_bw underflow)
Call trace:
dequeue_task_dl+0x15c/0x1f8 (P)
dequeue_task+0x80/0x168
deactivate_task+0x24/0x50
push_dl_task+0x264/0x2e0
dl_task_timer+0x1b0/0x228
__hrtimer_run_queues+0x188/0x378
hrtimer_interrupt+0xfc/0x260
...
The problem is that when a SCHED_DEADLINE task (lock holder) is
changed to a lower priority class via sched_setscheduler(), it may
fail to properly inherit the parameters of potential DEADLINE donors
if it didn't already inherit them in the past (shorter deadline than
donor's at that time). This might lead to bandwidth accounting
corruption, as enqueue_task_dl() won't recognize the lock holder as
boosted.
The scenario occurs when:
1. A DEADLINE task (donor) blocks on a PI mutex held by another
DEADLINE task (holder), but the holder doesn't inherit parameters
(e.g., it already has a shorter deadline)
2. sched_setscheduler() changes the holder from DEADLINE to a lower
class while still holding the mutex
3. The holder should now inherit DEADLINE parameters from the donor
and be enqueued with ENQUEUE_REPLENISH, but this doesn't happen
Fix the issue by introducing __setscheduler_dl_pi(), which detects when
a DEADLINE (proper or boosted) task gets setscheduled to a lower
priority class. In case, the function makes the task inherit DEADLINE
parameters of the donoer (pi_se) and sets ENQUEUE_REPLENISH flag to
ensure proper bandwidth accounting during the next enqueue operation.
Fixes: 2279f540ea ("sched/deadline: Fix priority inheritance with multiple scheduling classes")
Reported-by: Bruno Goncalves <bgoncalv@redhat.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260302-upstream-fix-deadline-piboost-b4-v3-1-6ba32184a9e0@redhat.com
Commit 2dc164a48e ("sysctl: Create converter functions with two new
macros") incorrectly returns error to user space when jiffies sysctl
converter is used. The old overflow check got replaced with an
unconditional one:
+ if (USER_HZ < HZ)
+ return -EINVAL;
which will always be true on configurations with "USER_HZ < HZ".
Remove the check; it is no longer needed as clock_t_to_jiffies() returns
ULONG_MAX for the overflow case and proc_int_u2k_conv_uop() checks for
"> INT_MAX" after conversion
Fixes: 2dc164a48e ("sysctl: Create converter functions with two new macros")
Reported-by: Colm Harrington <colm.harrington@oracle.com>
Signed-off-by: Gerd Rausch <gerd.rausch@oracle.com>
Signed-off-by: Joel Granados <joel.granados@kernel.org>
When a process forks, the child process copies the parent's VMAs but the
user_mapped reference count is not incremented. As a result, when both the
parent and child processes exit, tracing_buffers_mmap_close() is called
twice. On the second call, user_mapped is already 0, causing the function to
return -ENODEV and triggering a WARN_ON.
Normally, this isn't an issue as the memory is mapped with VM_DONTCOPY set.
But this is only a hint, and the application can call
madvise(MADVISE_DOFORK) which resets the VM_DONTCOPY flag. When the
application does that, it can trigger this issue on fork.
Fix it by incrementing the user_mapped reference count without re-mapping
the pages in the VMA's open callback.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Vincent Donnefort <vdonnefort@google.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Link: https://patch.msgid.link/20260227025842.1085206-1-wangqing7171@gmail.com
Fixes: cf9f0f7c4c ("tracing: Allow user-space mapping of the ring-buffer")
Reported-by: syzbot+3b5dd2030fe08afdf65d@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=3b5dd2030fe08afdf65d
Tested-by: syzbot+3b5dd2030fe08afdf65d@syzkaller.appspotmail.com
Signed-off-by: Qing Wang <wangqing7171@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When function trace PID filtering is enabled, the function tracer will
attach a callback to the fork tracepoint as well as the exit tracepoint
that will add the forked child PID to the PID filtering list as well as
remove the PID that is exiting.
Commit a46023d561 ("tracing: Guard __DECLARE_TRACE() use of
__DO_TRACE_CALL() with SRCU-fast") removed the disabling of preemption
when calling tracepoint callbacks.
The callbacks used for the PID filtering accounting depended on preemption
being disabled, and now the trigger a "suspicious RCU usage" warning message.
Make them explicitly disable preemption.
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20260302213546.156e3e4f@gandalf.local.home
Fixes: a46023d561 ("tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
When multiple syscall events are specified in the kernel command line
(e.g., trace_event=syscalls:sys_enter_openat,syscalls:sys_enter_close),
they are often not captured after boot, even though they appear enabled
in the tracing/set_event file.
The issue stems from how syscall events are initialized. Syscall
tracepoints require the global reference count (sys_tracepoint_refcount)
to transition from 0 to 1 to trigger the registration of the syscall
work (TIF_SYSCALL_TRACEPOINT) for tasks, including the init process (pid 1).
The current implementation of early_enable_events() with disable_first=true
used an interleaved sequence of "Disable A -> Enable A -> Disable B -> Enable B".
If multiple syscalls are enabled, the refcount never drops to zero,
preventing the 0->1 transition that triggers actual registration.
Fix this by splitting early_enable_events() into two distinct phases:
1. Disable all events specified in the buffer.
2. Enable all events specified in the buffer.
This ensures the refcount hits zero before re-enabling, allowing syscall
events to be properly activated during early boot.
The code is also refactored to use a helper function to avoid logic
duplication between the disable and enable phases.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20260224023544.1250787-1-hehuiwen@kylinos.cn
Fixes: ce1039bd3a ("tracing: Fix enabling of syscall events on the command line")
Signed-off-by: Huiwen He <hehuiwen@kylinos.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
trace_graph_thresh_return() called handle_nosleeptime() and then delegated
to trace_graph_return(), which calls handle_nosleeptime() again. When
sleep-time accounting is disabled this double-adjusts calltime and can
produce bogus durations (including underflow).
Fix this by computing rettime once, applying handle_nosleeptime() only
once, using the adjusted calltime for threshold comparison, and writing
the return event directly via __trace_graph_return() when the threshold is
met.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260221113314048jE4VRwIyZEALiYByGK0My@zte.com.cn
Fixes: 3c9880f3ab ("ftrace: Use a running sleeptime instead of saving on shadow stack")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Shengming Hu <hu.shengming@zte.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When tracing_thresh is enabled, function graph tracing uses
trace_graph_thresh_return() as the return handler. Unlike
trace_graph_return(), it did not clear the per-task TRACE_GRAPH_NOTRACE
flag set by the entry handler for set_graph_notrace addresses. This could
leave the task permanently in "notrace" state and effectively disable
function graph tracing for that task.
Mirror trace_graph_return()'s per-task notrace handling by clearing
TRACE_GRAPH_NOTRACE and returning early when set.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260221113007819YgrZsMGABff4Rc-O_fZxL@zte.com.cn
Fixes: b84214890a ("function_graph: Move graph notrace bit to shadow stack global var")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Shengming Hu <hu.shengming@zte.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The root cause of this bug is that when 'bpf_link_put' reduces the
refcount of 'shim_link->link.link' to zero, the resource is considered
released but may still be referenced via 'tr->progs_hlist' in
'cgroup_shim_find'. The actual cleanup of 'tr->progs_hlist' in
'bpf_shim_tramp_link_release' is deferred. During this window, another
process can cause a use-after-free via 'bpf_trampoline_link_cgroup_shim'.
Based on Martin KaFai Lau's suggestions, I have created a simple patch.
To fix this:
Add an atomic non-zero check in 'bpf_trampoline_link_cgroup_shim'.
Only increment the refcount if it is not already zero.
Testing:
I verified the fix by adding a delay in
'bpf_shim_tramp_link_release' to make the bug easier to trigger:
static void bpf_shim_tramp_link_release(struct bpf_link *link)
{
/* ... */
if (!shim_link->trampoline)
return;
+ msleep(100);
WARN_ON_ONCE(bpf_trampoline_unlink_prog(&shim_link->link,
shim_link->trampoline, NULL));
bpf_trampoline_put(shim_link->trampoline);
}
Before the patch, running a PoC easily reproduced the crash(almost 100%)
with a call trace similar to KaiyanM's report.
After the patch, the bug no longer occurs even after millions of
iterations.
Fixes: 69fd337a97 ("bpf: per-cgroup lsm flavor")
Reported-by: Kaiyan Mei <M202472210@hust.edu.cn>
Closes: https://lore.kernel.org/bpf/3c4ebb0b.46ff8.19abab8abe2.Coremail.kaiyanm@hust.edu.cn/
Signed-off-by: Lang Xu <xulang@uniontech.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/279EEE1BA1DDB49D+20260303095217.34436-1-xulang@uniontech.com
- Fix circular locking dependency in cpuset partition code by deferring
housekeeping_update() calls to a workqueue instead of calling them
directly under cpus_read_lock.
- Fix null-ptr-deref in rebuild_sched_domains_cpuslocked() when
generate_sched_domains() returns NULL due to kmalloc failure.
- Fix incorrect cpuset behavior for effective_xcpus in
partition_xcpus_del() and cpuset_update_tasks_cpumask() in
update_cpumasks_hier().
- Fix race between task migration and cgroup iteration.
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Merge tag 'cgroup-for-7.0-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
- Fix circular locking dependency in cpuset partition code by
deferring housekeeping_update() calls to a workqueue instead
of calling them directly under cpus_read_lock
- Fix null-ptr-deref in rebuild_sched_domains_cpuslocked() when
generate_sched_domains() returns NULL due to kmalloc failure
- Fix incorrect cpuset behavior for effective_xcpus in
partition_xcpus_del() and cpuset_update_tasks_cpumask()
in update_cpumasks_hier()
- Fix race between task migration and cgroup iteration
* tag 'cgroup-for-7.0-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup/cpuset: fix null-ptr-deref in rebuild_sched_domains_cpuslocked
cgroup/cpuset: Call housekeeping_update() without holding cpus_read_lock
cgroup/cpuset: Defer housekeeping_update() calls from CPU hotplug to workqueue
cgroup/cpuset: Move housekeeping_update()/rebuild_sched_domains() together
kselftest/cgroup: Simplify test_cpuset_prs.sh by removing "S+" command
cgroup/cpuset: Set isolated_cpus_updating only if isolated_cpus is changed
cgroup/cpuset: Clarify exclusion rules for cpuset internal variables
cgroup/cpuset: Fix incorrect use of cpuset_update_tasks_cpumask() in update_cpumasks_hier()
cgroup/cpuset: Fix incorrect change to effective_xcpus in partition_xcpus_del()
cgroup: fix race between task migration and iteration
- Fix starvation of scx_enable() under fair-class saturation by
offloading the enable path to an RT kthread.
- Fix out-of-bounds access in idle mask initialization on systems with
non-contiguous NUMA node IDs.
- Fix a preemption window during scheduler exit and a refcount underflow
in cgroup init error path.
- Fix SCX_EFLAG_INITIALIZED being a no-op flag.
- Add READ_ONCE() annotations for KCSAN-clean lockless accesses and
replace naked scx_root dereferences with container_of() in kobject
callbacks.
- Tooling and selftest fixes: compilation issues with clang 17,
strtoul() misuse, unused options cleanup, and Kconfig sync.
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Merge tag 'sched_ext-for-7.0-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext
Pull sched_ext fixes from Tejun Heo:
- Fix starvation of scx_enable() under fair-class saturation by
offloading the enable path to an RT kthread
- Fix out-of-bounds access in idle mask initialization on systems with
non-contiguous NUMA node IDs
- Fix a preemption window during scheduler exit and a refcount
underflow in cgroup init error path
- Fix SCX_EFLAG_INITIALIZED being a no-op flag
- Add READ_ONCE() annotations for KCSAN-clean lockless accesses and
replace naked scx_root dereferences with container_of() in kobject
callbacks
- Tooling and selftest fixes: compilation issues with clang 17,
strtoul() misuse, unused options cleanup, and Kconfig sync
* tag 'sched_ext-for-7.0-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
sched_ext: Fix starvation of scx_enable() under fair-class saturation
sched_ext: Remove redundant css_put() in scx_cgroup_init()
selftests/sched_ext: Fix peek_dsq.bpf.c compile error for clang 17
selftests/sched_ext: Add -fms-extensions to bpf build flags
tools/sched_ext: Add -fms-extensions to bpf build flags
sched_ext: Use READ_ONCE() for plain reads of scx_watchdog_timeout
sched_ext: Replace naked scx_root dereferences in kobject callbacks
sched_ext: Use READ_ONCE() for the read side of dsq->nr update
tools/sched_ext: fix strtoul() misuse in scx_hotplug_seq()
sched_ext: Fix SCX_EFLAG_INITIALIZED being a no-op flag
sched_ext: Fix out-of-bounds access in scx_idle_init_masks()
sched_ext: Disable preemption between scx_claim_exit() and kicking helper work
tools/sched_ext: Add Kconfig to sync with upstream
tools/sched_ext: Sync README.md Kconfig with upstream scx
selftests/sched_ext: Remove duplicated unistd.h include in rt_stall.c
tools/sched_ext: scx_sdt: Remove unused '-f' option
tools/sched_ext: scx_central: Remove unused '-p' option
selftests/sched_ext: Fix unused-result warning for read()
selftests/sched_ext: Abort test loop on signal
During scx_enable(), the READY -> ENABLED task switching loop changes the
calling thread's sched_class from fair to ext. Since fair has higher
priority than ext, saturating fair-class workloads can indefinitely starve
the enable thread, hanging the system. This was introduced when the enable
path switched from preempt_disable() to scx_bypass() which doesn't protect
against fair-class starvation. Note that the original preempt_disable()
protection wasn't complete either - in partial switch modes, the calling
thread could still be starved after preempt_enable() as it may have been
switched to ext class.
Fix it by offloading the enable body to a dedicated system-wide RT
(SCHED_FIFO) kthread which cannot be starved by either fair or ext class
tasks. scx_enable() lazily creates the kthread on first use and passes the
ops pointer through a struct scx_enable_cmd containing the kthread_work,
then synchronously waits for completion.
The workfn runs on a different kthread from sch->helper (which runs
disable_work), so it can safely flush disable_work on the error path
without deadlock.
Fixes: 8c2090c504 ("sched_ext: Initialize in bypass mode")
Cc: stable@vger.kernel.org # v6.12+
Signed-off-by: Tejun Heo <tj@kernel.org>
The iterator css_for_each_descendant_pre() walks the cgroup hierarchy
under cgroup_lock(). It does not increment the reference counts on
yielded css structs.
According to the cgroup documentation, css_put() should only be used
to release a reference obtained via css_get() or css_tryget_online().
Since the iterator does not use either of these to acquire a reference,
calling css_put() in the error path of scx_cgroup_init() causes a
refcount underflow.
Remove the unbalanced css_put() to prevent a potential Use-After-Free
(UAF) vulnerability.
Fixes: 8195136669 ("sched_ext: Add cgroup support")
Cc: stable@vger.kernel.org # v6.12+
Signed-off-by: Cheng-Yang Chou <yphbchou0911@gmail.com>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
scx_watchdog_timeout is written with WRITE_ONCE() in scx_enable():
WRITE_ONCE(scx_watchdog_timeout, timeout);
However, three read-side accesses use plain reads without the matching
READ_ONCE():
/* check_rq_for_timeouts() - L2824 */
last_runnable + scx_watchdog_timeout
/* scx_watchdog_workfn() - L2852 */
scx_watchdog_timeout / 2
/* scx_enable() - L5179 */
scx_watchdog_timeout / 2
The KCSAN documentation requires that if one accessor uses WRITE_ONCE()
to annotate lock-free access, all other accesses must also use the
appropriate accessor. Plain reads alongside WRITE_ONCE() leave the pair
incomplete and can trigger KCSAN warnings.
Note that scx_tick() already uses the correct READ_ONCE() annotation:
last_check + READ_ONCE(scx_watchdog_timeout)
Fix the three remaining plain reads to match, making all accesses to
scx_watchdog_timeout consistently annotated and KCSAN-clean.
Signed-off-by: zhidao su <suzhidao@xiaomi.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
scx_attr_ops_show() and scx_uevent() access scx_root->ops.name directly.
This is problematic for two reasons:
1. The file-level comment explicitly identifies naked scx_root
dereferences as a temporary measure that needs to be replaced
with proper per-instance access.
2. scx_attr_events_show(), the neighboring sysfs show function in
the same group, already uses the correct pattern:
struct scx_sched *sch = container_of(kobj, struct scx_sched, kobj);
Having inconsistent access patterns in the same sysfs/uevent
group is error-prone.
The kobject embedded in struct scx_sched is initialized as:
kobject_init_and_add(&sch->kobj, &scx_ktype, NULL, "root");
so container_of(kobj, struct scx_sched, kobj) correctly retrieves
the owning scx_sched instance in both callbacks.
Replace the naked scx_root dereferences with container_of()-based
access, consistent with scx_attr_events_show() and in preparation
for proper multi-instance scx_sched support.
Signed-off-by: zhidao su <suzhidao@xiaomi.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
scx_bpf_dsq_nr_queued() reads dsq->nr via READ_ONCE() without holding
any lock, making dsq->nr a lock-free concurrently accessed variable.
However, dsq_mod_nr(), the sole writer of dsq->nr, only uses
WRITE_ONCE() on the write side without the matching READ_ONCE() on the
read side:
WRITE_ONCE(dsq->nr, dsq->nr + delta);
^^^^^^^
plain read -- KCSAN data race
The KCSAN documentation requires that if one accessor uses READ_ONCE()
or WRITE_ONCE() on a variable to annotate lock-free access, all other
accesses must also use the appropriate accessor. A plain read on the
right-hand side of WRITE_ONCE() leaves the pair incomplete and will
trigger KCSAN warnings.
Fix by using READ_ONCE() for the read side of the update:
WRITE_ONCE(dsq->nr, READ_ONCE(dsq->nr) + delta);
This is consistent with scx_bpf_dsq_nr_queued() and makes the
concurrent access annotation complete and KCSAN-clean.
Signed-off-by: zhidao su <suzhidao@xiaomi.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
for the common HZ=100, 250 or 1000 cases, only inlining them
for odd HZ values like HZ=300.
The inlining overhead showed up in performance tests of the TCP code.
(Marked as an RFC pull request, as it's not a regression.)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'timers-urgent-2026-03-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fix from Ingo Molnar:
"Improve the inlining of jiffies_to_msecs() and jiffies_to_usecs(), for
the common HZ=100, 250 or 1000 cases. Only use a function call for odd
HZ values like HZ=300 that generate more code.
The function call overhead showed up in performance tests of the TCP
code"
* tag 'timers-urgent-2026-03-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time/jiffies: Inline jiffies_to_msecs() and jiffies_to_usecs()
- Fix zero_vruntime tracking when there's a single task running
- Fix slice protection logic
- Fix the ->vprot logic for reniced tasks
- Fix lag clamping in mixed slice workloads
- Fix objtool uaccess warning (and bug) in the
!CONFIG_RSEQ_SLICE_EXTENSION case caused by unexpected
un-inlining, which triggers with older compilers
- Fix a comment in the rseq registration rseq_size bound check code
- Fix a legacy RSEQ ABI quirk that handled 32-byte area sizes
differently, which special size we now reached naturally and
want to avoid. The visible ugliness of the new reserved field
will be avoided the next time the RSEQ area is extended.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-urgent-2026-03-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
- Fix zero_vruntime tracking when there's a single task running
- Fix slice protection logic
- Fix the ->vprot logic for reniced tasks
- Fix lag clamping in mixed slice workloads
- Fix objtool uaccess warning (and bug) in the
!CONFIG_RSEQ_SLICE_EXTENSION case caused by unexpected un-inlining,
which triggers with older compilers
- Fix a comment in the rseq registration rseq_size bound check code
- Fix a legacy RSEQ ABI quirk that handled 32-byte area sizes
differently, which special size we now reached naturally and want to
avoid. The visible ugliness of the new reserved field will be avoided
the next time the RSEQ area is extended.
* tag 'sched-urgent-2026-03-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
rseq: slice ext: Ensure rseq feature size differs from original rseq size
rseq: Clarify rseq registration rseq_size bound check comment
sched/core: Fix wakeup_preempt's next_class tracking
rseq: Mark rseq_arm_slice_extension_timer() __always_inline
sched/fair: Fix lag clamp
sched/eevdf: Update se->vprot in reweight_entity()
sched/fair: Only set slice protection at pick time
sched/fair: Fix zero_vruntime tracking
- Fix lock ordering bug found by lockdep in perf_event_wakeup()
- Fix uncore counter enumeration on Granite Rapids and Sierra Forest
- Fix perf_mmap() refcount bug found by Syzkaller
- Fix __perf_event_overflow() vs. perf_remove_from_context() race
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-urgent-2026-03-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf events fixes from Ingo Molnar:
- Fix lock ordering bug found by lockdep in perf_event_wakeup()
- Fix uncore counter enumeration on Granite Rapids and Sierra Forest
- Fix perf_mmap() refcount bug found by Syzkaller
- Fix __perf_event_overflow() vs perf_remove_from_context() race
* tag 'perf-urgent-2026-03-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Fix __perf_event_overflow() vs perf_remove_from_context() race
perf/core: Fix refcount bug and potential UAF in perf_mmap
perf/x86/intel/uncore: Add per-scheduler IMC CAS count events
perf/core: Fix invalid wait context in ctx_sched_in()
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Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Pull bpf fixes from Alexei Starovoitov:
- Fix alignment of arm64 JIT buffer to prevent atomic tearing (Fuad
Tabba)
- Fix invariant violation for single value tnums in the verifier
(Harishankar Vishwanathan, Paul Chaignon)
- Fix a bunch of issues found by ASAN in selftests/bpf (Ihor Solodrai)
- Fix race in devmpa and cpumap on PREEMPT_RT (Jiayuan Chen)
- Fix show_fdinfo of kprobe_multi when cookies are not present (Jiri
Olsa)
- Fix race in freeing special fields in BPF maps to prevent memory
leaks (Kumar Kartikeya Dwivedi)
- Fix OOB read in dmabuf_collector (T.J. Mercier)
* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: (36 commits)
selftests/bpf: Avoid simplification of crafted bounds test
selftests/bpf: Test refinement of single-value tnum
bpf: Improve bounds when tnum has a single possible value
bpf: Introduce tnum_step to step through tnum's members
bpf: Fix race in devmap on PREEMPT_RT
bpf: Fix race in cpumap on PREEMPT_RT
selftests/bpf: Add tests for special fields races
bpf: Retire rcu_trace_implies_rcu_gp() from local storage
bpf: Delay freeing fields in local storage
bpf: Lose const-ness of map in map_check_btf()
bpf: Register dtor for freeing special fields
selftests/bpf: Fix OOB read in dmabuf_collector
selftests/bpf: Fix a memory leak in xdp_flowtable test
bpf: Fix stack-out-of-bounds write in devmap
bpf: Fix kprobe_multi cookies access in show_fdinfo callback
bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing
selftests/bpf: Don't override SIGSEGV handler with ASAN
selftests/bpf: Check BPFTOOL env var in detect_bpftool_path()
selftests/bpf: Fix out-of-bounds array access bugs reported by ASAN
selftests/bpf: Fix array bounds warning in jit_disasm_helpers
...
We're hitting an invariant violation in Cilium that sometimes leads to
BPF programs being rejected and Cilium failing to start [1]. The
following extract from verifier logs shows what's happening:
from 201 to 236: R1=0 R6=ctx() R7=1 R9=scalar(smin=umin=smin32=umin32=3584,smax=umax=smax32=umax32=3840,var_off=(0xe00; 0x100)) R10=fp0
236: R1=0 R6=ctx() R7=1 R9=scalar(smin=umin=smin32=umin32=3584,smax=umax=smax32=umax32=3840,var_off=(0xe00; 0x100)) R10=fp0
; if (magic == MARK_MAGIC_HOST || magic == MARK_MAGIC_OVERLAY || magic == MARK_MAGIC_ENCRYPT) @ bpf_host.c:1337
236: (16) if w9 == 0xe00 goto pc+45 ; R9=scalar(smin=umin=smin32=umin32=3585,smax=umax=smax32=umax32=3840,var_off=(0xe00; 0x100))
237: (16) if w9 == 0xf00 goto pc+1
verifier bug: REG INVARIANTS VIOLATION (false_reg1): range bounds violation u64=[0xe01, 0xe00] s64=[0xe01, 0xe00] u32=[0xe01, 0xe00] s32=[0xe01, 0xe00] var_off=(0xe00, 0x0)
We reach instruction 236 with two possible values for R9, 0xe00 and
0xf00. This is perfectly reflected in the tnum, but of course the ranges
are less accurate and cover [0xe00; 0xf00]. Taking the fallthrough path
at instruction 236 allows the verifier to reduce the range to
[0xe01; 0xf00]. The tnum is however not updated.
With these ranges, at instruction 237, the verifier is not able to
deduce that R9 is always equal to 0xf00. Hence the fallthrough pass is
explored first, the verifier refines the bounds using the assumption
that R9 != 0xf00, and ends up with an invariant violation.
This pattern of impossible branch + bounds refinement is common to all
invariant violations seen so far. The long-term solution is likely to
rely on the refinement + invariant violation check to detect dead
branches, as started by Eduard. To fix the current issue, we need
something with less refactoring that we can backport.
This patch uses the tnum_step helper introduced in the previous patch to
detect the above situation. In particular, three cases are now detected
in the bounds refinement:
1. The u64 range and the tnum only overlap in umin.
u64: ---[xxxxxx]-----
tnum: --xx----------x-
2. The u64 range and the tnum only overlap in the maximum value
represented by the tnum, called tmax.
u64: ---[xxxxxx]-----
tnum: xx-----x--------
3. The u64 range and the tnum only overlap in between umin (excluded)
and umax.
u64: ---[xxxxxx]-----
tnum: xx----x-------x-
To detect these three cases, we call tnum_step(tnum, umin), which
returns the smallest member of the tnum greater than umin, called
tnum_next here. We're in case (1) if umin is part of the tnum and
tnum_next is greater than umax. We're in case (2) if umin is not part of
the tnum and tnum_next is equal to tmax. Finally, we're in case (3) if
umin is not part of the tnum, tnum_next is inferior or equal to umax,
and calling tnum_step a second time gives us a value past umax.
This change implements these three cases. With it, the above bytecode
looks as follows:
0: (85) call bpf_get_prandom_u32#7 ; R0=scalar()
1: (47) r0 |= 3584 ; R0=scalar(smin=0x8000000000000e00,umin=umin32=3584,smin32=0x80000e00,var_off=(0xe00; 0xfffffffffffff1ff))
2: (57) r0 &= 3840 ; R0=scalar(smin=umin=smin32=umin32=3584,smax=umax=smax32=umax32=3840,var_off=(0xe00; 0x100))
3: (15) if r0 == 0xe00 goto pc+2 ; R0=3840
4: (15) if r0 == 0xf00 goto pc+1
4: R0=3840
6: (95) exit
In addition to the new selftests, this change was also verified with
Agni [3]. For the record, the raw SMT is available at [4]. The property
it verifies is that: If a concrete value x is contained in all input
abstract values, after __update_reg_bounds, it will continue to be
contained in all output abstract values.
Link: https://github.com/cilium/cilium/issues/44216 [1]
Link: https://pchaigno.github.io/test-verifier-complexity.html [2]
Link: https://github.com/bpfverif/agni [3]
Link: https://pastebin.com/raw/naCfaqNx [4]
Fixes: 0df1a55afa ("bpf: Warn on internal verifier errors")
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Tested-by: Marco Schirrmeister <mschirrmeister@gmail.com>
Co-developed-by: Harishankar Vishwanathan <harishankar.vishwanathan@gmail.com>
Signed-off-by: Harishankar Vishwanathan <harishankar.vishwanathan@gmail.com>
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Link: https://lore.kernel.org/r/ef254c4f68be19bd393d450188946821c588565d.1772225741.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit introduces tnum_step(), a function that, when given t, and a
number z returns the smallest member of t larger than z. The number z
must be greater or equal to the smallest member of t and less than the
largest member of t.
The first step is to compute j, a number that keeps all of t's known
bits, and matches all unknown bits to z's bits. Since j is a member of
the t, it is already a candidate for result. However, we want our result
to be (minimally) greater than z.
There are only two possible cases:
(1) Case j <= z. In this case, we want to increase the value of j and
make it > z.
(2) Case j > z. In this case, we want to decrease the value of j while
keeping it > z.
(Case 1) j <= z
t = xx11x0x0
z = 10111101 (189)
j = 10111000 (184)
^
k
(Case 1.1) Let's first consider the case where j < z. We will address j
== z later.
Since z > j, there had to be a bit position that was 1 in z and a 0 in
j, beyond which all positions of higher significance are equal in j and
z. Further, this position could not have been unknown in a, because the
unknown positions of a match z. This position had to be a 1 in z and
known 0 in t.
Let k be position of the most significant 1-to-0 flip. In our example, k
= 3 (starting the count at 1 at the least significant bit). Setting (to
1) the unknown bits of t in positions of significance smaller than
k will not produce a result > z. Hence, we must set/unset the unknown
bits at positions of significance higher than k. Specifically, we look
for the next larger combination of 1s and 0s to place in those
positions, relative to the combination that exists in z. We can achieve
this by concatenating bits at unknown positions of t into an integer,
adding 1, and writing the bits of that result back into the
corresponding bit positions previously extracted from z.
>From our example, considering only positions of significance greater
than k:
t = xx..x
z = 10..1
+ 1
-----
11..0
This is the exact combination 1s and 0s we need at the unknown bits of t
in positions of significance greater than k. Further, our result must
only increase the value minimally above z. Hence, unknown bits in
positions of significance smaller than k should remain 0. We finally
have,
result = 11110000 (240)
(Case 1.2) Now consider the case when j = z, for example
t = 1x1x0xxx
z = 10110100 (180)
j = 10110100 (180)
Matching the unknown bits of the t to the bits of z yielded exactly z.
To produce a number greater than z, we must set/unset the unknown bits
in t, and *all* the unknown bits of t candidates for being set/unset. We
can do this similar to Case 1.1, by adding 1 to the bits extracted from
the masked bit positions of z. Essentially, this case is equivalent to
Case 1.1, with k = 0.
t = 1x1x0xxx
z = .0.1.100
+ 1
---------
.0.1.101
This is the exact combination of bits needed in the unknown positions of
t. After recalling the known positions of t, we get
result = 10110101 (181)
(Case 2) j > z
t = x00010x1
z = 10000010 (130)
j = 10001011 (139)
^
k
Since j > z, there had to be a bit position which was 0 in z, and a 1 in
j, beyond which all positions of higher significance are equal in j and
z. This position had to be a 0 in z and known 1 in t. Let k be the
position of the most significant 0-to-1 flip. In our example, k = 4.
Because of the 0-to-1 flip at position k, a member of t can become
greater than z if the bits in positions greater than k are themselves >=
to z. To make that member *minimally* greater than z, the bits in
positions greater than k must be exactly = z. Hence, we simply match all
of t's unknown bits in positions more significant than k to z's bits. In
positions less significant than k, we set all t's unknown bits to 0
to retain minimality.
In our example, in positions of greater significance than k (=4),
t=x000. These positions are matched with z (1000) to produce 1000. In
positions of lower significance than k, t=10x1. All unknown bits are set
to 0 to produce 1001. The final result is:
result = 10001001 (137)
This concludes the computation for a result > z that is a member of t.
The procedure for tnum_step() in this commit implements the idea
described above. As a proof of correctness, we verified the algorithm
against a logical specification of tnum_step. The specification asserts
the following about the inputs t, z and output res that:
1. res is a member of t, and
2. res is strictly greater than z, and
3. there does not exist another value res2 such that
3a. res2 is also a member of t, and
3b. res2 is greater than z
3c. res2 is smaller than res
We checked the implementation against this logical specification using
an SMT solver. The verification formula in SMTLIB format is available
at [1]. The verification returned an "unsat": indicating that no input
assignment exists for which the implementation and the specification
produce different outputs.
In addition, we also automatically generated the logical encoding of the
C implementation using Agni [2] and verified it against the same
specification. This verification also returned an "unsat", confirming
that the implementation is equivalent to the specification. The formula
for this check is also available at [3].
Link: https://pastebin.com/raw/2eRWbiit [1]
Link: https://github.com/bpfverif/agni [2]
Link: https://pastebin.com/raw/EztVbBJ2 [3]
Co-developed-by: Srinivas Narayana <srinivas.narayana@rutgers.edu>
Signed-off-by: Srinivas Narayana <srinivas.narayana@rutgers.edu>
Co-developed-by: Santosh Nagarakatte <santosh.nagarakatte@rutgers.edu>
Signed-off-by: Santosh Nagarakatte <santosh.nagarakatte@rutgers.edu>
Signed-off-by: Harishankar Vishwanathan <harishankar.vishwanathan@gmail.com>
Link: https://lore.kernel.org/r/93fdf71910411c0f19e282ba6d03b4c65f9c5d73.1772225741.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
On PREEMPT_RT kernels, the per-CPU xdp_dev_bulk_queue (bq) can be
accessed concurrently by multiple preemptible tasks on the same CPU.
The original code assumes bq_enqueue() and __dev_flush() run atomically
with respect to each other on the same CPU, relying on
local_bh_disable() to prevent preemption. However, on PREEMPT_RT,
local_bh_disable() only calls migrate_disable() (when
PREEMPT_RT_NEEDS_BH_LOCK is not set) and does not disable
preemption, which allows CFS scheduling to preempt a task during
bq_xmit_all(), enabling another task on the same CPU to enter
bq_enqueue() and operate on the same per-CPU bq concurrently.
This leads to several races:
1. Double-free / use-after-free on bq->q[]: bq_xmit_all() snapshots
cnt = bq->count, then iterates bq->q[0..cnt-1] to transmit frames.
If preempted after the snapshot, a second task can call bq_enqueue()
-> bq_xmit_all() on the same bq, transmitting (and freeing) the
same frames. When the first task resumes, it operates on stale
pointers in bq->q[], causing use-after-free.
2. bq->count and bq->q[] corruption: concurrent bq_enqueue() modifying
bq->count and bq->q[] while bq_xmit_all() is reading them.
3. dev_rx/xdp_prog teardown race: __dev_flush() clears bq->dev_rx and
bq->xdp_prog after bq_xmit_all(). If preempted between
bq_xmit_all() return and bq->dev_rx = NULL, a preempting
bq_enqueue() sees dev_rx still set (non-NULL), skips adding bq to
the flush_list, and enqueues a frame. When __dev_flush() resumes,
it clears dev_rx and removes bq from the flush_list, orphaning the
newly enqueued frame.
4. __list_del_clearprev() on flush_node: similar to the cpumap race,
both tasks can call __list_del_clearprev() on the same flush_node,
the second dereferences the prev pointer already set to NULL.
The race between task A (__dev_flush -> bq_xmit_all) and task B
(bq_enqueue -> bq_xmit_all) on the same CPU:
Task A (xdp_do_flush) Task B (ndo_xdp_xmit redirect)
---------------------- --------------------------------
__dev_flush(flush_list)
bq_xmit_all(bq)
cnt = bq->count /* e.g. 16 */
/* start iterating bq->q[] */
<-- CFS preempts Task A -->
bq_enqueue(dev, xdpf)
bq->count == DEV_MAP_BULK_SIZE
bq_xmit_all(bq, 0)
cnt = bq->count /* same 16! */
ndo_xdp_xmit(bq->q[])
/* frames freed by driver */
bq->count = 0
<-- Task A resumes -->
ndo_xdp_xmit(bq->q[])
/* use-after-free: frames already freed! */
Fix this by adding a local_lock_t to xdp_dev_bulk_queue and acquiring
it in bq_enqueue() and __dev_flush(). These paths already run under
local_bh_disable(), so use local_lock_nested_bh() which on non-RT is
a pure annotation with no overhead, and on PREEMPT_RT provides a
per-CPU sleeping lock that serializes access to the bq.
Fixes: 3253cb49cb ("softirq: Allow to drop the softirq-BKL lock on PREEMPT_RT")
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Link: https://lore.kernel.org/r/20260225121459.183121-3-jiayuan.chen@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
On PREEMPT_RT kernels, the per-CPU xdp_bulk_queue (bq) can be accessed
concurrently by multiple preemptible tasks on the same CPU.
The original code assumes bq_enqueue() and __cpu_map_flush() run
atomically with respect to each other on the same CPU, relying on
local_bh_disable() to prevent preemption. However, on PREEMPT_RT,
local_bh_disable() only calls migrate_disable() (when
PREEMPT_RT_NEEDS_BH_LOCK is not set) and does not disable
preemption, which allows CFS scheduling to preempt a task during
bq_flush_to_queue(), enabling another task on the same CPU to enter
bq_enqueue() and operate on the same per-CPU bq concurrently.
This leads to several races:
1. Double __list_del_clearprev(): after bq->count is reset in
bq_flush_to_queue(), a preempting task can call bq_enqueue() ->
bq_flush_to_queue() on the same bq when bq->count reaches
CPU_MAP_BULK_SIZE. Both tasks then call __list_del_clearprev()
on the same bq->flush_node, the second call dereferences the
prev pointer that was already set to NULL by the first.
2. bq->count and bq->q[] races: concurrent bq_enqueue() can corrupt
the packet queue while bq_flush_to_queue() is processing it.
The race between task A (__cpu_map_flush -> bq_flush_to_queue) and
task B (bq_enqueue -> bq_flush_to_queue) on the same CPU:
Task A (xdp_do_flush) Task B (cpu_map_enqueue)
---------------------- ------------------------
bq_flush_to_queue(bq)
spin_lock(&q->producer_lock)
/* flush bq->q[] to ptr_ring */
bq->count = 0
spin_unlock(&q->producer_lock)
bq_enqueue(rcpu, xdpf)
<-- CFS preempts Task A --> bq->q[bq->count++] = xdpf
/* ... more enqueues until full ... */
bq_flush_to_queue(bq)
spin_lock(&q->producer_lock)
/* flush to ptr_ring */
spin_unlock(&q->producer_lock)
__list_del_clearprev(flush_node)
/* sets flush_node.prev = NULL */
<-- Task A resumes -->
__list_del_clearprev(flush_node)
flush_node.prev->next = ...
/* prev is NULL -> kernel oops */
Fix this by adding a local_lock_t to xdp_bulk_queue and acquiring it
in bq_enqueue() and __cpu_map_flush(). These paths already run under
local_bh_disable(), so use local_lock_nested_bh() which on non-RT is
a pure annotation with no overhead, and on PREEMPT_RT provides a
per-CPU sleeping lock that serializes access to the bq.
To reproduce, insert an mdelay(100) between bq->count = 0 and
__list_del_clearprev() in bq_flush_to_queue(), then run reproducer
provided by syzkaller.
Fixes: 3253cb49cb ("softirq: Allow to drop the softirq-BKL lock on PREEMPT_RT")
Reported-by: syzbot+2b3391f44313b3983e91@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/69369331.a70a0220.38f243.009d.GAE@google.com/T/
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jiayuan Chen <jiayuan.chen@shopee.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Link: https://lore.kernel.org/r/20260225121459.183121-2-jiayuan.chen@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This assumption will always hold going forward, hence just remove the
various checks and assume it is true with a comment for the uninformed
reader.
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260227224806.646888-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Currently, when use_kmalloc_nolock is false, the freeing of fields for a
local storage selem is done eagerly before waiting for the RCU or RCU
tasks trace grace period to elapse. This opens up a window where the
program which has access to the selem can recreate the fields after the
freeing of fields is done eagerly, causing memory leaks when the element
is finally freed and returned to the kernel.
Make a few changes to address this. First, delay the freeing of fields
until after the grace periods have expired using a __bpf_selem_free_rcu
wrapper which is eventually invoked after transitioning through the
necessary number of grace period waits. Replace usage of the kfree_rcu
with call_rcu to be able to take a custom callback. Finally, care needs
to be taken to extend the rcu barriers for all cases, and not just when
use_kmalloc_nolock is true, as RCU and RCU tasks trace callbacks can be
in flight for either case and access the smap field, which is used to
obtain the BTF record to walk over special fields in the map value.
While we're at it, drop migrate_disable() from bpf_selem_free_rcu, since
migration should be disabled for RCU callbacks already.
Fixes: 9bac675e63 ("bpf: Postpone bpf_obj_free_fields to the rcu callback")
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260227224806.646888-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
BPF hash map may now use the map_check_btf() callback to decide whether
to set a dtor on its bpf_mem_alloc or not. Unlike C++ where members can
opt out of const-ness using mutable, we must lose the const qualifier on
the callback such that we can avoid the ugly cast. Make the change and
adjust all existing users, and lose the comment in hashtab.c.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260227224806.646888-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
There is a race window where BPF hash map elements can leak special
fields if the program with access to the map value recreates these
special fields between the check_and_free_fields done on the map value
and its eventual return to the memory allocator.
Several ways were explored prior to this patch, most notably [0] tried
to use a poison value to reject attempts to recreate special fields for
map values that have been logically deleted but still accessible to BPF
programs (either while sitting in the free list or when reused). While
this approach works well for task work, timers, wq, etc., it is harder
to apply the idea to kptrs, which have a similar race and failure mode.
Instead, we change bpf_mem_alloc to allow registering destructor for
allocated elements, such that when they are returned to the allocator,
any special fields created while they were accessible to programs in the
mean time will be freed. If these values get reused, we do not free the
fields again before handing the element back. The special fields thus
may remain initialized while the map value sits in a free list.
When bpf_mem_alloc is retired in the future, a similar concept can be
introduced to kmalloc_nolock-backed kmem_cache, paired with the existing
idea of a constructor.
Note that the destructor registration happens in map_check_btf, after
the BTF record is populated and (at that point) avaiable for inspection
and duplication. Duplication is necessary since the freeing of embedded
bpf_mem_alloc can be decoupled from actual map lifetime due to logic
introduced to reduce the cost of rcu_barrier()s in mem alloc free path in
9f2c6e96c6 ("bpf: Optimize rcu_barrier usage between hash map and bpf_mem_alloc.").
As such, once all callbacks are done, we must also free the duplicated
record. To remove dependency on the bpf_map itself, also stash the key
size of the map to obtain value from htab_elem long after the map is
gone.
[0]: https://lore.kernel.org/bpf/20260216131341.1285427-1-mykyta.yatsenko5@gmail.com
Fixes: 14a324f6a6 ("bpf: Wire up freeing of referenced kptr")
Fixes: 1bfbc267ec ("bpf: Enable bpf_timer and bpf_wq in any context")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: syzbot@syzkaller.appspotmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260227224806.646888-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Even privileged services should not necessarily be able to see other
privileged service's namespaces so they can't leak information to each
other. Use may_see_all_namespaces() helper that centralizes this policy
until the nstree adapts.
Link: https://patch.msgid.link/20260226-work-visibility-fixes-v1-3-d2c2853313bd@kernel.org
Fixes: 76b6f5dfb3 ("nstree: add listns()")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Cc: stable@kernel.org # v6.19+
Signed-off-by: Christian Brauner <brauner@kernel.org>
Even privileged services should not necessarily be able to see other
privileged service's namespaces so they can't leak information to each
other. Use may_see_all_namespaces() helper that centralizes this policy
until the nstree adapts.
Link: https://patch.msgid.link/20260226-work-visibility-fixes-v1-1-d2c2853313bd@kernel.org
Fixes: a1d220d9da ("nsfs: iterate through mount namespaces")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Cc: stable@kernel.org # v6.12+
Signed-off-by: Christian Brauner <brauner@kernel.org>
All are singletons - please see the changelogs for details.
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Merge tag 'mm-hotfixes-stable-2026-02-26-14-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"12 hotfixes. 7 are cc:stable. 8 are for MM.
All are singletons - please see the changelogs for details"
* tag 'mm-hotfixes-stable-2026-02-26-14-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
MAINTAINERS: update Yosry Ahmed's email address
mailmap: add entry for Daniele Alessandrelli
mm: fix NULL NODE_DATA dereference for memoryless nodes on boot
mm/tracing: rss_stat: ensure curr is false from kthread context
mm/kfence: fix KASAN hardware tag faults during late enablement
mm/damon/core: disallow non-power of two min_region_sz
Squashfs: check metadata block offset is within range
MAINTAINERS, mailmap: update e-mail address for Vlastimil Babka
liveupdate: luo_file: remember retrieve() status
mm: thp: deny THP for files on anonymous inodes
mm: change vma_alloc_folio_noprof() macro to inline function
mm/kfence: disable KFENCE upon KASAN HW tags enablement
A set of two fixes for DMA-mapping subsystem for the recently merged API
rework (Jiri Pirko and Stian Halseth).
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Merge tag 'dma-mapping-7.0-2026-02-26' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux
Pull dma-mapping fixes from Marek Szyprowski:
"Two DMA-mapping fixes for the recently merged API rework (Jiri Pirko
and Stian Halseth)"
* tag 'dma-mapping-7.0-2026-02-26' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
sparc: Fix page alignment in dma mapping
dma-mapping: avoid random addr value print out on error path
SCX_EFLAG_INITIALIZED is the sole member of enum scx_exit_flags with no
explicit value, so the compiler assigns it 0. This makes the bitwise OR
in scx_ops_init() a no-op:
sch->exit_info->flags |= SCX_EFLAG_INITIALIZED; /* |= 0 */
As a result, BPF schedulers cannot distinguish whether ops.init()
completed successfully by inspecting exit_info->flags.
Assign the value 1LLU << 0 so the flag is actually set.
Fixes: f3aec2adce ("sched_ext: Add SCX_EFLAG_INITIALIZED to indicate successful ops.init()")
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
get_upper_ifindexes() iterates over all upper devices and writes their
indices into an array without checking bounds.
Also the callers assume that the max number of upper devices is
MAX_NEST_DEV and allocate excluded_devices[1+MAX_NEST_DEV] on the stack,
but that assumption is not correct and the number of upper devices could
be larger than MAX_NEST_DEV (e.g., many macvlans), causing a
stack-out-of-bounds write.
Add a max parameter to get_upper_ifindexes() to avoid the issue.
When there are too many upper devices, return -EOVERFLOW and abort the
redirect.
To reproduce, create more than MAX_NEST_DEV(8) macvlans on a device with
an XDP program attached using BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS.
Then send a packet to the device to trigger the XDP redirect path.
Reported-by: syzbot+10cc7f13760b31bd2e61@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/698c4ce3.050a0220.340abe.000b.GAE@google.com/T/
Fixes: aeea1b86f9 ("bpf, devmap: Exclude XDP broadcast to master device")
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Kohei Enju <kohei@enjuk.jp>
Link: https://lore.kernel.org/r/20260225053506.4738-1-kohei@enjuk.jp
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
- Fix pointer-to-array allocation types for ubd and kcsan
- Force size overflow helpers to __always_inline
- Bump __builtin_counted_by_ref to Clang 22.1 from 22.0 (Nathan Chancellor)
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Merge tag 'kmalloc_obj-v7.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull kmalloc_obj fixes from Kees Cook:
- Fix pointer-to-array allocation types for ubd and kcsan
- Force size overflow helpers to __always_inline
- Bump __builtin_counted_by_ref to Clang 22.1 from 22.0 (Nathan Chancellor)
* tag 'kmalloc_obj-v7.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
kcsan: test: Adjust "expect" allocation type for kmalloc_obj
overflow: Make sure size helpers are always inlined
init/Kconfig: Adjust fixed clang version for __builtin_counted_by_ref
ubd: Use pointer-to-pointers for io_thread_req arrays
The call to kmalloc_obj(observed.lines) returns "char (*)[3][512]",
a pointer to the whole 2D array. But "expect" wants to be "char (*)[512]",
the decayed pointer type, as if it were observed.lines itself (though
without the "3" bounds). This produces the following build error:
../kernel/kcsan/kcsan_test.c: In function '__report_matches':
../kernel/kcsan/kcsan_test.c:171:16: error: assignment to 'char (*)[512]' from incompatible pointer type 'char (*)[3][512]'
[-Wincompatible-pointer-types]
171 | expect = kmalloc_obj(observed.lines);
| ^
Instead of changing the "expect" type to "char (*)[3][512]" and
requiring a dereference at each use (e.g. "(expect*)[0]"), just
explicitly cast the return to the desired type.
Note that I'm intentionally not switching back to byte-based "kmalloc"
here because I cannot find a way for the Coccinelle script (which will
be used going forward to catch future conversions) to exclude this case.
Tested with:
$ ./tools/testing/kunit/kunit.py run \
--kconfig_add CONFIG_DEBUG_KERNEL=y \
--kconfig_add CONFIG_KCSAN=y \
--kconfig_add CONFIG_KCSAN_KUNIT_TEST=y \
--arch=x86_64 --qemu_args '-smp 2' kcsan
Reported-by: Nathan Chancellor <nathan@kernel.org>
Fixes: 69050f8d6d ("treewide: Replace kmalloc with kmalloc_obj for non-scalar types")
Signed-off-by: Kees Cook <kees@kernel.org>
Guillaume reported crashes via corrupted RCU callback function pointers
during KUnit testing. The crash was traced back to the pidfs rhashtable
conversion which replaced the 24-byte rb_node with an 8-byte rhash_head
in struct pid, shrinking it from 160 to 144 bytes.
struct kthread (without CONFIG_BLK_CGROUP) is also 144 bytes. With
CONFIG_SLAB_MERGE_DEFAULT and SLAB_HWCACHE_ALIGN both round up to
192 bytes and share the same slab cache. struct pid.rcu.func and
struct kthread.affinity_node both sit at offset 0x78.
When a kthread exits via make_task_dead() it bypasses kthread_exit() and
misses the affinity_node cleanup. free_kthread_struct() frees the memory
while the node is still linked into the global kthread_affinity_list. A
subsequent list_del() by another kthread writes through dangling list
pointers into the freed and reused memory, corrupting the pid's
rcu.func pointer.
Instead of patching free_kthread_struct() to handle the missed cleanup,
consolidate all kthread exit paths. Turn kthread_exit() into a macro
that calls do_exit() and add kthread_do_exit() which is called from
do_exit() for any task with PF_KTHREAD set. This guarantees that
kthread-specific cleanup always happens regardless of the exit path -
make_task_dead(), direct do_exit(), or kthread_exit().
Replace __to_kthread() with a new tsk_is_kthread() accessor in the
public header. Export do_exit() since module code using the
kthread_exit() macro now needs it directly.
Reported-by: Guillaume Tucker <gtucker@gtucker.io>
Tested-by: Guillaume Tucker <gtucker@gtucker.io>
Tested-by: Mark Brown <broonie@kernel.org>
Tested-by: David Gow <davidgow@google.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/all/20260224-mittlerweile-besessen-2738831ae7f6@brauner
Co-developed-by: Linus Torvalds <torvalds@linux-foundation.org>
Fixes: 4d13f4304f ("kthread: Implement preferred affinity")
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
scx_idle_node_masks is allocated with num_possible_nodes() elements but
indexed by NUMA node IDs via for_each_node(). On systems with
non-contiguous NUMA node numbering (e.g. nodes 0 and 4), node IDs can
exceed the array size, causing out-of-bounds memory corruption.
Use nr_node_ids instead, which represents the maximum node ID range and
is the correct size for arrays indexed by node ID.
Fixes: 7c60329e3521 ("sched_ext: Add NUMA-awareness to the default idle selection policy")
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Please consider pulling these changes from the signed vfs-7.0-rc2.fixes tag.
Thanks!
Christian
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Merge tag 'vfs-7.0-rc2.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs fixes from Christian Brauner:
- Fix an uninitialized variable in file_getattr().
The flags_valid field wasn't initialized before calling
vfs_fileattr_get(), triggering KMSAN uninit-value reports in fuse
- Fix writeback wakeup and logging timeouts when DETECT_HUNG_TASK is
not enabled.
sysctl_hung_task_timeout_secs is 0 in that case causing spurious
"waiting for writeback completion for more than 1 seconds" warnings
- Fix a null-ptr-deref in do_statmount() when the mount is internal
- Add missing kernel-doc description for the @private parameter in
iomap_readahead()
- Fix mount namespace creation to hold namespace_sem across the mount
copy in create_new_namespace().
The previous drop-and-reacquire pattern was fragile and failed to
clean up mount propagation links if the real rootfs was a shared or
dependent mount
- Fix /proc mount iteration where m->index wasn't updated when
m->show() overflows, causing a restart to repeatedly show the same
mount entry in a rapidly expanding mount table
- Return EFSCORRUPTED instead of ENOSPC in minix_new_inode() when the
inode number is out of range
- Fix unshare(2) when CLONE_NEWNS is set and current->fs isn't shared.
copy_mnt_ns() received the live fs_struct so if a subsequent
namespace creation failed the rollback would leave pwd and root
pointing to detached mounts. Always allocate a new fs_struct when
CLONE_NEWNS is requested
- fserror bug fixes:
- Remove the unused fsnotify_sb_error() helper now that all callers
have been converted to fserror_report_metadata
- Fix a lockdep splat in fserror_report() where igrab() takes
inode::i_lock which can be held in IRQ context.
Replace igrab() with a direct i_count bump since filesystems
should not report inodes that are about to be freed or not yet
exposed
- Handle error pointer in procfs for try_lookup_noperm()
- Fix an integer overflow in ep_loop_check_proc() where recursive calls
returning INT_MAX would overflow when +1 is added, breaking the
recursion depth check
- Fix a misleading break in pidfs
* tag 'vfs-7.0-rc2.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
pidfs: avoid misleading break
eventpoll: Fix integer overflow in ep_loop_check_proc()
proc: Fix pointer error dereference
fserror: fix lockdep complaint when igrabbing inode
fsnotify: drop unused helper
unshare: fix unshare_fs() handling
minix: Correct errno in minix_new_inode
namespace: fix proc mount iteration
mount: hold namespace_sem across copy in create_new_namespace()
iomap: Describe @private in iomap_readahead()
statmount: Fix the null-ptr-deref in do_statmount()
writeback: Fix wakeup and logging timeouts for !DETECT_HUNG_TASK
fs: init flags_valid before calling vfs_fileattr_get
Make sure that __perf_event_overflow() runs with IRQs disabled for all
possible callchains. Specifically the software events can end up running
it with only preemption disabled.
This opens up a race vs perf_event_exit_event() and friends that will go
and free various things the overflow path expects to be present, like
the BPF program.
Fixes: 592903cdcb ("perf_counter: add an event_list")
Reported-by: Simond Hu <cmdhh1767@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Simond Hu <cmdhh1767@gmail.com>
Link: https://patch.msgid.link/20260224122909.GV1395416@noisy.programming.kicks-ass.net
scx_claim_exit() atomically sets exit_kind, which prevents scx_error() from
triggering further error handling. After claiming exit, the caller must kick
the helper kthread work which initiates bypass mode and teardown.
If the calling task gets preempted between claiming exit and kicking the
helper work, and the BPF scheduler fails to schedule it back (since error
handling is now disabled), the helper work is never queued, bypass mode
never activates, tasks stop being dispatched, and the system wedges.
Disable preemption across scx_claim_exit() and the subsequent work kicking
in all callers - scx_disable() and scx_vexit(). Add
lockdep_assert_preemption_disabled() to scx_claim_exit() to enforce the
requirement.
Fixes: f0e1a0643a ("sched_ext: Implement BPF extensible scheduler class")
Cc: stable@vger.kernel.org # v6.12+
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
LUO keeps track of successful retrieve attempts on a LUO file. It does so
to avoid multiple retrievals of the same file. Multiple retrievals cause
problems because once the file is retrieved, the serialized data
structures are likely freed and the file is likely in a very different
state from what the code expects.
The retrieve boolean in struct luo_file keeps track of this, and is passed
to the finish callback so it knows what work was already done and what it
has left to do.
All this works well when retrieve succeeds. When it fails,
luo_retrieve_file() returns the error immediately, without ever storing
anywhere that a retrieve was attempted or what its error code was. This
results in an errored LIVEUPDATE_SESSION_RETRIEVE_FD ioctl to userspace,
but nothing prevents it from trying this again.
The retry is problematic for much of the same reasons listed above. The
file is likely in a very different state than what the retrieve logic
normally expects, and it might even have freed some serialization data
structures. Attempting to access them or free them again is going to
break things.
For example, if memfd managed to restore 8 of its 10 folios, but fails on
the 9th, a subsequent retrieve attempt will try to call
kho_restore_folio() on the first folio again, and that will fail with a
warning since it is an invalid operation.
Apart from the retry, finish() also breaks. Since on failure the
retrieved bool in luo_file is never touched, the finish() call on session
close will tell the file handler that retrieve was never attempted, and it
will try to access or free the data structures that might not exist, much
in the same way as the retry attempt.
There is no sane way of attempting the retrieve again. Remember the error
retrieve returned and directly return it on a retry. Also pass this
status code to finish() so it can make the right decision on the work it
needs to do.
This is done by changing the bool to an integer. A value of 0 means
retrieve was never attempted, a positive value means it succeeded, and a
negative value means it failed and the error code is the value.
Link: https://lkml.kernel.org/r/20260216132221.987987-1-pratyush@kernel.org
Fixes: 7c722a7f44 ("liveupdate: luo_file: implement file systems callbacks")
Signed-off-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
The current cpuset partition code is able to dynamically update
the sched domains of a running system and the corresponding
HK_TYPE_DOMAIN housekeeping cpumask to perform what is essentially the
"isolcpus=domain,..." boot command line feature at run time.
The housekeeping cpumask update requires flushing a number of different
workqueues which may not be safe with cpus_read_lock() held as the
workqueue flushing code may acquire cpus_read_lock() or acquiring locks
which have locking dependency with cpus_read_lock() down the chain. Below
is an example of such circular locking problem.
======================================================
WARNING: possible circular locking dependency detected
6.18.0-test+ #2 Tainted: G S
------------------------------------------------------
test_cpuset_prs/10971 is trying to acquire lock:
ffff888112ba4958 ((wq_completion)sync_wq){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x7a/0x180
but task is already holding lock:
ffffffffae47f450 (cpuset_mutex){+.+.}-{4:4}, at: cpuset_partition_write+0x85/0x130
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #4 (cpuset_mutex){+.+.}-{4:4}:
-> #3 (cpu_hotplug_lock){++++}-{0:0}:
-> #2 (rtnl_mutex){+.+.}-{4:4}:
-> #1 ((work_completion)(&arg.work)){+.+.}-{0:0}:
-> #0 ((wq_completion)sync_wq){+.+.}-{0:0}:
Chain exists of:
(wq_completion)sync_wq --> cpu_hotplug_lock --> cpuset_mutex
5 locks held by test_cpuset_prs/10971:
#0: ffff88816810e440 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0xf9/0x1d0
#1: ffff8891ab620890 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x260/0x5f0
#2: ffff8890a78b83e8 (kn->active#187){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2b6/0x5f0
#3: ffffffffadf32900 (cpu_hotplug_lock){++++}-{0:0}, at: cpuset_partition_write+0x77/0x130
#4: ffffffffae47f450 (cpuset_mutex){+.+.}-{4:4}, at: cpuset_partition_write+0x85/0x130
Call Trace:
<TASK>
:
touch_wq_lockdep_map+0x93/0x180
__flush_workqueue+0x111/0x10b0
housekeeping_update+0x12d/0x2d0
update_parent_effective_cpumask+0x595/0x2440
update_prstate+0x89d/0xce0
cpuset_partition_write+0xc5/0x130
cgroup_file_write+0x1a5/0x680
kernfs_fop_write_iter+0x3df/0x5f0
vfs_write+0x525/0xfd0
ksys_write+0xf9/0x1d0
do_syscall_64+0x95/0x520
entry_SYSCALL_64_after_hwframe+0x76/0x7e
To avoid such a circular locking dependency problem, we have to
call housekeeping_update() without holding the cpus_read_lock() and
cpuset_mutex. The current set of wq's flushed by housekeeping_update()
may not have work functions that call cpus_read_lock() directly,
but we are likely to extend the list of wq's that are flushed in the
future. Moreover, the current set of work functions may hold locks that
may have cpu_hotplug_lock down the dependency chain.
So housekeeping_update() is now called after releasing cpus_read_lock
and cpuset_mutex at the end of a cpuset operation. These two locks are
then re-acquired later before calling rebuild_sched_domains_locked().
To enable mutual exclusion between the housekeeping_update() call and
other cpuset control file write actions, a new top level cpuset_top_mutex
is introduced. This new mutex will be acquired first to allow sharing
variables used by both code paths. However, cpuset update from CPU
hotplug can still happen in parallel with the housekeeping_update()
call, though that should be rare in production environment.
As cpus_read_lock() is now no longer held when
tmigr_isolated_exclude_cpumask() is called, it needs to acquire it
directly.
The lockdep_is_cpuset_held() is also updated to return true if either
cpuset_top_mutex or cpuset_mutex is held.
Fixes: 03ff735101 ("cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The cpuset_handle_hotplug() may need to invoke housekeeping_update(),
for instance, when an isolated partition is invalidated because its
last active CPU has been put offline.
As we are going to enable dynamic update to the nozh_full housekeeping
cpumask (HK_TYPE_KERNEL_NOISE) soon with the help of CPU hotplug,
allowing the CPU hotplug path to call into housekeeping_update() directly
from update_isolation_cpumasks() will likely cause deadlock. So we
have to defer any call to housekeeping_update() after the CPU hotplug
operation has finished. This is now done via the workqueue where
the update_hk_sched_domains() function will be invoked via the
hk_sd_workfn().
An concurrent cpuset control file write may have executed the required
update_hk_sched_domains() function before the work function is called. So
the work function call may become a no-op when it is invoked.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
With the latest changes in sched/isolation.c, rebuild_sched_domains*()
requires the HK_TYPE_DOMAIN housekeeping cpumask to be properly
updated first, if needed, before the sched domains can be
rebuilt. So the two naturally fit together. Do that by creating a new
update_hk_sched_domains() helper to house both actions.
The name of the isolated_cpus_updating flag to control the
call to housekeeping_update() is now outdated. So change it to
update_housekeeping to better reflect its purpose. Also move the call
to update_hk_sched_domains() to the end of cpuset and hotplug operations
before releasing the cpuset_mutex.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
As cpuset is updating HK_TYPE_DOMAIN housekeeping mask when there is
a change in the set of isolated CPUs, making this change is now more
costly than before. Right now, the isolated_cpus_updating flag can be
set even if there is no real change in isolated_cpus. Put in additional
checks to make sure that isolated_cpus_updating is set only if there
is a real change in isolated_cpus.
Reviewed-by: Chen Ridong <chenridong@huaweicloud.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Clarify the locking rules associated with file level internal variables
inside the cpuset code. There is no functional change.
Reviewed-by: Chen Ridong <chenridong@huaweicloud.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Commit e2ffe502ba ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2")
incorrectly changed the 2nd parameter of cpuset_update_tasks_cpumask()
from tmp->new_cpus to cp->effective_cpus. This second parameter is just
a temporary cpumask for internal use. The cpuset_update_tasks_cpumask()
function was originally called update_tasks_cpumask() before commit
381b53c3b5 ("cgroup/cpuset: rename functions shared between v1
and v2").
This mistake can incorrectly change the effective_cpus of the
cpuset when it is the top_cpuset or in arm64 architecture where
task_cpu_possible_mask() may differ from cpu_possible_mask. So far
top_cpuset hasn't been passed to update_cpumasks_hier() yet, but arm64
arch can still be impacted. Fix it by reverting the incorrect change.
Fixes: e2ffe502ba ("cgroup/cpuset: Add cpuset.cpus.exclusive for v2")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The effective_xcpus of a cpuset can contain offline CPUs. In
partition_xcpus_del(), the xcpus parameter is incorrectly used as
a temporary cpumask to mask out offline CPUs. As xcpus can be the
effective_xcpus of a cpuset, this can result in unexpected changes
in that cpumask. Fix this problem by not making any changes to the
xcpus parameter.
Fixes: 11e5f407b6 ("cgroup/cpuset: Keep track of CPUs in isolated partitions")
Reviewed-by: Chen Ridong <chenridong@huaweicloud.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The module loader doesn't check for bounds of the ELF section index in
simplify_symbols():
for (i = 1; i < symsec->sh_size / sizeof(Elf_Sym); i++) {
const char *name = info->strtab + sym[i].st_name;
switch (sym[i].st_shndx) {
case SHN_COMMON:
[...]
default:
/* Divert to percpu allocation if a percpu var. */
if (sym[i].st_shndx == info->index.pcpu)
secbase = (unsigned long)mod_percpu(mod);
else
/** HERE --> **/ secbase = info->sechdrs[sym[i].st_shndx].sh_addr;
sym[i].st_value += secbase;
break;
}
}
A symbol with an out-of-bounds st_shndx value, for example 0xffff
(known as SHN_XINDEX or SHN_HIRESERVE), may cause a kernel panic:
BUG: unable to handle page fault for address: ...
RIP: 0010:simplify_symbols+0x2b2/0x480
...
Kernel panic - not syncing: Fatal exception
This can happen when module ELF is legitimately using SHN_XINDEX or
when it is corrupted.
Add a bounds check in simplify_symbols() to validate that st_shndx is
within the valid range before using it.
This issue was discovered due to a bug in llvm-objcopy, see relevant
discussion for details [1].
[1] https://lore.kernel.org/linux-modules/20251224005752.201911-1-ihor.solodrai@linux.dev/
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Reviewed-by: Daniel Gomez <da.gomez@samsung.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
This config option goes way back - it used to be an internal debug
option to random.c (at that point called DEBUG_RANDOM_BOOT), then was
renamed and exposed as a config option as CONFIG_WARN_UNSEEDED_RANDOM,
and then further renamed to the current CONFIG_WARN_ALL_UNSEEDED_RANDOM.
It was all done with the best of intentions: the more limited
rate-limited reports were reporting some cases, but if you wanted to see
all the gory details, you'd enable this "ALL" option.
However, it turns out - perhaps not surprisingly - that when people
don't care about and fix the first rate-limited cases, they most
certainly don't care about any others either, and so warning about all
of them isn't actually helping anything.
And the non-ratelimited reporting causes problems, where well-meaning
people enable debug options, but the excessive flood of messages that
nobody cares about will hide actual real information when things go
wrong.
I just got a kernel bug report (which had nothing to do with randomness)
where two thirds of the the truncated dmesg was just variations of
random: get_random_u32 called from __get_random_u32_below+0x10/0x70 with crng_init=0
and in the process early boot messages had been lost (in addition to
making the messages that _hadn't_ been lost harder to read).
The proper way to find these things for the hypothetical developer that
cares - if such a person exists - is almost certainly with boot time
tracing. That gives you the option to get call graphs etc too, which is
likely a requirement for fixing any problems anyway.
See Documentation/trace/boottime-trace.rst for that option.
And if we for some reason do want to re-introduce actual printing of
these things, it will need to have some uniqueness filtering rather than
this "just print it all" model.
Fixes: cc1e127bfa ("random: remove ratelimiting for in-kernel unseeded randomness")
Acked-by: Jason Donenfeld <Jason@zx2c4.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The module Kconfig file contains a set of options related to "Module
versioning support" (depends on MODVERSIONS) and "Module signature
verification" (depends on MODULE_SIG). The Kconfig tool automatically
creates submenus when an entry for a symbol is followed by consecutive
items that all depend on the symbol. However, this functionality doesn't
work for the mentioned module options. The MODVERSIONS options are
interleaved with ASM_MODVERSIONS, which has no 'depends on MODVERSIONS' but
instead uses 'default HAVE_ASM_MODVERSIONS && MODVERSIONS'. Similarly, the
MODULE_SIG options are interleaved by a comment warning not to forget
signing modules with scripts/sign-file, which uses the condition 'depends
on MODULE_SIG_FORCE && !MODULE_SIG_ALL'.
The result is that the options are confusingly shown when using
a menuconfig tool, as follows:
[*] Module versioning support
Module versioning implementation (genksyms (from source code)) --->
[ ] Extended Module Versioning Support
[*] Basic Module Versioning Support
[*] Source checksum for all modules
[*] Module signature verification
[ ] Require modules to be validly signed
[ ] Automatically sign all modules
Hash algorithm to sign modules (SHA-256) --->
Fix the issue by using if/endif to group related options together in
kernel/module/Kconfig, similarly to how the MODULE_DEBUG options are
already grouped. Note that the signing-related options depend on
'MODULE_SIG || IMA_APPRAISE_MODSIG', with the exception of
MODULE_SIG_FORCE, which is valid only for MODULE_SIG and is therefore kept
separately. For consistency, do the same for the MODULE_COMPRESS entries.
The options are then properly placed into submenus, as follows:
[*] Module versioning support
Module versioning implementation (genksyms (from source code)) --->
[ ] Extended Module Versioning Support
[*] Basic Module Versioning Support
[*] Source checksum for all modules
[*] Module signature verification
[ ] Require modules to be validly signed
[ ] Automatically sign all modules
Hash algorithm to sign modules (SHA-256) --->
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Reviewed-by: Daniel Gomez <da.gomez@samsung.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
In the error path of load_module(), under the free_module label, the
code calls lockdep_free_key_range() to release lock classes associated
with the MOD_DATA, MOD_RODATA and MOD_RO_AFTER_INIT module regions, and
subsequently invokes module_deallocate().
Since commit ac3b432839 ("module: replace module_layout with
module_memory"), the module_deallocate() function calls free_mod_mem(),
which releases the lock classes as well and considers all module
regions.
Attempting to free these classes twice is unnecessary. Remove the
redundant code in load_module().
Fixes: ac3b432839 ("module: replace module_layout with module_memory")
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Reviewed-by: Daniel Gomez <da.gomez@samsung.com>
Reviewed-by: Aaron Tomlin <atomlin@atomlin.com>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Syzkaller reported a refcount_t: addition on 0; use-after-free warning
in perf_mmap.
The issue is caused by a race condition between a failing mmap() setup
and a concurrent mmap() on a dependent event (e.g., using output
redirection).
In perf_mmap(), the ring_buffer (rb) is allocated and assigned to
event->rb with the mmap_mutex held. The mutex is then released to
perform map_range().
If map_range() fails, perf_mmap_close() is called to clean up.
However, since the mutex was dropped, another thread attaching to
this event (via inherited events or output redirection) can acquire
the mutex, observe the valid event->rb pointer, and attempt to
increment its reference count. If the cleanup path has already
dropped the reference count to zero, this results in a
use-after-free or refcount saturation warning.
Fix this by extending the scope of mmap_mutex to cover the
map_range() call. This ensures that the ring buffer initialization
and mapping (or cleanup on failure) happens atomically effectively,
preventing other threads from accessing a half-initialized or
dying ring buffer.
Closes: https://lore.kernel.org/oe-kbuild-all/202602020208.m7KIjdzW-lkp@intel.com/
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Haocheng Yu <yuhaocheng035@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260202162057.7237-1-yuhaocheng035@gmail.com
Lockdep found a bug in the event scheduling when a pinned event was
failed and wakes up the threads in the ring buffer like below.
It seems it should not grab a wait-queue lock under perf-context lock.
Let's do it with irq_work.
[ 39.913691] =============================
[ 39.914157] [ BUG: Invalid wait context ]
[ 39.914623] 6.15.0-next-20250530-next-2025053 #1 Not tainted
[ 39.915271] -----------------------------
[ 39.915731] repro/837 is trying to lock:
[ 39.916191] ffff88801acfabd8 (&event->waitq){....}-{3:3}, at: __wake_up+0x26/0x60
[ 39.917182] other info that might help us debug this:
[ 39.917761] context-{5:5}
[ 39.918079] 4 locks held by repro/837:
[ 39.918530] #0: ffffffff8725cd00 (rcu_read_lock){....}-{1:3}, at: __perf_event_task_sched_in+0xd1/0xbc0
[ 39.919612] #1: ffff88806ca3c6f8 (&cpuctx_lock){....}-{2:2}, at: __perf_event_task_sched_in+0x1a7/0xbc0
[ 39.920748] #2: ffff88800d91fc18 (&ctx->lock){....}-{2:2}, at: __perf_event_task_sched_in+0x1f9/0xbc0
[ 39.921819] #3: ffffffff8725cd00 (rcu_read_lock){....}-{1:3}, at: perf_event_wakeup+0x6c/0x470
Fixes: f4b07fd62d ("perf/core: Use POLLHUP for a pinned event in error")
Closes: https://lore.kernel.org/lkml/aD2w50VDvGIH95Pf@ly-workstation
Reported-by: "Lai, Yi" <yi1.lai@linux.intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: "Lai, Yi" <yi1.lai@linux.intel.com>
Link: https://patch.msgid.link/20250603045105.1731451-1-namhyung@kernel.org
Before rseq became extensible, its original size was 32 bytes even
though the active rseq area was only 20 bytes. This had the following
impact in terms of userspace ecosystem evolution:
* The GNU libc between 2.35 and 2.39 expose a __rseq_size symbol set
to 32, even though the size of the active rseq area is really 20.
* The GNU libc 2.40 changes this __rseq_size to 20, thus making it
express the active rseq area.
* Starting from glibc 2.41, __rseq_size corresponds to the
AT_RSEQ_FEATURE_SIZE from getauxval(3).
This means that users of __rseq_size can always expect it to
correspond to the active rseq area, except for the value 32, for
which the active rseq area is 20 bytes.
Exposing a 32 bytes feature size would make life needlessly painful
for userspace. Therefore, add a reserved field at the end of the
rseq area to bump the feature size to 33 bytes. This reserved field
is expected to be replaced with whatever field will come next,
expecting that this field will be larger than 1 byte.
The effect of this change is to increase the size from 32 to 64 bytes
before we actually have fields using that memory.
Clarify the allocation size and alignment requirements in the struct
rseq uapi comment.
Change the value returned by getauxval(AT_RSEQ_ALIGN) to return the
value of the active rseq area size rounded up to next power of 2, which
guarantees that the rseq structure will always be aligned on the nearest
power of two large enough to contain it, even as it grows. Change the
alignment check in the rseq registration accordingly.
This will minimize the amount of ABI corner-cases we need to document
and require userspace to play games with. The rule stays simple when
__rseq_size != 32:
#define rseq_field_available(field) (__rseq_size >= offsetofend(struct rseq_abi, field))
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260220200642.1317826-3-mathieu.desnoyers@efficios.com
The rseq registration validates that the rseq_size argument is greater
or equal to 32 (the original rseq size), but the comment associated with
this check does not clearly state this.
Clarify the comment to that effect.
Fixes: ee3e3ac05c ("rseq: Introduce extensible rseq ABI")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260220200642.1317826-2-mathieu.desnoyers@efficios.com
Kernel test robot reported that
tools/testing/selftests/kvm/hardware_disable_test was failing due to
commit 704069649b ("sched/core: Rework sched_class::wakeup_preempt()
and rq_modified_*()")
It turns out there were two related problems that could lead to a
missed preemption:
- when hitting newidle balance from the idle thread, it would elevate
rb->next_class from &idle_sched_class to &fair_sched_class, causing
later wakeup_preempt() calls to not hit the sched_class_above()
case, and not issue resched_curr().
Notably, this modification pattern should only lower the
next_class, and never raise it. Create two new helper functions to
wrap this.
- when doing schedule_idle(), it was possible to miss (re)setting
rq->next_class to &idle_sched_class, leading to the very same
problem.
Cc: Sean Christopherson <seanjc@google.com>
Fixes: 704069649b ("sched/core: Rework sched_class::wakeup_preempt() and rq_modified_*()")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202602122157.4e861298-lkp@intel.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260218163329.GQ1395416@noisy.programming.kicks-ass.net
Vincent reported that he was seeing undue lag clamping in a mixed
slice workload. Implement the max_slice tracking as per the todo
comment.
Fixes: 147f3efaa2 ("sched/fair: Implement an EEVDF-like scheduling policy")
Reported-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Tested-by: Shubhang Kaushik <shubhang@os.amperecomputing.com>
Link: https://patch.msgid.link/20250422101628.GA33555@noisy.programming.kicks-ass.net
Thomas Gleixner