Using single ftrace_ops for direct calls update instead of allocating
ftrace_ops object for each trampoline.
With single ftrace_ops object we can use update_ftrace_direct_* api
that allows multiple ip sites updates on single ftrace_ops object.
Adding HAVE_SINGLE_FTRACE_DIRECT_OPS config option to be enabled on
each arch that supports this.
At the moment we can enable this only on x86 arch, because arm relies
on ftrace_ops object representing just single trampoline image (stored
in ftrace_ops::direct_call). Archs that do not support this will continue
to use *_ftrace_direct api.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20251230145010.103439-10-jolsa@kernel.org
We are going to remove "ftrace_ops->private == bpf_trampoline" setup
in following changes.
Adding ip argument to ftrace_ops_func_t callback function, so we can
use it to look up the trampoline.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20251230145010.103439-9-jolsa@kernel.org
Adding update_ftrace_direct_mod function that modifies all entries
(ip -> direct) provided in hash argument to direct ftrace ops and
updates its attachments.
The difference to current modify_ftrace_direct is:
- hash argument that allows to modify multiple ip -> direct
entries at once
This change will allow us to have simple ftrace_ops for all bpf
direct interface users in following changes.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20251230145010.103439-7-jolsa@kernel.org
Adding update_ftrace_direct_del function that removes all entries
(ip -> addr) provided in hash argument to direct ftrace ops and
updates its attachments.
The difference to current unregister_ftrace_direct is
- hash argument that allows to unregister multiple ip -> direct
entries at once
- we can call update_ftrace_direct_del multiple times on the
same ftrace_ops object, becase we do not need to unregister
all entries at once, we can do it gradualy with the help of
ftrace_update_ops function
This change will allow us to have simple ftrace_ops for all bpf
direct interface users in following changes.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20251230145010.103439-6-jolsa@kernel.org
Adding update_ftrace_direct_add function that adds all entries
(ip -> addr) provided in hash argument to direct ftrace ops
and updates its attachments.
The difference to current register_ftrace_direct is
- hash argument that allows to register multiple ip -> direct
entries at once
- we can call update_ftrace_direct_add multiple times on the
same ftrace_ops object, becase after first registration with
register_ftrace_function_nolock, it uses ftrace_update_ops to
update the ftrace_ops object
This change will allow us to have simple ftrace_ops for all bpf
direct interface users in following changes.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20251230145010.103439-5-jolsa@kernel.org
We are going to use these functions in following changes.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20251230145010.103439-4-jolsa@kernel.org
Make alloc_and_copy_ftrace_hash to copy also direct address
for each hash entry.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20251230145010.103439-3-jolsa@kernel.org
At the moment the we allow the jmp attach only for ftrace_ops that
has FTRACE_OPS_FL_JMP set. This conflicts with following changes
where we use single ftrace_ops object for all direct call sites,
so all could be be attached via just call or jmp.
We already limit the jmp attach support with config option and bit
(LSB) set on the trampoline address. It turns out that's actually
enough to limit the jmp attach for architecture and only for chosen
addresses (with LSB bit set).
Each user of register_ftrace_direct or modify_ftrace_direct can set
the trampoline bit (LSB) to indicate it has to be attached by jmp.
The bpf trampoline generation code uses trampoline flags to generate
jmp-attach specific code and ftrace inner code uses the trampoline
bit (LSB) to handle return from jmp attachment, so there's no harm
to remove the FTRACE_OPS_FL_JMP bit.
The fexit/fmodret performance stays the same (did not drop),
current code:
fentry : 77.904 ± 0.546M/s
fexit : 62.430 ± 0.554M/s
fmodret : 66.503 ± 0.902M/s
with this change:
fentry : 80.472 ± 0.061M/s
fexit : 63.995 ± 0.127M/s
fmodret : 67.362 ± 0.175M/s
Fixes: 25e4e3565d ("ftrace: Introduce FTRACE_OPS_FL_JMP")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/bpf/20251230145010.103439-2-jolsa@kernel.org
If fsession exists, we will use the bit (1 << BPF_TRAMP_IS_RETURN_SHIFT)
in ((u64 *)ctx)[-1] to store the "is_return" flag.
The logic of bpf_session_is_return() for fsession is implemented in the
verifier by inline following code:
bool bpf_session_is_return(void *ctx)
{
return (((u64 *)ctx)[-1] >> BPF_TRAMP_IS_RETURN_SHIFT) & 1;
}
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Co-developed-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260124062008.8657-5-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add the function argument of "void *ctx" to bpf_session_cookie() and
bpf_session_is_return(), which is a preparation of the next patch.
The two kfunc is seldom used now, so it will not introduce much effect
to change their function prototype.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20260124062008.8657-4-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For now, ((u64 *)ctx)[-1] is used to store the nr_args in the trampoline.
However, 1 byte is enough to store such information. Therefore, we use
only the least significant byte of ((u64 *)ctx)[-1] to store the nr_args,
and reserve the rest for other usages.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Link: https://lore.kernel.org/r/20260124062008.8657-3-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
For now, bpf_get_func_arg() and bpf_get_func_arg_cnt() is not supported by
the BPF_TRACE_RAW_TP, which is not convenient to get the argument of the
tracepoint, especially for the case that the position of the arguments in
a tracepoint can change.
The target tracepoint BTF type id is specified during loading time,
therefore we can get the function argument count from the function
prototype instead of the stack.
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20260121044348.113201-2-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
After commit 37cce22dbd ("bpf: verifier: Refactor helper access type tracking"),
the verifier started relying on the access type flags in helper
function prototypes to perform memory access optimizations.
Currently, several helper functions utilizing ARG_PTR_TO_MEM lack the
corresponding MEM_RDONLY or MEM_WRITE flags. This omission causes the
verifier to incorrectly assume that the buffer contents are unchanged
across the helper call. Consequently, the verifier may optimize away
subsequent reads based on this wrong assumption, leading to correctness
issues.
For bpf_get_stack_proto_raw_tp, the original MEM_RDONLY was incorrect
since the helper writes to the buffer. Change it to ARG_PTR_TO_UNINIT_MEM
which correctly indicates write access to potentially uninitialized memory.
Similar issues were recently addressed for specific helpers in commit
ac44dcc788 ("bpf: Fix verifier assumptions of bpf_d_path's output buffer")
and commit 2eb7648558 ("bpf: Specify access type of bpf_sysctl_get_name args").
Fix these prototypes by adding the correct memory access flags.
Fixes: 37cce22dbd ("bpf: verifier: Refactor helper access type tracking")
Co-developed-by: Shuran Liu <electronlsr@gmail.com>
Signed-off-by: Shuran Liu <electronlsr@gmail.com>
Co-developed-by: Peili Gao <gplhust955@gmail.com>
Signed-off-by: Peili Gao <gplhust955@gmail.com>
Co-developed-by: Haoran Ni <haoran.ni.cs@gmail.com>
Signed-off-by: Haoran Ni <haoran.ni.cs@gmail.com>
Signed-off-by: Zesen Liu <ftyghome@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260120-helper_proto-v3-1-27b0180b4e77@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add __force annotations to casts that convert between __user and kernel
address spaces. These casts are intentional:
- In bpf_send_signal_common(), the value is stored in si_value.sival_ptr
which is typed as void __user *, but the value comes from a BPF
program parameter.
- In the bpf_*_dynptr() kfuncs, user pointers are cast to const void *
before being passed to copy helper functions that correctly handle
the user address space through copy_from_user variants.
Without __force, sparse reports:
warning: cast removes address space '__user' of expression
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260115184509.3585759-1-mykyta.yatsenko5@gmail.com
Closes: https://lore.kernel.org/oe-kbuild-all/202601131740.6C3BdBaB-lkp@intel.com/
Mahe reported issue with bpf_override_return helper not working when
executed from kprobe.multi bpf program on arm.
The problem is that on arm we use alternate storage for pt_regs object
that is passed to bpf_prog_run and if any register is changed (which
is the case of bpf_override_return) it's not propagated back to actual
pt_regs object.
Fixing this by introducing and calling ftrace_partial_regs_update function
to propagate the values of changed registers (ip and stack).
Reported-by: Mahe Tardy <mahe.tardy@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/bpf/20260112121157.854473-1-jolsa@kernel.org
Cross-merge BPF and other fixes after downstream PR.
No conflicts.
Adjacent:
Auto-merging MAINTAINERS
Auto-merging Makefile
Auto-merging kernel/bpf/verifier.c
Auto-merging kernel/sched/ext.c
Auto-merging mm/memcontrol.c
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The ftrace_dump_on_oops string is not used outside of trace.c so
make it static to avoid the export warning from sparse:
kernel/trace/trace.c:141:6: warning: symbol 'ftrace_dump_on_oops' was not declared. Should it be static?
Fixes: dd293df639 ("tracing: Move trace sysctls into trace.c")
Link: https://patch.msgid.link/20260106231054.84270-1-ben.dooks@codethink.co.uk
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
A bug was reported about an infinite recursion caused by tracing the rcu
events with the kernel stack trace trigger enabled. The stack trace code
called back into RCU which then called the stack trace again.
Expand the ftrace recursion protection to add a set of bits to protect
events from recursion. Each bit represents the context that the event is
in (normal, softirq, interrupt and NMI).
Have the stack trace code use the interrupt context to protect against
recursion.
Note, the bug showed an issue in both the RCU code as well as the tracing
stacktrace code. This only handles the tracing stack trace side of the
bug. The RCU fix will be handled separately.
Link: https://lore.kernel.org/all/20260102122807.7025fc87@gandalf.local.home/
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20260105203141.515cd49f@gandalf.local.home
Reported-by: Yao Kai <yaokai34@huawei.com>
Tested-by: Yao Kai <yaokai34@huawei.com>
Fixes: 5f5fa7ea89 ("rcu: Don't use negative nesting depth in __rcu_read_unlock()")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
When user resize all trace ring buffer through file 'buffer_size_kb',
then in ring_buffer_resize(), kernel allocates buffer pages for each
cpu in a loop.
If the kernel preemption model is PREEMPT_NONE and there are many cpus
and there are many buffer pages to be freed, it may not give up cpu
for a long time and finally cause a softlockup.
To avoid it, call cond_resched() after each cpu buffer free as Commit
f6bd2c9248 ("ring-buffer: Avoid softlockup in ring_buffer_resize()")
does.
Detailed call trace as follow:
rcu: INFO: rcu_sched self-detected stall on CPU
rcu: 24-....: (14837 ticks this GP) idle=521c/1/0x4000000000000000 softirq=230597/230597 fqs=5329
rcu: (t=15004 jiffies g=26003221 q=211022 ncpus=96)
CPU: 24 UID: 0 PID: 11253 Comm: bash Kdump: loaded Tainted: G EL 6.18.2+ #278 NONE
pc : arch_local_irq_restore+0x8/0x20
arch_local_irq_restore+0x8/0x20 (P)
free_frozen_page_commit+0x28c/0x3b0
__free_frozen_pages+0x1c0/0x678
___free_pages+0xc0/0xe0
free_pages+0x3c/0x50
ring_buffer_resize.part.0+0x6a8/0x880
ring_buffer_resize+0x3c/0x58
__tracing_resize_ring_buffer.part.0+0x34/0xd8
tracing_resize_ring_buffer+0x8c/0xd0
tracing_entries_write+0x74/0xd8
vfs_write+0xcc/0x288
ksys_write+0x74/0x118
__arm64_sys_write+0x24/0x38
Cc: <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251228065008.2396573-1-mawupeng1@huawei.com
Signed-off-by: Wupeng Ma <mawupeng1@huawei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
soft_mode is not read in the enable case, so drop the assignment.
Drop also the comment text that refers to the assignment and realign
the comment.
Cc: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Gabriele Paoloni <gpaoloni@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251226110531.4129794-1-Julia.Lawall@inria.fr
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
BPF programs detect recursion by doing atomic inc/dec on a per-cpu
active counter from the trampoline. Create two helpers for operations on
this active counter, this makes it easy to changes the recursion
detection logic in future.
This commit makes no functional changes.
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Link: https://lore.kernel.org/r/20251219184422.2899902-2-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
- Add Documentation/core-api/tracepoint.rst to TRACING in MAINTAINERS file
Updates to the tracepoint.rst document should be reviewed by the
tracing maintainers.
- Fix warning triggered by perf attaching to synthetic events
The synthetic events do not add a function to be registered when
perf attaches to them. This causes a warning when perf registers
a synthetic event and passes a NULL pointer to the tracepoint register
function. Ideally synthetic events should be updated to work with
perf, but as that's a feature and not a bug fix, simply now return
-ENODEV when perf tries to register an event that has a NULL pointer
for its function. This no longer causes a kernel warning and simply
causes the perf code to fail with an error message.
- Fix 32bit overflow in option flag test
The option's flags changed from 32 bits in size to 64 bits in size.
Fix one of the places that shift 1 by the option bit number to
to be 1ULL.
- Fix the output of printing the direct jmp functions
The enabled_functions that shows how functions are being attached by
ftrace wasn't updated to accommodate the new direct jmp trampolines
that set the LSB of the pointer, and outputs garbage. Update the
output to handle the direct jmp trampolines.
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Merge tag 'trace-v6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Add Documentation/core-api/tracepoint.rst to TRACING in MAINTAINERS
file
Updates to the tracepoint.rst document should be reviewed by the
tracing maintainers.
- Fix warning triggered by perf attaching to synthetic events
The synthetic events do not add a function to be registered when perf
attaches to them. This causes a warning when perf registers a
synthetic event and passes a NULL pointer to the tracepoint register
function.
Ideally synthetic events should be updated to work with perf, but as
that's a feature and not a bug fix, simply now return -ENODEV when
perf tries to register an event that has a NULL pointer for its
function. This no longer causes a kernel warning and simply causes
the perf code to fail with an error message.
- Fix 32bit overflow in option flag test
The option's flags changed from 32 bits in size to 64 bits in size.
Fix one of the places that shift 1 by the option bit number to to be
1ULL.
- Fix the output of printing the direct jmp functions
The enabled_functions that shows how functions are being attached by
ftrace wasn't updated to accommodate the new direct jmp trampolines
that set the LSB of the pointer, and outputs garbage. Update the
output to handle the direct jmp trampolines.
* tag 'trace-v6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ftrace: Fix address for jmp mode in t_show()
tracing: Fix UBSAN warning in __remove_instance()
tracing: Do not register unsupported perf events
MAINTAINERS: add tracepoint core-api doc files to TRACING
The address from ftrace_find_rec_direct() is printed directly in t_show().
This can mislead symbol offsets if it has the "jmp" bit in the last bit.
Fix this by printing the address that returned by ftrace_jmp_get().
Link: https://patch.msgid.link/20251217030053.80343-1-dongml2@chinatelecom.cn
Fixes: 25e4e3565d ("ftrace: Introduce FTRACE_OPS_FL_JMP")
Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Synthetic events currently do not have a function to register perf events.
This leads to calling the tracepoint register functions with a NULL
function pointer which triggers:
------------[ cut here ]------------
WARNING: kernel/tracepoint.c:175 at tracepoint_add_func+0x357/0x370, CPU#2: perf/2272
Modules linked in: kvm_intel kvm irqbypass
CPU: 2 UID: 0 PID: 2272 Comm: perf Not tainted 6.18.0-ftest-11964-ge022764176fc-dirty #323 PREEMPTLAZY
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.17.0-debian-1.17.0-1 04/01/2014
RIP: 0010:tracepoint_add_func+0x357/0x370
Code: 28 9c e8 4c 0b f5 ff eb 0f 4c 89 f7 48 c7 c6 80 4d 28 9c e8 ab 89 f4 ff 31 c0 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc <0f> 0b 49 c7 c6 ea ff ff ff e9 ee fe ff ff 0f 0b e9 f9 fe ff ff 0f
RSP: 0018:ffffabc0c44d3c40 EFLAGS: 00010246
RAX: 0000000000000001 RBX: ffff9380aa9e4060 RCX: 0000000000000000
RDX: 000000000000000a RSI: ffffffff9e1d4a98 RDI: ffff937fcf5fd6c8
RBP: 0000000000000001 R08: 0000000000000007 R09: ffff937fcf5fc780
R10: 0000000000000003 R11: ffffffff9c193910 R12: 000000000000000a
R13: ffffffff9e1e5888 R14: 0000000000000000 R15: ffffabc0c44d3c78
FS: 00007f6202f5f340(0000) GS:ffff93819f00f000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055d3162281a8 CR3: 0000000106a56003 CR4: 0000000000172ef0
Call Trace:
<TASK>
tracepoint_probe_register+0x5d/0x90
synth_event_reg+0x3c/0x60
perf_trace_event_init+0x204/0x340
perf_trace_init+0x85/0xd0
perf_tp_event_init+0x2e/0x50
perf_try_init_event+0x6f/0x230
? perf_event_alloc+0x4bb/0xdc0
perf_event_alloc+0x65a/0xdc0
__se_sys_perf_event_open+0x290/0x9f0
do_syscall_64+0x93/0x7b0
? entry_SYSCALL_64_after_hwframe+0x76/0x7e
? trace_hardirqs_off+0x53/0xc0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Instead, have the code return -ENODEV, which doesn't warn and has perf
error out with:
# perf record -e synthetic:futex_wait
Error:
The sys_perf_event_open() syscall returned with 19 (No such device) for event (synthetic:futex_wait).
"dmesg | grep -i perf" may provide additional information.
Ideally perf should support synthetic events, but for now just fix the
warning. The support can come later.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://patch.msgid.link/20251216182440.147e4453@gandalf.local.home
Fixes: 4b147936fa ("tracing: Add support for 'synthetic' events")
Reported-by: Ian Rogers <irogers@google.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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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 BPF builds due to -fms-extensions. selftests (Alexei
Starovoitov), bpftool (Quentin Monnet).
- Fix build of net/smc when CONFIG_BPF_SYSCALL=y, but CONFIG_BPF_JIT=n
(Geert Uytterhoeven)
- Fix livepatch/BPF interaction and support reliable unwinding through
BPF stack frames (Josh Poimboeuf)
- Do not audit capability check in arm64 JIT (Ondrej Mosnacek)
- Fix truncated dmabuf BPF iterator reads (T.J. Mercier)
- Fix verifier assumptions of bpf_d_path's output buffer (Shuran Liu)
- Fix warnings in libbpf when built with -Wdiscarded-qualifiers under
C23 (Mikhail Gavrilov)
* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests/bpf: add regression test for bpf_d_path()
bpf: Fix verifier assumptions of bpf_d_path's output buffer
selftests/bpf: Add test for truncated dmabuf_iter reads
bpf: Fix truncated dmabuf iterator reads
x86/unwind/orc: Support reliable unwinding through BPF stack frames
bpf: Add bpf_has_frame_pointer()
bpf, arm64: Do not audit capability check in do_jit()
libbpf: Fix -Wdiscarded-qualifiers under C23
bpftool: Fix build warnings due to MS extensions
net: smc: SMC_HS_CTRL_BPF should depend on BPF_JIT
selftests/bpf: Add -fms-extensions to bpf build flags
Commit 37cce22dbd ("bpf: verifier: Refactor helper access type
tracking") started distinguishing read vs write accesses performed by
helpers.
The second argument of bpf_d_path() is a pointer to a buffer that the
helper fills with the resulting path. However, its prototype currently
uses ARG_PTR_TO_MEM without MEM_WRITE.
Before 37cce22dbd, helper accesses were conservatively treated as
potential writes, so this mismatch did not cause issues. Since that
commit, the verifier may incorrectly assume that the buffer contents
are unchanged across the helper call and base its optimizations on this
wrong assumption. This can lead to misbehaviour in BPF programs that
read back the buffer, such as prefix comparisons on the returned path.
Fix this by marking the second argument of bpf_d_path() as
ARG_PTR_TO_MEM | MEM_WRITE so that the verifier correctly models the
write to the caller-provided buffer.
Fixes: 37cce22dbd ("bpf: verifier: Refactor helper access type tracking")
Co-developed-by: Zesen Liu <ftyg@live.com>
Signed-off-by: Zesen Liu <ftyg@live.com>
Co-developed-by: Peili Gao <gplhust955@gmail.com>
Signed-off-by: Peili Gao <gplhust955@gmail.com>
Co-developed-by: Haoran Ni <haoran.ni.cs@gmail.com>
Signed-off-by: Haoran Ni <haoran.ni.cs@gmail.com>
Signed-off-by: Shuran Liu <electronlsr@gmail.com>
Reviewed-by: Matt Bobrowski <mattbobrowski@google.com>
Link: https://lore.kernel.org/r/20251206141210.3148-2-electronlsr@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
- Fix accounting of stop_count in file release
On opening the trace file, if "pause-on-trace" option is set, it will
increment the stop_count. On file release, it checks if stop_count is set,
and if so it decrements it. Since this code was originally written, the
stop_count can be incremented by other use cases. This makes just checking
the stop_count not enough to know if it should be decremented.
Add a new iterator flag called "PAUSE" and have it set if the open
disables tracing and only decrement the stop_count if that flag is set on
close.
- Remove length field in trace_seq_printf() of print_synth_event()
When printing the synthetic event that has a static length array field,
the vsprintf() of the trace_seq_printf() triggered a "(efault)" in the
output. That's because the print_fmt replaced the "%.*s" with "%s" causing
the arguments to be off.
- Fix a bunch of typos
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Merge tag 'trace-v6.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Fix accounting of stop_count in file release
On opening the trace file, if "pause-on-trace" option is set, it will
increment the stop_count. On file release, it checks if stop_count is
set, and if so it decrements it. Since this code was originally
written, the stop_count can be incremented by other use cases. This
makes just checking the stop_count not enough to know if it should be
decremented.
Add a new iterator flag called "PAUSE" and have it set if the open
disables tracing and only decrement the stop_count if that flag is
set on close.
- Remove length field in trace_seq_printf() of print_synth_event()
When printing the synthetic event that has a static length array
field, the vsprintf() of the trace_seq_printf() triggered a
"(efault)" in the output. That's because the print_fmt replaced the
"%.*s" with "%s" causing the arguments to be off.
- Fix a bunch of typos
* tag 'trace-v6.19-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Fix typo in trace_seq.c
tracing: Fix typo in trace_probe.c
tracing: Fix multiple typos in trace_osnoise.c
tracing: Fix multiple typos in trace_events_user.c
tracing: Fix typo in trace_events_trigger.c
tracing: Fix typo in trace_events_hist.c
tracing: Fix typo in trace_events_filter.c
tracing: Fix multiple typos in trace_events.c
tracing: Fix multiple typos in trace.c
tracing: Fix typo in ring_buffer_benchmark.c
tracing: Fix multiple typos in ring_buffer.c
tracing: Fix typo in fprobe.c
tracing: Fix typo in fpgraph.c
tracing: Fix fixed array of synthetic event
tracing: Fix enabling of tracing on file release
The commit 4d38328eb4 ("tracing: Fix synth event printk format for str
fields") replaced "%.*s" with "%s" but missed removing the number size of
the dynamic and static strings. The commit e1a453a57b ("tracing: Do not
add length to print format in synthetic events") fixed the dynamic part
but did not fix the static part. That is, with the commands:
# echo 's:wake_lat char[] wakee; u64 delta;' >> /sys/kernel/tracing/dynamic_events
# echo 'hist:keys=pid:ts=common_timestamp.usecs if !(common_flags & 0x18)' > /sys/kernel/tracing/events/sched/sched_waking/trigger
# echo 'hist:keys=next_pid:delta=common_timestamp.usecs-$ts:onmatch(sched.sched_waking).trace(wake_lat,next_comm,$delta)' > /sys/kernel/tracing/events/sched/sched_switch/trigger
That caused the output of:
<idle>-0 [001] d..5. 193.428167: wake_lat: wakee=(efault)sshd-sessiondelta=155
sshd-session-879 [001] d..5. 193.811080: wake_lat: wakee=(efault)kworker/u34:5delta=58
<idle>-0 [002] d..5. 193.811198: wake_lat: wakee=(efault)bashdelta=91
The commit e1a453a57b fixed the part where the synthetic event had
"char[] wakee". But if one were to replace that with a static size string:
# echo 's:wake_lat char[16] wakee; u64 delta;' >> /sys/kernel/tracing/dynamic_events
Where "wakee" is defined as "char[16]" and not "char[]" making it a static
size, the code triggered the "(efaul)" again.
Remove the added STR_VAR_LEN_MAX size as the string is still going to be
nul terminated.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Douglas Raillard <douglas.raillard@arm.com>
Link: https://patch.msgid.link/20251204151935.5fa30355@gandalf.local.home
Fixes: e1a453a57b ("tracing: Do not add length to print format in synthetic events")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
The trace file will pause tracing if the tracing instance has the
"pause-on-trace" option is set. This happens when the file is opened, and
it is unpaused when the file is closed. When this was first added, there
was only one user that paused tracing. On open, the check to pause was:
if (!iter->snapshot && (tr->trace_flags & TRACE_ITER(PAUSE_ON_TRACE)))
Where if it is not the snapshot tracer and the "pause-on-trace" option is
set, then it increments a "stop_count" of the trace instance.
On close, the check is:
if (!iter->snapshot && tr->stop_count)
That is, if it is not the snapshot buffer and it was stopped, it will
re-enable tracing.
Now there's more places that stop tracing. This means, if something else
stops tracing the tr->stop_count will be non-zero, and that means if the
trace file is closed, it will decrement the stop_count even though it
never incremented it. This causes a warning because when the user that
stopped tracing enables it again, the stop_count goes below zero.
Instead of relying on the stop_count being set to know if the close of
the trace file should enable tracing again, add a new flag to the trace
iterator. The trace iterator is unique per open of the trace file, and if
the open stops tracing set the trace iterator PAUSE flag. On close, if the
PAUSE flag is set, then re-enable it again.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251202161751.24abaaf1@gandalf.local.home
Fixes: 06e0a548ba ("tracing: Do not disable tracing when reading the trace file")
Reported-by: syzbot+ccdec3bfe0beec58a38d@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/692f44a5.a70a0220.2ea503.00c8.GAE@google.com/
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
- fprobe: Performance enhancement of the fprobe using rhltable
. fprobe: use rhltable for fprobe_ip_table. The fprobe IP table has
been converted to use an rhltable for improved performance when
dealing with a large number of probed functions.
. Fix a suspicious RCU usage warning of the above change in the
fprobe entry handler.
. Remove an unused local variable of the above change.
. Fix to initialize fprobe_ip_table in core_initcall().
- fprobe: Performance optimization of fprobe by ftrace
. fprobe: Use ftrace instead of fgraph for entry only probes. This
avoids the unneeded overhead of fgraph stack setup.
. Also update fprobe selftest for entry-only probe.
. fprobe: Use ftrace only if CONFIG_DYNAMIC_FTRACE_WITH_ARGS or
WITH_REGS is defined.
- probes: Cleanup probe event subsystems.
. uprobe/eprobe: Allocate traceprobe_parse_context per probe instead
of each probe argument parsing. This reduce memory allocation/free
of temporary working memory.
. uprobes: Cleanup code using __free().
. eprobes: Cleanup code using __free().
. probes: Cleanup code using __free(trace_probe_log_clear) to clear
error log automatically.
. probes: Replace strcpy() with memcpy() in __trace_probe_log_err().
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Merge tag 'probes-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull probes updates from Masami Hiramatsu:
"fprobe performance enhancement using rhltable:
- use rhltable for fprobe_ip_table. The fprobe IP table has been
converted to use an rhltable for improved performance when dealing
with a large number of probed functions
- Fix a suspicious RCU usage warning of the above change in the
fprobe entry handler
- Remove an unused local variable of the above change
- Fix to initialize fprobe_ip_table in core_initcall()
Performance optimization of fprobe by ftrace:
- Use ftrace instead of fgraph for entry only probes. This avoids the
unneeded overhead of fgraph stack setup
- Also update fprobe selftest for entry-only probe
- fprobe: Use ftrace only if CONFIG_DYNAMIC_FTRACE_WITH_ARGS or
WITH_REGS is defined
Cleanup probe event subsystems:
- Allocate traceprobe_parse_context per probe instead of each probe
argument parsing. This reduce memory allocation/free of temporary
working memory
- Cleanup code using __free()
- Replace strcpy() with memcpy() in __trace_probe_log_err()"
* tag 'probes-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS
lib/test_fprobe: add testcase for mixed fprobe
tracing: fprobe: optimization for entry only case
tracing: fprobe: Fix to init fprobe_ip_table earlier
tracing: fprobe: Remove unused local variable
tracing: probes: Replace strcpy() with memcpy() in __trace_probe_log_err()
tracing: fprobe: fix suspicious rcu usage in fprobe_entry
tracing: uprobe: eprobes: Allocate traceprobe_parse_context per probe
tracing: uprobes: Cleanup __trace_uprobe_create() with __free()
tracing: eprobe: Cleanup eprobe event using __free()
tracing: probes: Use __free() for trace_probe_log
tracing: fprobe: use rhltable for fprobe_ip_table
The allocation of the per CPU buffer descriptor, the buffer page
descriptors and the buffer page data itself can be pretty ugly.
Add some helper macros and a function to have the code that allocates
buffer pages and such look a little cleaner.
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Merge tag 'trace-ringbuffer-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull trace ring-buffer cleanup from Steven Rostedt:
- Add helper functions for allocations
The allocation of the per CPU buffer descriptor, the buffer page
descriptors and the buffer page data itself can be pretty ugly.
Add some helper macros and a function to have the code that allocates
buffer pages and such look a little cleaner.
* tag 'trace-ringbuffer-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
ring-buffer: Add helper functions for allocations
- Adapt the ftracetest script to be run from a different folder
This uses the already existing OPT_TEST_DIR but extends it further to run
independent tests, then add an --rv flag to allow using the script for
testing RV (mostly) independently on ftrace.
- Add basic RV selftests in selftests/verification for more validations
Add more validations for available/enabled monitors and reactors. This
could have caught the bug introducing kernel panic solved above. Tests use
ftracetest.
- Convert react() function in reactor to use va_list directly
Use a central helper to handle the variadic arguments. Clean up macros
and mark functions as static.
- Add lockdep annotations to reactors to have lockdep complain of errors
If the reactors are called from improper context. Useful to develop new
reactors. This highlights a warning in the panic reactor that is related
to the printk subsystem and not to RV.
- Convert core RV code to use lock guards and __free helpers
This completely removes goto statements.
- Fix compilation if !CONFIG_RV_REACTORS
Fix the warning by keeping LTL monitor variable as always static.
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Merge tag 'trace-rv-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull runtime verifier updates from Steven Rostedt:
- Adapt the ftracetest script to be run from a different folder
This uses the already existing OPT_TEST_DIR but extends it further to
run independent tests, then add an --rv flag to allow using the
script for testing RV (mostly) independently on ftrace.
- Add basic RV selftests in selftests/verification for more validations
Add more validations for available/enabled monitors and reactors.
This could have caught the bug introducing kernel panic solved above.
Tests use ftracetest.
- Convert react() function in reactor to use va_list directly
Use a central helper to handle the variadic arguments. Clean up
macros and mark functions as static.
- Add lockdep annotations to reactors to have lockdep complain of
errors
If the reactors are called from improper context. Useful to develop
new reactors. This highlights a warning in the panic reactor that is
related to the printk subsystem and not to RV.
- Convert core RV code to use lock guards and __free helpers
This completely removes goto statements.
- Fix compilation if !CONFIG_RV_REACTORS
Fix the warning by keeping LTL monitor variable as always static.
* tag 'trace-rv-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
rv: Fix compilation if !CONFIG_RV_REACTORS
rv: Convert to use __free
rv: Convert to use lock guard
rv: Add explicit lockdep context for reactors
rv: Make rv_reacting_on() static
rv: Pass va_list to reactors
selftests/verification: Add initial RV tests
selftest/ftrace: Generalise ftracetest to use with RV
- Fix regression of pid filtering of function graph tracer
When the function graph tracer allowed multiple instances of
graph tracing using subops, the filtering by pid broke.
The ftrace_ops->private that was used for pid filtering wasn't
updated on creation.
The wrong function entry callback was used when pid filtering was
enabled when the function graph tracer started, which meant that
the pid filtering wasn't happening.
- Remove no longer needed ftrace_trace_task()
With PID filtering working via ftrace_pids_enabled() and fgraph_pid_func(),
the coarse-grained ftrace_trace_task() check in graph_entry() is obsolete.
It was only a fallback for uninitialized op->private (now fixed), and its
removal ensures consistent PID filtering with standard function tracing.
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Merge tag 'ftrace-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull ftrace updates from Steven Rostedt:
- Fix regression of pid filtering of function graph tracer
When the function graph tracer allowed multiple instances of graph
tracing using subops, the filtering by pid broke.
The ftrace_ops->private that was used for pid filtering wasn't
updated on creation.
The wrong function entry callback was used when pid filtering was
enabled when the function graph tracer started, which meant that
the pid filtering wasn't happening.
- Remove no longer needed ftrace_trace_task()
With PID filtering working via ftrace_pids_enabled() and
fgraph_pid_func(), the coarse-grained ftrace_trace_task()
check in graph_entry() is obsolete.
It was only a fallback for uninitialized op->private (now fixed),
and its removal ensures consistent PID filtering with standard
function tracing.
* tag 'ftrace-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
fgraph: Remove coarse PID filtering from graph_entry()
fgraph: Check ftrace_pids_enabled on registration for early filtering
fgraph: Initialize ftrace_ops->private for function graph ops
- Merge branch shared with kprobes on extending trace options
The trace options were defined by a 32 bit variable. This limits the
tracing instances to have a total of 32 different options. As that limit
has been hit, and more options are being added, increase the option mask
to a 64 bit number, doubling the number of options available.
As this is required for the kprobe topic branches as well as the tracing
topic branch, a separate branch was created and merged into both.
- Make trace_user_fault_read() available for the rest of tracing
The function trace_user_fault_read() is used by trace_marker file read to
allow reading user space to be done fast and without locking or
allocations. Make this available so that the system call trace events can
use it too.
- Have system call trace events read user space values
Now that the system call trace events callbacks are called in a faultable
context, take advantage of this and read the user space buffers for
various system calls. For example, show the path name of the openat system
call instead of just showing the pointer to that path name in user space.
Also show the contents of the buffer of the write system call. Several
system call trace events are updated to make tracing into a light weight
strace tool for all applications in the system.
- Update perf system call tracing to do the same
- And a config and syscall_user_buf_size file to control the size of the buffer
Limit the amount of data that can be read from user space. The default
size is 63 bytes but that can be expanded to 165 bytes.
- Allow the persistent ring buffer to print system calls normally
The persistent ring buffer prints trace events by their type and ignores
the print_fmt. This is because the print_fmt may change from kernel to
kernel. As the system call output is fixed by the system call ABI itself,
there's no reason to limit that. This makes reading the system call events
in the persistent ring buffer much nicer and easier to understand.
- Add options to show text offset to function profiler
The function profiler that counts the number of times a function is hit
currently lists all functions by its name and offset. But this becomes
ambiguous when there are several functions with the same name. Add a
tracing option that changes the output to be that of _text+offset
instead. Now a user space tool can use this information to map the
_text+offset to the unique function it is counting.
- Report bad dynamic event command
If a bad command is passed to the dynamic_events file, report it properly
in the error log.
- Clean up tracer options
Clean up the tracer option code a bit, by removing some useless code and
also using switch statements instead of a series of if statements.
- Have tracing options be instance specific
Tracers can have their own options (function tracer, irqsoff tracer,
function graph tracer, etc). But now that the same tracer can be enabled
in multiple trace instances, their options are still global. The API is
per instance, thus changing one affects other instances. This isn't even
consistent, as the option take affect differently depending on when an
tracer started in an instance. Make the options for instances only affect
the instance it is changed under.
- Optimize pid_list lock contention
Whenever the pid_list is read, it uses a spin lock. This happens at every
sched switch. Taking the lock at sched switch can be removed by instead
using a seqlock counter.
- Clean up the trace trigger structures
The trigger code uses two different structures to implement a single
tigger. This was due to trying to reuse code for the two different types
of triggers (always on trigger, and count limited trigger). But by adding
a single field to one structure, the other structure could be absorbed
into the first structure making he code easier to understand.
- Create a bulk garbage collector for trace triggers
If user space has triggers for several hundreds of events and then removes
them, it can take several seconds to complete. This is because each
removal calls the slow tracepoint_synchronize_unregister() that can take
hundreds of milliseconds to complete. Instead, create a helper thread that
will do the clean up. When a trigger is removed, it will create the
kthread if it isn't already created, and then add the trigger to a llist.
The kthread will take the items off the llist, call
tracepoint_synchronize_unregister(), and then remove the items it took
off. It will then check if there's more items to free before sleeping.
This makes user space removing all these triggers to finish in less than a
second.
- Allow function tracing of some of the tracing infrastructure code
Because the tracing code can cause recursion issues if it is traced by the
function tracer the entire tracing directory disables function tracing.
But not all of tracing causes issues if it is traced. Namely, the event
tracing code. Add a config that enables some of the tracing code to be
traced to help in debugging it. Note, when this is enabled, it does add
noise to general function tracing, especially if events are enabled as
well (which is a common case).
- Add boot-time backup instance for persistent buffer
The persistent ring buffer is used mostly for kernel crash analysis in the
field. One issue is that if there's a crash, the data in the persistent
ring buffer must be read before tracing can begin using it. This slows
down the boot process. Once tracing starts in the persistent ring buffer,
the old data must be freed and the addresses no longer match and old
events can't be in the buffer with new events.
Create a way to create a backup buffer that copies the persistent ring
buffer at boot up. Then after a crash, the always on tracer can begin
immediately as well as the normal boot process while the crash analysis
tooling uses the backup buffer. After the backup buffer is finished being
read, it can be removed.
- Enable function graph args and return address options at the same time
Currently the when reading of arguments in the function graph tracer is
enabled, the option to record the parent function in the entry event can
not be enabled. Update the code so that it can.
- Add new struct_offset() helper macro
Add a new macro that takes a pointer to a structure and a name of one of
its members and it will return the offset of that member. This allows the
ring buffer code to simplify the following:
From: size = struct_size(entry, buf, cnt - sizeof(entry->id));
To: size = struct_offset(entry, id) + cnt;
There should be other simplifications that this macro can help out with as
well.
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Merge tag 'trace-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing updates from Steven Rostedt:
- Extend tracing option mask to 64 bits
The trace options were defined by a 32 bit variable. This limits the
tracing instances to have a total of 32 different options. As that
limit has been hit, and more options are being added, increase the
option mask to a 64 bit number, doubling the number of options
available.
As this is required for the kprobe topic branches as well as the
tracing topic branch, a separate branch was created and merged into
both.
- Make trace_user_fault_read() available for the rest of tracing
The function trace_user_fault_read() is used by trace_marker file
read to allow reading user space to be done fast and without locking
or allocations. Make this available so that the system call trace
events can use it too.
- Have system call trace events read user space values
Now that the system call trace events callbacks are called in a
faultable context, take advantage of this and read the user space
buffers for various system calls. For example, show the path name of
the openat system call instead of just showing the pointer to that
path name in user space. Also show the contents of the buffer of the
write system call. Several system call trace events are updated to
make tracing into a light weight strace tool for all applications in
the system.
- Update perf system call tracing to do the same
- And a config and syscall_user_buf_size file to control the size of
the buffer
Limit the amount of data that can be read from user space. The
default size is 63 bytes but that can be expanded to 165 bytes.
- Allow the persistent ring buffer to print system calls normally
The persistent ring buffer prints trace events by their type and
ignores the print_fmt. This is because the print_fmt may change from
kernel to kernel. As the system call output is fixed by the system
call ABI itself, there's no reason to limit that. This makes reading
the system call events in the persistent ring buffer much nicer and
easier to understand.
- Add options to show text offset to function profiler
The function profiler that counts the number of times a function is
hit currently lists all functions by its name and offset. But this
becomes ambiguous when there are several functions with the same
name.
Add a tracing option that changes the output to be that of
'_text+offset' instead. Now a user space tool can use this
information to map the '_text+offset' to the unique function it is
counting.
- Report bad dynamic event command
If a bad command is passed to the dynamic_events file, report it
properly in the error log.
- Clean up tracer options
Clean up the tracer option code a bit, by removing some useless code
and also using switch statements instead of a series of if
statements.
- Have tracing options be instance specific
Tracers can have their own options (function tracer, irqsoff tracer,
function graph tracer, etc). But now that the same tracer can be
enabled in multiple trace instances, their options are still global.
The API is per instance, thus changing one affects other instances.
This isn't even consistent, as the option take affect differently
depending on when an tracer started in an instance. Make the options
for instances only affect the instance it is changed under.
- Optimize pid_list lock contention
Whenever the pid_list is read, it uses a spin lock. This happens at
every sched switch. Taking the lock at sched switch can be removed by
instead using a seqlock counter.
- Clean up the trace trigger structures
The trigger code uses two different structures to implement a single
tigger. This was due to trying to reuse code for the two different
types of triggers (always on trigger, and count limited trigger). But
by adding a single field to one structure, the other structure could
be absorbed into the first structure making he code easier to
understand.
- Create a bulk garbage collector for trace triggers
If user space has triggers for several hundreds of events and then
removes them, it can take several seconds to complete. This is
because each removal calls tracepoint_synchronize_unregister() that
can take hundreds of milliseconds to complete.
Instead, create a helper thread that will do the clean up. When a
trigger is removed, it will create the kthread if it isn't already
created, and then add the trigger to a llist. The kthread will take
the items off the llist, call tracepoint_synchronize_unregister(),
and then remove the items it took off. It will then check if there's
more items to free before sleeping.
This makes user space removing all these triggers to finish in less
than a second.
- Allow function tracing of some of the tracing infrastructure code
Because the tracing code can cause recursion issues if it is traced
by the function tracer the entire tracing directory disables function
tracing. But not all of tracing causes issues if it is traced.
Namely, the event tracing code. Add a config that enables some of the
tracing code to be traced to help in debugging it. Note, when this is
enabled, it does add noise to general function tracing, especially if
events are enabled as well (which is a common case).
- Add boot-time backup instance for persistent buffer
The persistent ring buffer is used mostly for kernel crash analysis
in the field. One issue is that if there's a crash, the data in the
persistent ring buffer must be read before tracing can begin using
it. This slows down the boot process. Once tracing starts in the
persistent ring buffer, the old data must be freed and the addresses
no longer match and old events can't be in the buffer with new
events.
Create a way to create a backup buffer that copies the persistent
ring buffer at boot up. Then after a crash, the always on tracer can
begin immediately as well as the normal boot process while the crash
analysis tooling uses the backup buffer. After the backup buffer is
finished being read, it can be removed.
- Enable function graph args and return address options at the same
time
Currently the when reading of arguments in the function graph tracer
is enabled, the option to record the parent function in the entry
event can not be enabled. Update the code so that it can.
- Add new struct_offset() helper macro
Add a new macro that takes a pointer to a structure and a name of one
of its members and it will return the offset of that member. This
allows the ring buffer code to simplify the following:
From: size = struct_size(entry, buf, cnt - sizeof(entry->id));
To: size = struct_offset(entry, id) + cnt;
There should be other simplifications that this macro can help out
with as well
* tag 'trace-v6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (42 commits)
overflow: Introduce struct_offset() to get offset of member
function_graph: Enable funcgraph-args and funcgraph-retaddr to work simultaneously
tracing: Add boot-time backup of persistent ring buffer
ftrace: Allow tracing of some of the tracing code
tracing: Use strim() in trigger_process_regex() instead of skip_spaces()
tracing: Add bulk garbage collection of freeing event_trigger_data
tracing: Remove unneeded event_mutex lock in event_trigger_regex_release()
tracing: Merge struct event_trigger_ops into struct event_command
tracing: Remove get_trigger_ops() and add count_func() from trigger ops
tracing: Show the tracer options in boot-time created instance
ftrace: Avoid redundant initialization in register_ftrace_direct
tracing: Remove unused variable in tracing_trace_options_show()
fgraph: Make fgraph_no_sleep_time signed
tracing: Convert function graph set_flags() to use a switch() statement
tracing: Have function graph tracer option sleep-time be per instance
tracing: Move graph-time out of function graph options
tracing: Have function graph tracer option funcgraph-irqs be per instance
trace/pid_list: optimize pid_list->lock contention
tracing: Have function graph tracer define options per instance
tracing: Have function tracer define options per instance
...
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Merge tag 'for-6.19/block-20251201' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux
Pull block updates from Jens Axboe:
- Fix head insertion for mq-deadline, a regression from when priority
support was added
- Series simplifying and improving the ublk user copy code
- Various ublk related cleanups
- Fixup REQ_NOWAIT handling in loop/zloop, clearing NOWAIT when the
request is punted to a thread for handling
- Merge and then later revert loop dio nowait support, as it ended up
causing excessive stack usage for when the inline issue code needs to
dip back into the full file system code
- Improve auto integrity code, making it less deadlock prone
- Speedup polled IO handling, but manually managing the hctx lookups
- Fixes for blk-throttle for SSD devices
- Small series with fixes for the S390 dasd driver
- Add support for caching zones, avoiding unnecessary report zone
queries
- MD pull requests via Yu:
- fix null-ptr-dereference regression for dm-raid0
- fix IO hang for raid5 when array is broken with IO inflight
- remove legacy 1s delay to speed up system shutdown
- change maintainer's email address
- data can be lost if array is created with different lbs devices,
fix this problem and record lbs of the array in metadata
- fix rcu protection for md_thread
- fix mddev kobject lifetime regression
- enable atomic writes for md-linear
- some cleanups
- bcache updates via Coly
- remove useless discard and cache device code
- improve usage of per-cpu workqueues
- Reorganize the IO scheduler switching code, fixing some lockdep
reports as well
- Improve the block layer P2P DMA support
- Add support to the block tracing code for zoned devices
- Segment calculation improves, and memory alignment flexibility
improvements
- Set of prep and cleanups patches for ublk batching support. The
actual batching hasn't been added yet, but helps shrink down the
workload of getting that patchset ready for 6.20
- Fix for how the ps3 block driver handles segments offsets
- Improve how block plugging handles batch tag allocations
- nbd fixes for use-after-free of the configuration on device clear/put
- Set of improvements and fixes for zloop
- Add Damien as maintainer of the block zoned device code handling
- Various other fixes and cleanups
* tag 'for-6.19/block-20251201' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (162 commits)
block/rnbd: correct all kernel-doc complaints
blk-mq: use queue_hctx in blk_mq_map_queue_type
md: remove legacy 1s delay in md_notify_reboot
md/raid5: fix IO hang when array is broken with IO inflight
md: warn about updating super block failure
md/raid0: fix NULL pointer dereference in create_strip_zones() for dm-raid
sbitmap: fix all kernel-doc warnings
ublk: add helper of __ublk_fetch()
ublk: pass const pointer to ublk_queue_is_zoned()
ublk: refactor auto buffer register in ublk_dispatch_req()
ublk: add `union ublk_io_buf` with improved naming
ublk: add parameter `struct io_uring_cmd *` to ublk_prep_auto_buf_reg()
kfifo: add kfifo_alloc_node() helper for NUMA awareness
blk-mq: fix potential uaf for 'queue_hw_ctx'
blk-mq: use array manage hctx map instead of xarray
ublk: prevent invalid access with DEBUG
s390/dasd: Use scnprintf() instead of sprintf()
s390/dasd: Move device name formatting into separate function
s390/dasd: Remove unnecessary debugfs_create() return checks
s390/dasd: Fix gendisk parent after copy pair swap
...
Jiri Olsa