Scheduler Kconfig space updates:
- Further consolidate configurable preemption modes: reduce
the number of architectures that are allowed to offer
PREEMPT_NONE and PREEMPT_VOLUNTARY, reducing the number
of preemption models from four to just two: 'full' and 'lazy'
on up-to-date architectures (arm64, loongarch, powerpc,
riscv, s390, x86).
None and voluntary are only available as legacy features
on platforms that don't implement lazy preemption yet,
or which don't even support preemption.
The goal is to eventually remove cond_resched() and
voluntary preemption altogether.
(Peter Zijlstra)
RSEQ based 'scheduler time slice extension' support:
This allows a thread to request a time slice extension when it
enters a critical section to avoid contention on a resource when
the thread is scheduled out inside of the critical section.
- Add fields and constants for time slice extension
- Provide static branch for time slice extensions
- Add statistics for time slice extensions
- Add prctl() to enable time slice extensions
- Implement sys_rseq_slice_yield()
- Implement syscall entry work for time slice extensions
- Implement time slice extension enforcement timer
- Reset slice extension when scheduled
- Implement rseq_grant_slice_extension()
- entry: Hook up rseq time slice extension
- selftests: Implement time slice extension test
(Thomas Gleixner)
- Allow registering RSEQ with slice extension
- Move slice_ext_nsec to debugfs
- Lower default slice extension
- selftests/rseq: Add rseq slice histogram script
(Peter Zijlstra)
Scheduler performance/scalability improvements:
- Update rq->avg_idle when a task is moved to an idle CPU,
which improves the scalability of various workloads.
(Shubhang Kaushik)
- Reorder fields in 'struct rq' for better caching
(Blake Jones)
- Fair scheduler SMP NOHZ balancing code speedups:
- Move checking for nohz cpus after time check
- Change likelyhood of nohz.nr_cpus
- Remove nohz.nr_cpus and use weight of cpumask instead
(Shrikanth Hegde)
- Avoid false sharing for sched_clock_irqtime (Wangyang Guo)
- Drop useless cpumask_empty() in find_energy_efficient_cpu()
- Simplify task_numa_find_cpu()
- Use cpumask_weight_and() in sched_balance_find_dst_group()
(Yury Norov)
DL scheduler updates:
- Add a deadline server for sched_ext tasks (by Andrea Righi and
Joel Fernandes, with fixes by Peter Zijlstra)
RT scheduler updates:
- Skip currently executing CPU in rto_next_cpu() (Chen Jinghuang)
Entry code updates and performance improvements, which is part of the
scheduler tree in this cycle due to interdependencies with the RSEQ
based time slice extension work:
- Remove unused syscall argument from syscall_trace_enter()
- Rework syscall_exit_to_user_mode_work() for architecture reuse
- Add arch_ptrace_report_syscall_entry/exit()
- Inline syscall_exit_work() and syscall_trace_enter()
(Jinjie Ruan)
Scheduler core updates:
- Rework sched_class::wakeup_preempt() and rq_modified_*()
- Avoid rq->lock bouncing in sched_balance_newidle()
- Rename rcu_dereference_check_sched_domain() =>
rcu_dereference_sched_domain()
- <linux/compiler_types.h>: Add the __signed_scalar_typeof() helper
(Peter Zijlstra)
Fair scheduler updates/refactoring:
- Fold the sched_avg update
- Change rcu_dereference_check_sched_domain() to rcu-sched
- Switch to rcu_dereference_all()
- Remove superfluous rcu_read_lock()
- Limit hrtick work
(Peter Zijlstra)
- Join two #ifdef CONFIG_FAIR_GROUP_SCHED blocks
- Clean up comments in 'struct cfs_rq'
- Separate se->vlag from se->vprot
- Rename cfs_rq::avg_load to cfs_rq::sum_weight
- Rename cfs_rq::avg_vruntime to ::sum_w_vruntime & helper functions
- Introduce and use the vruntime_cmp() and vruntime_op() wrappers
for wrapped-signed aritmetics
- Sort out 'blocked_load*' namespace noise
(Ingo Molnar)
Scheduler debugging code updates:
- Export hidden tracepoints to modules (Gabriele Monaco)
- Convert copy_from_user() + kstrtouint() to kstrtouint_from_user()
(Fushuai Wang)
- Add assertions to QUEUE_CLASS (Peter Zijlstra)
- hrtimer: Fix tracing oddity (Thomas Gleixner)
Misc fixes and cleanups:
- Re-evaluate scheduling when migrating queued tasks out of
throttled cgroups (Zicheng Qu)
- Remove task_struct->faults_disabled_mapping (Christoph Hellwig)
- Fix math notation errors in avg_vruntime comment (Zhan Xusheng)
- sched/cpufreq: Use %pe format for PTR_ERR() printing (zenghongling)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
"Scheduler Kconfig space updates:
- Further consolidate configurable preemption modes (Peter Zijlstra)
Reduce the number of architectures that are allowed to offer
PREEMPT_NONE and PREEMPT_VOLUNTARY, reducing the number of
preemption models from four to just two: 'full' and 'lazy' on
up-to-date architectures (arm64, loongarch, powerpc, riscv, s390,
x86).
None and voluntary are only available as legacy features on
platforms that don't implement lazy preemption yet, or which don't
even support preemption.
The goal is to eventually remove cond_resched() and voluntary
preemption altogether.
RSEQ based 'scheduler time slice extension' support (Thomas Gleixner
and Peter Zijlstra):
This allows a thread to request a time slice extension when it enters
a critical section to avoid contention on a resource when the thread
is scheduled out inside of the critical section.
- Add fields and constants for time slice extension
- Provide static branch for time slice extensions
- Add statistics for time slice extensions
- Add prctl() to enable time slice extensions
- Implement sys_rseq_slice_yield()
- Implement syscall entry work for time slice extensions
- Implement time slice extension enforcement timer
- Reset slice extension when scheduled
- Implement rseq_grant_slice_extension()
- entry: Hook up rseq time slice extension
- selftests: Implement time slice extension test
- Allow registering RSEQ with slice extension
- Move slice_ext_nsec to debugfs
- Lower default slice extension
- selftests/rseq: Add rseq slice histogram script
Scheduler performance/scalability improvements:
- Update rq->avg_idle when a task is moved to an idle CPU, which
improves the scalability of various workloads (Shubhang Kaushik)
- Reorder fields in 'struct rq' for better caching (Blake Jones)
- Fair scheduler SMP NOHZ balancing code speedups (Shrikanth Hegde):
- Move checking for nohz cpus after time check
- Change likelyhood of nohz.nr_cpus
- Remove nohz.nr_cpus and use weight of cpumask instead
- Avoid false sharing for sched_clock_irqtime (Wangyang Guo)
- Cleanups (Yury Norov):
- Drop useless cpumask_empty() in find_energy_efficient_cpu()
- Simplify task_numa_find_cpu()
- Use cpumask_weight_and() in sched_balance_find_dst_group()
DL scheduler updates:
- Add a deadline server for sched_ext tasks (by Andrea Righi and Joel
Fernandes, with fixes by Peter Zijlstra)
RT scheduler updates:
- Skip currently executing CPU in rto_next_cpu() (Chen Jinghuang)
Entry code updates and performance improvements (Jinjie Ruan)
This is part of the scheduler tree in this cycle due to inter-
dependencies with the RSEQ based time slice extension work:
- Remove unused syscall argument from syscall_trace_enter()
- Rework syscall_exit_to_user_mode_work() for architecture reuse
- Add arch_ptrace_report_syscall_entry/exit()
- Inline syscall_exit_work() and syscall_trace_enter()
Scheduler core updates (Peter Zijlstra):
- Rework sched_class::wakeup_preempt() and rq_modified_*()
- Avoid rq->lock bouncing in sched_balance_newidle()
- Rename rcu_dereference_check_sched_domain() =>
rcu_dereference_sched_domain()
- <linux/compiler_types.h>: Add the __signed_scalar_typeof() helper
Fair scheduler updates/refactoring (Peter Zijlstra and Ingo Molnar):
- Fold the sched_avg update
- Change rcu_dereference_check_sched_domain() to rcu-sched
- Switch to rcu_dereference_all()
- Remove superfluous rcu_read_lock()
- Limit hrtick work
- Join two #ifdef CONFIG_FAIR_GROUP_SCHED blocks
- Clean up comments in 'struct cfs_rq'
- Separate se->vlag from se->vprot
- Rename cfs_rq::avg_load to cfs_rq::sum_weight
- Rename cfs_rq::avg_vruntime to ::sum_w_vruntime & helper functions
- Introduce and use the vruntime_cmp() and vruntime_op() wrappers for
wrapped-signed aritmetics
- Sort out 'blocked_load*' namespace noise
Scheduler debugging code updates:
- Export hidden tracepoints to modules (Gabriele Monaco)
- Convert copy_from_user() + kstrtouint() to kstrtouint_from_user()
(Fushuai Wang)
- Add assertions to QUEUE_CLASS (Peter Zijlstra)
- hrtimer: Fix tracing oddity (Thomas Gleixner)
Misc fixes and cleanups:
- Re-evaluate scheduling when migrating queued tasks out of throttled
cgroups (Zicheng Qu)
- Remove task_struct->faults_disabled_mapping (Christoph Hellwig)
- Fix math notation errors in avg_vruntime comment (Zhan Xusheng)
- sched/cpufreq: Use %pe format for PTR_ERR() printing
(zenghongling)"
* tag 'sched-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (64 commits)
sched: Re-evaluate scheduling when migrating queued tasks out of throttled cgroups
sched/cpufreq: Use %pe format for PTR_ERR() printing
sched/rt: Skip currently executing CPU in rto_next_cpu()
sched/clock: Avoid false sharing for sched_clock_irqtime
selftests/sched_ext: Add test for DL server total_bw consistency
selftests/sched_ext: Add test for sched_ext dl_server
sched/debug: Fix dl_server (re)start conditions
sched/debug: Add support to change sched_ext server params
sched_ext: Add a DL server for sched_ext tasks
sched/debug: Stop and start server based on if it was active
sched/debug: Fix updating of ppos on server write ops
sched/deadline: Clear the defer params
entry: Inline syscall_exit_work() and syscall_trace_enter()
entry: Add arch_ptrace_report_syscall_entry/exit()
entry: Rework syscall_exit_to_user_mode_work() for architecture reuse
entry: Remove unused syscall argument from syscall_trace_enter()
sched: remove task_struct->faults_disabled_mapping
sched: Update rq->avg_idle when a task is moved to an idle CPU
selftests/rseq: Add rseq slice histogram script
hrtimer: Fix trace oddity
...
x86 PMU driver updates:
- Add support for the core PMU for Intel Diamond Rapids (DMR) CPUs.
Compared to previous iterations of the Intel PMU code, there's
been a lot of changes, which center around three main areas:
- Introduce the OFF-MODULE RESPONSE (OMR) facility to
replace the Off-Core Response (OCR) facility
- New PEBS data source encoding layout
- Support the new "RDPMC user disable" feature
(Dapeng Mi)
- Likewise, a large series adds uncore PMU support for
Intel Diamond Rapids (DMR) CPUs, which center around these
four main areas:
- DMR may have two Integrated I/O and Memory Hub (IMH) dies,
separate from the compute tile (CBB) dies. Each CBB and
each IMH die has its own discovery domain.
- Unlike prior CPUs that retrieve the global discovery table
portal exclusively via PCI or MSR, DMR uses PCI for IMH PMON
discovery and MSR for CBB PMON discovery.
- DMR introduces several new PMON types: SCA, HAMVF, D2D_ULA,
UBR, PCIE4, CRS, CPC, ITC, OTC, CMS, and PCIE6.
- IIO free-running counters in DMR are MMIO-based, unlike SPR.
(Zide Chen)
- Also add support for Add missing PMON units for Intel Panther Lake,
and support Nova Lake (NVL), which largely maps to Panther Lake.
(Zide Chen)
- KVM integration: Add support for mediated vPMUs (by Kan Liang
and Sean Christopherson, with fixes and cleanups by Peter Zijlstra,
Sandipan Das and Mingwei Zhang)
- Add Intel cstate driver to support for Wildcat Lake (WCL)
CPUs, which are a low-power variant of Panther Lake.
(Zide Chen)
- Add core, cstate and MSR PMU support for the Airmont NP Intel CPU
(aka MaxLinear Lightning Mountain), which maps to the existing
Airmont code. (Martin Schiller)
Performance enhancements:
- core: Speed up kexec shutdown by avoiding unnecessary
cross CPU calls. (Jan H. Schönherr)
- core: Fix slow perf_event_task_exit() with LBR callstacks
(Namhyung Kim)
User-space stack unwinding support:
- Various cleanups and refactorings in preparation to generalize
the unwinding code for other architectures. (Jens Remus)
Uprobes updates:
- Transition from kmap_atomic to kmap_local_page (Keke Ming)
- Fix incorrect lockdep condition in filter_chain() (Breno Leitao)
- Fix XOL allocation failure for 32-bit tasks (Oleg Nesterov)
Misc fixes and cleanups:
- s390: Remove kvm_types.h from Kbuild (Randy Dunlap)
- x86/intel/uncore: Convert comma to semicolon (Chen Ni)
- x86/uncore: Clean up const mismatch (Greg Kroah-Hartman)
- x86/ibs: Fix typo in dc_l2tlb_miss comment (Xiang-Bin Shi)
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull performance event updates from Ingo Molnar:
"x86 PMU driver updates:
- Add support for the core PMU for Intel Diamond Rapids (DMR) CPUs
(Dapeng Mi)
Compared to previous iterations of the Intel PMU code, there's been
a lot of changes, which center around three main areas:
- Introduce the OFF-MODULE RESPONSE (OMR) facility to replace the
Off-Core Response (OCR) facility
- New PEBS data source encoding layout
- Support the new "RDPMC user disable" feature
- Likewise, a large series adds uncore PMU support for Intel Diamond
Rapids (DMR) CPUs (Zide Chen)
This centers around these four main areas:
- DMR may have two Integrated I/O and Memory Hub (IMH) dies,
separate from the compute tile (CBB) dies. Each CBB and each IMH
die has its own discovery domain.
- Unlike prior CPUs that retrieve the global discovery table
portal exclusively via PCI or MSR, DMR uses PCI for IMH PMON
discovery and MSR for CBB PMON discovery.
- DMR introduces several new PMON types: SCA, HAMVF, D2D_ULA, UBR,
PCIE4, CRS, CPC, ITC, OTC, CMS, and PCIE6.
- IIO free-running counters in DMR are MMIO-based, unlike SPR.
- Also add support for Add missing PMON units for Intel Panther Lake,
and support Nova Lake (NVL), which largely maps to Panther Lake.
(Zide Chen)
- KVM integration: Add support for mediated vPMUs (by Kan Liang and
Sean Christopherson, with fixes and cleanups by Peter Zijlstra,
Sandipan Das and Mingwei Zhang)
- Add Intel cstate driver to support for Wildcat Lake (WCL) CPUs,
which are a low-power variant of Panther Lake (Zide Chen)
- Add core, cstate and MSR PMU support for the Airmont NP Intel CPU
(aka MaxLinear Lightning Mountain), which maps to the existing
Airmont code (Martin Schiller)
Performance enhancements:
- Speed up kexec shutdown by avoiding unnecessary cross CPU calls
(Jan H. Schönherr)
- Fix slow perf_event_task_exit() with LBR callstacks (Namhyung Kim)
User-space stack unwinding support:
- Various cleanups and refactorings in preparation to generalize the
unwinding code for other architectures (Jens Remus)
Uprobes updates:
- Transition from kmap_atomic to kmap_local_page (Keke Ming)
- Fix incorrect lockdep condition in filter_chain() (Breno Leitao)
- Fix XOL allocation failure for 32-bit tasks (Oleg Nesterov)
Misc fixes and cleanups:
- s390: Remove kvm_types.h from Kbuild (Randy Dunlap)
- x86/intel/uncore: Convert comma to semicolon (Chen Ni)
- x86/uncore: Clean up const mismatch (Greg Kroah-Hartman)
- x86/ibs: Fix typo in dc_l2tlb_miss comment (Xiang-Bin Shi)"
* tag 'perf-core-2026-02-09' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (58 commits)
s390: remove kvm_types.h from Kbuild
uprobes: Fix incorrect lockdep condition in filter_chain()
x86/ibs: Fix typo in dc_l2tlb_miss comment
x86/uprobes: Fix XOL allocation failure for 32-bit tasks
perf/x86/intel/uncore: Convert comma to semicolon
perf/x86/intel: Add support for rdpmc user disable feature
perf/x86: Use macros to replace magic numbers in attr_rdpmc
perf/x86/intel: Add core PMU support for Novalake
perf/x86/intel: Add support for PEBS memory auxiliary info field in NVL
perf/x86/intel: Add core PMU support for DMR
perf/x86/intel: Add support for PEBS memory auxiliary info field in DMR
perf/x86/intel: Support the 4 new OMR MSRs introduced in DMR and NVL
perf/core: Fix slow perf_event_task_exit() with LBR callstacks
perf/core: Speed up kexec shutdown by avoiding unnecessary cross CPU calls
uprobes: use kmap_local_page() for temporary page mappings
arm/uprobes: use kmap_local_page() in arch_uprobe_copy_ixol()
mips/uprobes: use kmap_local_page() in arch_uprobe_copy_ixol()
arm64/uprobes: use kmap_local_page() in arch_uprobe_copy_ixol()
riscv/uprobes: use kmap_local_page() in arch_uprobe_copy_ixol()
perf/x86/intel/uncore: Add Nova Lake support
...
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Merge tag 'bpf-next-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Pull bpf updates from Alexei Starovoitov:
- Support associating BPF program with struct_ops (Amery Hung)
- Switch BPF local storage to rqspinlock and remove recursion detection
counters which were causing false positives (Amery Hung)
- Fix live registers marking for indirect jumps (Anton Protopopov)
- Introduce execution context detection BPF helpers (Changwoo Min)
- Improve verifier precision for 32bit sign extension pattern
(Cupertino Miranda)
- Optimize BTF type lookup by sorting vmlinux BTF and doing binary
search (Donglin Peng)
- Allow states pruning for misc/invalid slots in iterator loops (Eduard
Zingerman)
- In preparation for ASAN support in BPF arenas teach libbpf to move
global BPF variables to the end of the region and enable arena kfuncs
while holding locks (Emil Tsalapatis)
- Introduce support for implicit arguments in kfuncs and migrate a
number of them to new API. This is a prerequisite for cgroup
sub-schedulers in sched-ext (Ihor Solodrai)
- Fix incorrect copied_seq calculation in sockmap (Jiayuan Chen)
- Fix ORC stack unwind from kprobe_multi (Jiri Olsa)
- Speed up fentry attach by using single ftrace direct ops in BPF
trampolines (Jiri Olsa)
- Require frozen map for calculating map hash (KP Singh)
- Fix lock entry creation in TAS fallback in rqspinlock (Kumar
Kartikeya Dwivedi)
- Allow user space to select cpu in lookup/update operations on per-cpu
array and hash maps (Leon Hwang)
- Make kfuncs return trusted pointers by default (Matt Bobrowski)
- Introduce "fsession" support where single BPF program is executed
upon entry and exit from traced kernel function (Menglong Dong)
- Allow bpf_timer and bpf_wq use in all programs types (Mykyta
Yatsenko, Andrii Nakryiko, Kumar Kartikeya Dwivedi, Alexei
Starovoitov)
- Make KF_TRUSTED_ARGS the default for all kfuncs and clean up their
definition across the tree (Puranjay Mohan)
- Allow BPF arena calls from non-sleepable context (Puranjay Mohan)
- Improve register id comparison logic in the verifier and extend
linked registers with negative offsets (Puranjay Mohan)
- In preparation for BPF-OOM introduce kfuncs to access memcg events
(Roman Gushchin)
- Use CFI compatible destructor kfunc type (Sami Tolvanen)
- Add bitwise tracking for BPF_END in the verifier (Tianci Cao)
- Add range tracking for BPF_DIV and BPF_MOD in the verifier (Yazhou
Tang)
- Make BPF selftests work with 64k page size (Yonghong Song)
* tag 'bpf-next-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (268 commits)
selftests/bpf: Fix outdated test on storage->smap
selftests/bpf: Choose another percpu variable in bpf for btf_dump test
selftests/bpf: Remove test_task_storage_map_stress_lookup
selftests/bpf: Update task_local_storage/task_storage_nodeadlock test
selftests/bpf: Update task_local_storage/recursion test
selftests/bpf: Update sk_storage_omem_uncharge test
bpf: Switch to bpf_selem_unlink_nofail in bpf_local_storage_{map_free, destroy}
bpf: Support lockless unlink when freeing map or local storage
bpf: Prepare for bpf_selem_unlink_nofail()
bpf: Remove unused percpu counter from bpf_local_storage_map_free
bpf: Remove cgroup local storage percpu counter
bpf: Remove task local storage percpu counter
bpf: Change local_storage->lock and b->lock to rqspinlock
bpf: Convert bpf_selem_unlink to failable
bpf: Convert bpf_selem_link_map to failable
bpf: Convert bpf_selem_unlink_map to failable
bpf: Select bpf_local_storage_map_bucket based on bpf_local_storage
selftests/xsk: fix number of Tx frags in invalid packet
selftests/xsk: properly handle batch ending in the middle of a packet
bpf: Prevent reentrance into call_rcu_tasks_trace()
...
- Various missed __counted_by annotations (Thorsten Blum)
- Various missed -Wflex-array-member-not-at-end fixes (Gustavo A. R. Silva)
- Avoid leftover tempfiles for interrupted compile-time FORTIFY tests
(Nicolas Schier)
- Remove non-existant CONFIG_UBSAN_REPORT_FULL from docs (Stefan Wiehler)
- fortify: Use C arithmetic not FIELD_xxx() in FORTIFY_REASON defines
(David Laight)
- Add __counted_by_ptr attribute, tests, and first user (Bill Wendling,
Kees Cook)
- Update MAINTAINERS file to make hardening section not include pstore
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Merge tag 'hardening-v7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull hardening updates from Kees Cook:
"Mostly small cleanups and various scattered annotations and flex array
warning fixes that we reviewed by unlanded in other trees. Introduces
new annotation for expanding counted_by to pointer members, now that
compiler behavior between GCC and Clang has been normalized.
- Various missed __counted_by annotations (Thorsten Blum)
- Various missed -Wflex-array-member-not-at-end fixes (Gustavo A. R.
Silva)
- Avoid leftover tempfiles for interrupted compile-time FORTIFY tests
(Nicolas Schier)
- Remove non-existant CONFIG_UBSAN_REPORT_FULL from docs (Stefan
Wiehler)
- fortify: Use C arithmetic not FIELD_xxx() in FORTIFY_REASON defines
(David Laight)
- Add __counted_by_ptr attribute, tests, and first user (Bill
Wendling, Kees Cook)
- Update MAINTAINERS file to make hardening section not include
pstore"
* tag 'hardening-v7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
MAINTAINERS: pstore: Remove L: entry
nfp: tls: Avoid -Wflex-array-member-not-at-end warnings
carl9170: Avoid -Wflex-array-member-not-at-end warning
coredump: Use __counted_by_ptr for struct core_name::corename
lkdtm/bugs: Add __counted_by_ptr() test PTR_BOUNDS
compiler_types.h: Attributes: Add __counted_by_ptr macro
fortify: Cleanup temp file also on non-successful exit
fortify: Rename temporary file to match ignore pattern
fortify: Use C arithmetic not FIELD_xxx() in FORTIFY_REASON defines
ecryptfs: Annotate struct ecryptfs_message with __counted_by
fs/xattr: Annotate struct simple_xattr with __counted_by
crypto: af_alg - Annotate struct af_alg_iv with __counted_by
Kconfig.ubsan: Remove CONFIG_UBSAN_REPORT_FULL from documentation
drm/nouveau: fifo: Avoid -Wflex-array-member-not-at-end warning
affinity of unbound kthreads (node or custom cpumask) against
housekeeping (CPU isolation) constraints and CPU hotplug events.
One crucial missing piece is the handling of cpuset: when an isolated
partition is created, deleted, or its CPUs updated, all the unbound
kthreads in the top cpuset become indifferently affine to _all_ the
non-isolated CPUs, possibly breaking their preferred affinity along
the way.
Solve this with performing the kthreads affinity update from cpuset to
the kthreads consolidated relevant code instead so that preferred
affinities are honoured and applied against the updated cpuset isolated
partitions.
The dispatch of the new isolated cpumasks to timers, workqueues and
kthreads is performed by housekeeping, as per the nice Tejun's
suggestion.
As a welcome side effect, HK_TYPE_DOMAIN then integrates both the set
from boot defined domain isolation (through isolcpus=) and cpuset
isolated partitions. Housekeeping cpumasks are now modifiable with a
specific RCU based synchronization. A big step toward making nohz_full=
also mutable through cpuset in the future.
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Merge tag 'kthread-for-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks
Pull kthread updates from Frederic Weisbecker:
"The kthread code provides an infrastructure which manages the
preferred affinity of unbound kthreads (node or custom cpumask)
against housekeeping (CPU isolation) constraints and CPU hotplug
events.
One crucial missing piece is the handling of cpuset: when an isolated
partition is created, deleted, or its CPUs updated, all the unbound
kthreads in the top cpuset become indifferently affine to _all_ the
non-isolated CPUs, possibly breaking their preferred affinity along
the way.
Solve this with performing the kthreads affinity update from cpuset to
the kthreads consolidated relevant code instead so that preferred
affinities are honoured and applied against the updated cpuset
isolated partitions.
The dispatch of the new isolated cpumasks to timers, workqueues and
kthreads is performed by housekeeping, as per the nice Tejun's
suggestion.
As a welcome side effect, HK_TYPE_DOMAIN then integrates both the set
from boot defined domain isolation (through isolcpus=) and cpuset
isolated partitions. Housekeeping cpumasks are now modifiable with a
specific RCU based synchronization. A big step toward making
nohz_full= also mutable through cpuset in the future"
* tag 'kthread-for-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks: (33 commits)
doc: Add housekeeping documentation
kthread: Document kthread_affine_preferred()
kthread: Comment on the purpose and placement of kthread_affine_node() call
kthread: Honour kthreads preferred affinity after cpuset changes
sched/arm64: Move fallback task cpumask to HK_TYPE_DOMAIN
sched: Switch the fallback task allowed cpumask to HK_TYPE_DOMAIN
kthread: Rely on HK_TYPE_DOMAIN for preferred affinity management
kthread: Include kthreadd to the managed affinity list
kthread: Include unbound kthreads in the managed affinity list
kthread: Refine naming of affinity related fields
PCI: Remove superfluous HK_TYPE_WQ check
sched/isolation: Remove HK_TYPE_TICK test from cpu_is_isolated()
cpuset: Remove cpuset_cpu_is_isolated()
timers/migration: Remove superfluous cpuset isolation test
cpuset: Propagate cpuset isolation update to timers through housekeeping
cpuset: Propagate cpuset isolation update to workqueue through housekeeping
PCI: Flush PCI probe workqueue on cpuset isolated partition change
sched/isolation: Flush vmstat workqueues on cpuset isolated partition change
sched/isolation: Flush memcg workqueues on cpuset isolated partition change
cpuset: Update HK_TYPE_DOMAIN cpumask from cpuset
...
Please consider pulling these changes from the signed vfs-7.0-rc1.misc tag.
Thanks!
Christian
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Merge tag 'vfs-7.0-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull misc vfs updates from Christian Brauner:
"This contains a mix of VFS cleanups, performance improvements, API
fixes, documentation, and a deprecation notice.
Scalability and performance:
- Rework pid allocation to only take pidmap_lock once instead of
twice during alloc_pid(), improving thread creation/teardown
throughput by 10-16% depending on false-sharing luck. Pad the
namespace refcount to reduce false-sharing
- Track file lock presence via a flag in ->i_opflags instead of
reading ->i_flctx, avoiding false-sharing with ->i_readcount on
open/close hot paths. Measured 4-16% improvement on 24-core
open-in-a-loop benchmarks
- Use a consume fence in locks_inode_context() to match the
store-release/load-consume idiom, eliminating a hardware fence on
some architectures
- Annotate cdev_lock with __cacheline_aligned_in_smp to prevent
false-sharing
- Remove a redundant DCACHE_MANAGED_DENTRY check in
__follow_mount_rcu() that never fires since the caller already
verifies it, eliminating a 100% mispredicted branch
- Fix a 100% mispredicted likely() in devcgroup_inode_permission()
that became wrong after a prior code reorder
Bug fixes and correctness:
- Make insert_inode_locked() wait for inode destruction instead of
skipping, fixing a corner case where two matching inodes could
exist in the hash
- Move f_mode initialization before file_ref_init() in alloc_file()
to respect the SLAB_TYPESAFE_BY_RCU ordering contract
- Add a WARN_ON_ONCE guard in try_to_free_buffers() for folios with
no buffers attached, preventing a null pointer dereference when
AS_RELEASE_ALWAYS is set but no release_folio op exists
- Fix select restart_block to store end_time as timespec64, avoiding
truncation of tv_sec on 32-bit architectures
- Make dump_inode() use get_kernel_nofault() to safely access inode
and superblock fields, matching the dump_mapping() pattern
API modernization:
- Make posix_acl_to_xattr() allocate the buffer internally since
every single caller was doing it anyway. Reduces boilerplate and
unnecessary error checking across ~15 filesystems
- Replace deprecated simple_strtoul() with kstrtoul() for the
ihash_entries, dhash_entries, mhash_entries, and mphash_entries
boot parameters, adding proper error handling
- Convert chardev code to use guard(mutex) and __free(kfree) cleanup
patterns
- Replace min_t() with min() or umin() in VFS code to avoid silently
truncating unsigned long to unsigned int
- Gate LOOKUP_RCU assertions behind CONFIG_DEBUG_VFS since callers
already check the flag
Deprecation:
- Begin deprecating legacy BSD process accounting (acct(2)). The
interface has numerous footguns and better alternatives exist
(eBPF)
Documentation:
- Fix and complete kernel-doc for struct export_operations, removing
duplicated documentation between ReST and source
- Fix kernel-doc warnings for __start_dirop() and ilookup5_nowait()
Testing:
- Add a kunit test for initramfs cpio handling of entries with
filesize > PATH_MAX
Misc:
- Add missing <linux/init_task.h> include in fs_struct.c"
* tag 'vfs-7.0-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (28 commits)
posix_acl: make posix_acl_to_xattr() alloc the buffer
fs: make insert_inode_locked() wait for inode destruction
initramfs_test: kunit test for cpio.filesize > PATH_MAX
fs: improve dump_inode() to safely access inode fields
fs: add <linux/init_task.h> for 'init_fs'
docs: exportfs: Use source code struct documentation
fs: move initializing f_mode before file_ref_init()
exportfs: Complete kernel-doc for struct export_operations
exportfs: Mark struct export_operations functions at kernel-doc
exportfs: Fix kernel-doc output for get_name()
acct(2): begin the deprecation of legacy BSD process accounting
device_cgroup: remove branch hint after code refactor
VFS: fix __start_dirop() kernel-doc warnings
fs: Describe @isnew parameter in ilookup5_nowait()
fs/namei: Remove redundant DCACHE_MANAGED_DENTRY check in __follow_mount_rcu
fs: only assert on LOOKUP_RCU when built with CONFIG_DEBUG_VFS
select: store end_time as timespec64 in restart block
chardev: Switch to guard(mutex) and __free(kfree)
namespace: Replace simple_strtoul with kstrtoul to parse boot params
dcache: Replace simple_strtoul with kstrtoul in set_dhash_entries
...
Please consider pulling these changes from the signed vfs-7.0-rc1.nullfs tag.
Thanks!
Christian
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Merge tag 'vfs-7.0-rc1.nullfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs nullfs update from Christian Brauner:
"Add a completely catatonic minimal pseudo filesystem called "nullfs"
and make pivot_root() work in the initramfs.
Currently pivot_root() does not work on the real rootfs because it
cannot be unmounted. Userspace has to recursively delete initramfs
contents manually before continuing boot, using the fragile
switch_root sequence (overmount + chroot).
Add nullfs, a minimal immutable filesystem that serves as the true
root of the mount hierarchy. The mutable rootfs (tmpfs/ramfs) is
mounted on top of it. This allows userspace to simply:
chdir(new_root);
pivot_root(".", ".");
umount2(".", MNT_DETACH);
without the traditional switch_root workarounds. systemd already
handles this correctly. It tries pivot_root() first and falls back
to MS_MOVE only when that fails.
This also means rootfs mounts in unprivileged namespaces no longer
need MNT_LOCKED, since the immutable nullfs guarantees nothing can be
revealed by unmounting the covering mount.
nullfs is a single-instance filesystem (get_tree_single()) marked
SB_NOUSER | SB_I_NOEXEC | SB_I_NODEV with an immutable empty root
directory. This means sooner or later it can be used to overmount
other directories to hide their contents without any additional
protection needed.
We enable it unconditionally. If we see any real regression we'll
hide it behind a boot option.
nullfs has extensions beyond this in the future. It will serve as a
concept to support the creation of completely empty mount namespaces -
which is work coming up in the next cycle"
* tag 'vfs-7.0-rc1.nullfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs: use nullfs unconditionally as the real rootfs
docs: mention nullfs
fs: add immutable rootfs
fs: add init_pivot_root()
fs: ensure that internal tmpfs mount gets mount id zero
Please consider pulling these changes from the signed vfs-7.0-rc1.initrd tag.
Thanks!
Christian
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Merge tag 'vfs-7.0-rc1.initrd' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs initrd removal from Christian Brauner:
"Remove the deprecated linuxrc-based initrd code path and related dead
code. The linuxrc initrd path was deprecated in 2020 and this series
completes its removal. If we see real-life regressions we'll revert.
The core change removes handle_initrd() and init_linuxrc() — the
entire flow that ran /linuxrc from an initrd, pivoted roots, and
handed off to the real root filesystem. With that gone, initrd_load()
becomes void (no longer short-circuits prepare_namespace()),
rd_load_image() is simplified to always load /initrd.image instead of
taking a path, and rd_load_disk() is deleted.
The /proc/sys/kernel/real-root-dev sysctl and its backing variable are
removed since they only existed for linuxrc to communicate the real
root device back to the kernel.
The no-op load_ramdisk= and prompt_ramdisk= parameters are dropped,
and noinitrd and ramdisk_start= gain deprecation warnings.
Initramfs is entirely unaffected. The non-linuxrc initrd path
(root=/dev/ram0) is preserved but now carries a deprecation warning
targeting January 2027 removal"
* tag 'vfs-7.0-rc1.initrd' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
init: remove /proc/sys/kernel/real-root-dev
initrd: remove deprecated code path (linuxrc)
init: remove deprecated "load_ramdisk" and "prompt_ramdisk" command line parameters
Until now, cpuset would propagate isolated partition changes to
workqueues so that unbound workers get properly reaffined.
Since housekeeping now centralizes, synchronize and propagates isolation
cpumask changes, perform the work from that subsystem for consolidation
and consistency purposes.
For simplification purpose, the target function is adapted to take the
new housekeeping mask instead of the isolated mask.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: "Michal Koutný" <mkoutny@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Marco Crivellari <marco.crivellari@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Waiman Long <longman@redhat.com>
Cc: cgroups@vger.kernel.org
This reverts commit 2b69987be5 ("sched: Add
task_struct->faults_disabled_mapping"), which added this field without
review or maintainer signoff. With bcachefs removed from the
tree it is also unused now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260122085223.487092-1-hch@lst.de
Aside of a Kconfig knob add the following items:
- Two flag bits for the rseq user space ABI, which allow user space to
query the availability and enablement without a syscall.
- A new member to the user space ABI struct rseq, which is going to be
used to communicate request and grant between kernel and user space.
- A rseq state struct to hold the kernel state of this
- Documentation of the new mechanism
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251215155708.669472597@linutronix.de
Introduce __counted_by_ptr(), which works like __counted_by(), but for
pointer struct members.
struct foo {
int a, b, c;
char *buffer __counted_by_ptr(bytes);
short nr_bars;
struct bar *bars __counted_by_ptr(nr_bars);
size_t bytes;
};
Because "counted_by" can only be applied to pointer members in very
recent compiler versions, its application ends up needing to be distinct
from flexibe array "counted_by" annotations, hence a separate macro.
This is a reworking of Kees' previous patch [1].
Link: https://lore.kernel.org/all/20251020220118.1226740-1-kees@kernel.org/ [1]
Co-developed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Bill Wendling <morbo@google.com>
Link: https://patch.msgid.link/20260116005838.2419118-1-morbo@google.com
Signed-off-by: Kees Cook <kees@kernel.org>
initramfs unpack skips over cpio entries where namesize > PATH_MAX,
instead of returning an error. Add coverage for this behaviour.
Signed-off-by: David Disseldorp <ddiss@suse.de>
Link: https://patch.msgid.link/20260114135051.4943-2-ddiss@suse.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
Remove the "nullfs_rootfs" boot parameter and simply always use nullfs.
The mutable rootfs will be mounted on top of it. Systems that don't use
pivot_root() to pivot away from the real rootfs will have an additional
mount stick around but that shouldn't be a problem at all. If it is
we'll rever this commit.
This also simplifies the boot process and removes the need for the
traditional switch_root workarounds.
Suggested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Remove linuxrc initrd code path, which was deprecated in 2020.
Initramfs and (non-initial) RAM disks (i. e. brd) still work.
Both built-in and bootloader-supplied initramfs still work.
Non-linuxrc initrd code path (i. e. using /dev/ram as final root
filesystem) still works, but I put deprecation message into it.
Also I deprecate command line parameters "noinitrd" and "ramdisk_start=".
Signed-off-by: Askar Safin <safinaskar@gmail.com>
Link: https://patch.msgid.link/20251119222407.3333257-3-safinaskar@gmail.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Currently pivot_root() doesn't work on the real rootfs because it
cannot be unmounted. Userspace has to do a recursive removal of the
initramfs contents manually before continuing the boot.
Really all we want from the real rootfs is to serve as the parent mount
for anything that is actually useful such as the tmpfs or ramfs for
initramfs unpacking or the rootfs itself. There's no need for the real
rootfs to actually be anything meaningful or useful. Add a immutable
rootfs called "nullfs" that can be selected via the "nullfs_rootfs"
kernel command line option.
The kernel will mount a tmpfs/ramfs on top of it, unpack the initramfs
and fire up userspace which mounts the rootfs and can then just do:
chdir(rootfs);
pivot_root(".", ".");
umount2(".", MNT_DETACH);
and be done with it. (Ofc, userspace can also choose to retain the
initramfs contents by using something like pivot_root(".", "/initramfs")
without unmounting it.)
Technically this also means that the rootfs mount in unprivileged
namespaces doesn't need to become MNT_LOCKED anymore as it's guaranteed
that the immutable rootfs remains permanently empty so there cannot be
anything revealed by unmounting the covering mount.
In the future this will also allow us to create completely empty mount
namespaces without risking to leak anything.
systemd already handles this all correctly as it tries to pivot_root()
first and falls back to MS_MOVE only when that fails.
This goes back to various discussion in previous years and a LPC 2024
presentation about this very topic.
Link: https://patch.msgid.link/20260112-work-immutable-rootfs-v2-3-88dd1c34a204@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Now that RCU Tasks Trace has been re-implemented in terms of SRCU-fast,
the ->trc_ipi_to_cpu, ->trc_blkd_cpu, ->trc_blkd_node, ->trc_holdout_list,
and ->trc_reader_special task_struct fields are no longer used.
In addition, the rcu_tasks_trace_qs(), rcu_tasks_trace_qs_blkd(),
exit_tasks_rcu_finish_trace(), and rcu_spawn_tasks_trace_kthread(),
show_rcu_tasks_trace_gp_kthread(), rcu_tasks_trace_get_gp_data(),
rcu_tasks_trace_torture_stats_print(), and get_rcu_tasks_trace_gp_kthread()
functions and all the other functions that they invoke are no longer used.
Also, the TRC_NEED_QS and TRC_NEED_QS_CHECKED CPP macros are no longer used.
Neither are the rcu_tasks_trace_lazy_ms and rcu_task_ipi_delay rcupdate
module parameters and the TASKS_TRACE_RCU_READ_MB Kconfig option.
This commit therefore removes all of them.
[ paulmck: Apply Alexei Starovoitov feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: bpf@vger.kernel.org
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
This patch implements kconfig re-sync when the pahole version changes
between builds, similar to how it happens for compiler version change
via CC_VERSION_TEXT.
Define PAHOLE_VERSION in the top-level Makefile and export it for
config builds. Set CONFIG_PAHOLE_VERSION default to the exported
variable.
Kconfig records the PAHOLE_VERSION value in
include/config/auto.conf.cmd [1].
The Makefile includes auto.conf.cmd, so if PAHOLE_VERSION changes
between builds, make detects a dependency change and triggers
syncconfig to update the kconfig [2].
For external module builds, add a warning message in the prepare
target, similar to the existing compiler version mismatch warning.
Note that if pahole is not installed or available, PAHOLE_VERSION is
set to 0 by pahole-version.sh, so the (un)installation of pahole is
treated as a version change.
See previous discussions for context [3].
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/kconfig/preprocess.c?h=v6.18#n91
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Makefile?h=v6.18#n815
[3] https://lore.kernel.org/bpf/8f946abf-dd88-4fac-8bb4-84fcd8d81cf0@oracle.com/
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Nicolas Schier <nsc@kernel.org>
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Link: https://lore.kernel.org/bpf/20251219181321.1283664-6-ihor.solodrai@linux.dev
Currently, exposing PMU capabilities to a KVM guest is done by emulating
guest PMCs via host perf events, i.e. by having KVM be "just" another user
of perf. As a result, the guest and host are effectively competing for
resources, and emulating guest accesses to vPMU resources requires
expensive actions (expensive relative to the native instruction). The
overhead and resource competition results in degraded guest performance
and ultimately very poor vPMU accuracy.
To address the issues with the perf-emulated vPMU, introduce a "mediated
vPMU", where the data plane (PMCs and enable/disable knobs) is exposed
directly to the guest, but the control plane (event selectors and access
to fixed counters) is managed by KVM (via MSR interceptions). To allow
host perf usage of the PMU to (partially) co-exist with KVM/guest usage
of the PMU, KVM and perf will coordinate to a world switch between host
perf context and guest vPMU context near VM-Enter/VM-Exit.
Add two exported APIs, perf_{create,release}_mediated_pmu(), to allow KVM
to create and release a mediated PMU instance (per VM). Because host perf
context will be deactivated while the guest is running, mediated PMU usage
will be mutually exclusive with perf analysis of the guest, i.e. perf
events that do NOT exclude the guest will not behave as expected.
To avoid silent failure of !exclude_guest perf events, disallow creating a
mediated PMU if there are active !exclude_guest events, and on the perf
side, disallowing creating new !exclude_guest perf events while there is
at least one active mediated PMU.
Exempt PMU resources that do not support mediated PMU usage, i.e. that are
outside the scope/view of KVM's vPMU and will not be swapped out while the
guest is running.
Guard mediated PMU with a new kconfig to help readers identify code paths
that are unique to mediated PMU support, and to allow for adding arch-
specific hooks without stubs. KVM x86 is expected to be the only KVM
architecture to support a mediated PMU in the near future (e.g. arm64 is
trending toward a partitioned PMU implementation), and KVM x86 will select
PERF_GUEST_MEDIATED_PMU unconditionally, i.e. won't need stubs.
Immediately select PERF_GUEST_MEDIATED_PMU when KVM x86 is enabled so that
all paths are compile tested. Full KVM support is on its way...
[sean: add kconfig and WARNing, rewrite changelog, swizzle patch ordering]
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Xudong Hao <xudong.hao@intel.com>
Link: https://patch.msgid.link/20251206001720.468579-5-seanjc@google.com
...which do nothing. They were deprecated (in documentation) in
6b99e6e6aa ("Documentation/admin-guide: blockdev/ramdisk: remove use of
"rdev"") in 2020 and in kernel messages in c8376994c8 ("initrd: remove
support for multiple floppies") in 2020.
Signed-off-by: Askar Safin <safinaskar@gmail.com>
Link: https://patch.msgid.link/20251119222407.3333257-2-safinaskar@gmail.com
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
- The 6 patch series "panic: sys_info: Refactor and fix a potential
issue" from Andy Shevchenko fixes a build issue and does some cleanup in
ib/sys_info.c.
- The 9 patch series "Implement mul_u64_u64_div_u64_roundup()" from
David Laight enhances the 64-bit math code on behalf of a PWM driver and
beefs up the test module for these library functions.
- The 2 patch series "scripts/gdb/symbols: make BPF debug info available
to GDB" from Ilya Leoshkevich makes BPF symbol names, sizes, and line
numbers available to the GDB debugger.
- The 4 patch series "Enable hung_task and lockup cases to dump system
info on demand" from Feng Tang adds a sysctl which can be used to cause
additional info dumping when the hung-task and lockup detectors fire.
- The 6 patch series "lib/base64: add generic encoder/decoder, migrate
users" from Kuan-Wei Chiu adds a general base64 encoder/decoder to lib/
and migrates several users away from their private implementations.
- The 2 patch series "rbree: inline rb_first() and rb_last()" from Eric
Dumazet makes TCP a little faster.
- The 9 patch series "liveupdate: Rework KHO for in-kernel users" from
Pasha Tatashin reworks the KEXEC Handover interfaces in preparation for
Live Update Orchestrator (LUO), and possibly for other future clients.
- The 13 patch series "kho: simplify state machine and enable dynamic
updates" from Pasha Tatashin increases the flexibility of KEXEC
Handover. Also preparation for LUO.
- The 18 patch series "Live Update Orchestrator" from Pasha Tatashin is
a major new feature targeted at cloud environments. Quoting the [0/N]:
This series introduces the Live Update Orchestrator, a kernel subsystem
designed to facilitate live kernel updates using a kexec-based reboot.
This capability is critical for cloud environments, allowing hypervisors
to be updated with minimal downtime for running virtual machines. LUO
achieves this by preserving the state of selected resources, such as
memory, devices and their dependencies, across the kernel transition.
As a key feature, this series includes support for preserving memfd file
descriptors, which allows critical in-memory data, such as guest RAM or
any other large memory region, to be maintained in RAM across the kexec
reboot.
Mike Rappaport merits a mention here, for his extensive review and
testing work.
- The 3 patch series "kexec: reorganize kexec and kdump sysfs" from
Sourabh Jain moves the kexec and kdump sysfs entries from /sys/kernel/
to /sys/kernel/kexec/ and adds back-compatibility symlinks which can
hopefully be removed one day.
- The 2 patch series "kho: fixes for vmalloc restoration" from Mike
Rapoport fixes a BUG which was being hit during KHO restoration of
vmalloc() regions.
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Merge tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- "panic: sys_info: Refactor and fix a potential issue" (Andy Shevchenko)
fixes a build issue and does some cleanup in ib/sys_info.c
- "Implement mul_u64_u64_div_u64_roundup()" (David Laight)
enhances the 64-bit math code on behalf of a PWM driver and beefs up
the test module for these library functions
- "scripts/gdb/symbols: make BPF debug info available to GDB" (Ilya Leoshkevich)
makes BPF symbol names, sizes, and line numbers available to the GDB
debugger
- "Enable hung_task and lockup cases to dump system info on demand" (Feng Tang)
adds a sysctl which can be used to cause additional info dumping when
the hung-task and lockup detectors fire
- "lib/base64: add generic encoder/decoder, migrate users" (Kuan-Wei Chiu)
adds a general base64 encoder/decoder to lib/ and migrates several
users away from their private implementations
- "rbree: inline rb_first() and rb_last()" (Eric Dumazet)
makes TCP a little faster
- "liveupdate: Rework KHO for in-kernel users" (Pasha Tatashin)
reworks the KEXEC Handover interfaces in preparation for Live Update
Orchestrator (LUO), and possibly for other future clients
- "kho: simplify state machine and enable dynamic updates" (Pasha Tatashin)
increases the flexibility of KEXEC Handover. Also preparation for LUO
- "Live Update Orchestrator" (Pasha Tatashin)
is a major new feature targeted at cloud environments. Quoting the
cover letter:
This series introduces the Live Update Orchestrator, a kernel
subsystem designed to facilitate live kernel updates using a
kexec-based reboot. This capability is critical for cloud
environments, allowing hypervisors to be updated with minimal
downtime for running virtual machines. LUO achieves this by
preserving the state of selected resources, such as memory,
devices and their dependencies, across the kernel transition.
As a key feature, this series includes support for preserving
memfd file descriptors, which allows critical in-memory data, such
as guest RAM or any other large memory region, to be maintained in
RAM across the kexec reboot.
Mike Rappaport merits a mention here, for his extensive review and
testing work.
- "kexec: reorganize kexec and kdump sysfs" (Sourabh Jain)
moves the kexec and kdump sysfs entries from /sys/kernel/ to
/sys/kernel/kexec/ and adds back-compatibility symlinks which can
hopefully be removed one day
- "kho: fixes for vmalloc restoration" (Mike Rapoport)
fixes a BUG which was being hit during KHO restoration of vmalloc()
regions
* tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (139 commits)
calibrate: update header inclusion
Reinstate "resource: avoid unnecessary lookups in find_next_iomem_res()"
vmcoreinfo: track and log recoverable hardware errors
kho: fix restoring of contiguous ranges of order-0 pages
kho: kho_restore_vmalloc: fix initialization of pages array
MAINTAINERS: TPM DEVICE DRIVER: update the W-tag
init: replace simple_strtoul with kstrtoul to improve lpj_setup
KHO: fix boot failure due to kmemleak access to non-PRESENT pages
Documentation/ABI: new kexec and kdump sysfs interface
Documentation/ABI: mark old kexec sysfs deprecated
kexec: move sysfs entries to /sys/kernel/kexec
test_kho: always print restore status
kho: free chunks using free_page() instead of kfree()
selftests/liveupdate: add kexec test for multiple and empty sessions
selftests/liveupdate: add simple kexec-based selftest for LUO
selftests/liveupdate: add userspace API selftests
docs: add documentation for memfd preservation via LUO
mm: memfd_luo: allow preserving memfd
liveupdate: luo_file: add private argument to store runtime state
mm: shmem: export some functions to internal.h
...
dentries of created objects in dcache (and undo it when removing those).
Reference is grabbed and not released, but it's not actually _stored_
anywhere. That works, but it's hard to follow and verify; among other
things, we have no way to tell _which_ of the increments is intended
to be an unpaired one. Worse, on removal we need to decide whether
the reference had already been dropped, which can be non-trivial if
that removal is on umount and we need to figure out if this dentry is
pinned due to e.g. unlink() not done. Usually that is handled by using
kill_litter_super() as ->kill_sb(), but there are open-coded special
cases of the same (consider e.g. /proc/self).
Things get simpler if we introduce a new dentry flag (DCACHE_PERSISTENT)
marking those "leaked" dentries. Having it set claims responsibility
for +1 in refcount.
The end result this series is aiming for:
* get these unbalanced dget() and dput() replaced with new primitives that
would, in addition to adjusting refcount, set and clear persistency flag.
* instead of having kill_litter_super() mess with removing the remaining
"leaked" references (e.g. for all tmpfs files that hadn't been removed
prior to umount), have the regular shrink_dcache_for_umount() strip
DCACHE_PERSISTENT of all dentries, dropping the corresponding
reference if it had been set. After that kill_litter_super() becomes
an equivalent of kill_anon_super().
Doing that in a single step is not feasible - it would affect too many places
in too many filesystems. It has to be split into a series.
This work has really started early in 2024; quite a few preliminary pieces
have already gone into mainline. This chunk is finally getting to the
meat of that stuff - infrastructure and most of the conversions to it.
Some pieces are still sitting in the local branches, but the bulk of
that stuff is here.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'pull-persistency' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull persistent dentry infrastructure and conversion from Al Viro:
"Some filesystems use a kinda-sorta controlled dentry refcount leak to
pin dentries of created objects in dcache (and undo it when removing
those). A reference is grabbed and not released, but it's not actually
_stored_ anywhere.
That works, but it's hard to follow and verify; among other things, we
have no way to tell _which_ of the increments is intended to be an
unpaired one. Worse, on removal we need to decide whether the
reference had already been dropped, which can be non-trivial if that
removal is on umount and we need to figure out if this dentry is
pinned due to e.g. unlink() not done. Usually that is handled by using
kill_litter_super() as ->kill_sb(), but there are open-coded special
cases of the same (consider e.g. /proc/self).
Things get simpler if we introduce a new dentry flag
(DCACHE_PERSISTENT) marking those "leaked" dentries. Having it set
claims responsibility for +1 in refcount.
The end result this series is aiming for:
- get these unbalanced dget() and dput() replaced with new primitives
that would, in addition to adjusting refcount, set and clear
persistency flag.
- instead of having kill_litter_super() mess with removing the
remaining "leaked" references (e.g. for all tmpfs files that hadn't
been removed prior to umount), have the regular
shrink_dcache_for_umount() strip DCACHE_PERSISTENT of all dentries,
dropping the corresponding reference if it had been set. After that
kill_litter_super() becomes an equivalent of kill_anon_super().
Doing that in a single step is not feasible - it would affect too many
places in too many filesystems. It has to be split into a series.
This work has really started early in 2024; quite a few preliminary
pieces have already gone into mainline. This chunk is finally getting
to the meat of that stuff - infrastructure and most of the conversions
to it.
Some pieces are still sitting in the local branches, but the bulk of
that stuff is here"
* tag 'pull-persistency' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits)
d_make_discardable(): warn if given a non-persistent dentry
kill securityfs_recursive_remove()
convert securityfs
get rid of kill_litter_super()
convert rust_binderfs
convert nfsctl
convert rpc_pipefs
convert hypfs
hypfs: swich hypfs_create_u64() to returning int
hypfs: switch hypfs_create_str() to returning int
hypfs: don't pin dentries twice
convert gadgetfs
gadgetfs: switch to simple_remove_by_name()
convert functionfs
functionfs: switch to simple_remove_by_name()
functionfs: fix the open/removal races
functionfs: need to cancel ->reset_work in ->kill_sb()
functionfs: don't bother with ffs->ref in ffs_data_{opened,closed}()
functionfs: don't abuse ffs_data_closed() on fs shutdown
convert selinuxfs
...
new driver:
- Arm Ethos-U65/U85 accel driver
core:
- support the drm color pipeline in vkms/amdgfx
- add support for drm colorop pipeline
- add COLOR PIPELINE plane property
- add DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE
- throttle dirty worker with vblank
- use drm_for_each_bridge_in_chain_scoped in drm's bridge code
- Ensure drm_client_modeset tests are enabled in UML
- add simulated vblank interrupt - use in drivers
- dumb buffer sizing helper
- move freeing of drm client memory to driver
- crtc sharpness strength property
- stop using system_wq in scheduler/drivers
- support emergency restore in drm-client
rust:
- make slice::as_flattened usable on all supported rustc
- add FromBytes::from_bytes_prefix() method
- remove redundant device ptr from Rust GEM object
- Change how AlwaysRefCounted is implemented for GEM objects
gpuvm:
- Add deferred vm_bo cleanup to GPUVM (for rust)
atomic:
- cleanup and improve state handling interfaces
buddy:
- optimize block management
dma-buf:
- heaps: Create heap per CMA reserved location
- improve userspace documentation
dp:
- add POST_LT_ADJ_REQ training sequence
- DPCD dSC quirk for synaptics panamera devices
- helpers to query branch DSC max throughput
ttm:
- Rename ttm_bo_put to ttm_bo_fini
- allow page protection flags on risc-v
- rework pipelined eviction fence handling
amdgpu:
- enable amdgpu by default for SI/CI dGPUs
- enable DC by default on SI
- refactor CIK/SI enablement
- add ABM KMS property
- Re-enable DM idle optimizations
- DC Analog encoders support
- Powerplay fixes for fiji/iceland
- Enable DC on bonaire by default
- HMM cleanup
- Add new RAS framework
- DML2.1 updates
- YCbCr420 fixes
- DC FP fixes
- DMUB fixes
- LTTPR fixes
- DTBCLK fixes
- DMU cursor offload handling
- Userq validation improvements
- Unify shutdown callback handling
- Suspend improvements
- Power limit code cleanup
- SR-IOV fixes
- AUX backlight fixes
- DCN 3.5 fixes
- HDMI compliance fixes
- DCN 4.0.1 cursor updates
- DCN interrupt fix
- DC KMS full update improvements
- Add additional HDCP traces
- DCN 3.2 fixes
- DP MST fixes
- Add support for new SR-IOV mailbox interface
- UQ reset support
- HDP flush rework
- VCE1 support
amdkfd:
- HMM cleanups
- Relax checks on save area overallocations
- Fix GPU mappings after prefetch
radeon:
- refactor CIK/SI enablement.
xe:
- Initial Xe3P support
- panic support on VRAM for display
- fix stolen size check
- Loosen used tracking restriction
- New SR-IOV debugfs structure and debugfs updates
- Hide the GPU madvise flag behind a VM_BIND flag
- Always expose VRAM provisioning data on discrete GPUs
- Allow VRAM mappings for userptr when used with SVM
- Allow pinning of p2p dma-buf
- Use per-tile debugfs where appropriate
- Add documentation for Execution Queues
- PF improvements
- VF migration recovery redesign work
- User / Kernel VRAM partitioning
- Update Tile-based messages
- Allow configfs to disable specific GT types
- VF provisioning and migration improvements
- use SVM range helpers in PT layer
- Initial CRI support
- access VF registers using dedicated MMIO view
- limit number of jobs per exec queue
- add sriov_admin sysfs tree
- more crescent island specific support
- debugfs residency counter
- SRIOV migration work
- runtime registers for GFX 35
i915:
- add initial Xe3p_LPD display version 35 support
- Enable LNL+ content adaptive sharpness filter
- Use optimized VRR guardband
- Enable Xe3p LT PHY
- enable FBC support for Xe3p_LPD display
- add display 30.02 firmware support
- refactor SKL+ watermark latency setup
- refactor fbdev handling
- call i915/xe runtime PM via function pointers
- refactor i915/xe stolen memory/display interfaces
- use display version instead of gfx version in display code
- extend i915_display_info with Type-C port details
- lots of display cleanups/refactorings
- set O_LARGEFILE in __create_shmem
- skuip guc communication warning on reset
- fix time conversions
- defeature DRRS on LNL+
- refactor intel_frontbuffer split between i915/xe/display
- convert inteL_rom interfaces to struct drm_device
- unify display register polling interfaces
- aovid lock inversion when pinning to GGTT on CHV/BXT+VTD
panel:
- Add KD116N3730A08/A12, chromebook mt8189
- JT101TM023, LQ079L1SX01,
- GLD070WX3-SL01 MIPI DSI
- Samsung LTL106AL0, Samsung LTL106AL01
- Raystar RFF500F-AWH-DNN
- Winstar WF70A8SYJHLNGA,
- Wanchanglong w552946aaa
- Samsung SOFEF00
- Lenovo X13s panel.
- ilitek-ili9881c : add rpi 5" support
- visionx-rm69299 - add backlight support
- edp - support AUI B116XAN02.0
bridge:
- improve ref counting
- ti-sn65dsi86 - add support for DP mode with HPD
- synopsis: support CEC, init timer with correct freq
- ASL CS5263 DP-to-HDMI bridge support
nova-core:
- introduce bitfield! macro
- introduce safe integer converters
- GSP inits to fully booted state on Ampere
- Use more future-proof register for GPU identification
nova-drm:
- select NOVA_CORE
- 64-bit only
nouveau:
- improve reclocking on tegra 186+
- add large page and compression support
msm:
- GPU:
- Gen8 support: A840 (Kaanapali) and X2-85 (Glymur)
- A612 support
- MDSS:
- Added support for Glymur and QCS8300 platforms
- DPU:
- Enabled Quad-Pipe support, unlocking higher resolutions support
- Added support for Glymur platform
- Documented DPU on QCS8300 platform as supported
- DisplayPort:
- Added support for Glymur platform
- Added support lame remapping inside DP block
- Documented DisplayPort controller on QCS8300 and SM6150/QCS615 as
supported
tegra:
- NVJPG driver
panfrost:
- display JM contexts over debugfs
- export JM contexts to userspace
- improve error and job handling
panthor:
- support custom ASN_HASH for mt8196
- support mali-G1 GPU
- flush shmem write before mapping buffers uncached
- make timeout per-queue instead of per-job
mediatek:
- MT8195/88 HDMIv2/DDCv2 support
rockchip:
- dsi: add support for RK3368
amdxdna:
- enhance runtime PM
- last hardware error reading uapi
- support firmware debug output
- add resource and telemetry data uapi
- preemption support
imx:
- add driver for HDMI TX Parallel audio interface
ivpu:
- add support for user-managed preemption buffer
- add userptr support
- update JSM firware API to 3.33.0
- add better alloc/free warnings
- fix page fault in unbind all bos
- rework bind/unbind of imported buffers
- enable MCA ECC signalling
- split fw runtime and global memory buffers
- add fdinfo memory statistics
tidss:
- convert to drm logging
- logging cleanup
ast:
- refactor generation init paths
- add per chip generation detect_tx_chip
- set quirks for each chip model
atmel-hlcdc:
- set LCDC_ATTRE register in plane disable
- set correct values for plane scaler
solomon:
- use drm helper for get_modes and move_valid
sitronix:
- fix output position when clearing screens
qaic:
- support dma-buf exports
- support new firmware's READ_DATA implementation
- sahara AIC200 image table update
- add sysfs support
- add coredump support
- add uevents support
- PM support
sun4i:
- layer refactors to decouple plane from output
- improve DE33 support
vc4:
- switch to generic CEC helpers
komeda:
- use drm_ logging functions
vkms:
- configfs support for display configuration
vgem:
- fix fence timer deadlock
etnaviv:
- add HWDB entry for GC8000 Nano Ultra VIP r6205
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Merge tag 'drm-next-2025-12-03' of https://gitlab.freedesktop.org/drm/kernel
Pull drm updates from Dave Airlie:
"There was a rather late merge of a new color pipeline feature, that
some userspace projects are blocked on, and has seen a lot of work in
amdgpu. This should have seen some time in -next. There is additional
support for this for Intel, that if it arrives in the next day or two
I'll pass it on in another pull request and you can decide if you want
to take it.
Highlights:
- Arm Ethos NPU accelerator driver
- new DRM color pipeline support
- amdgpu will now run discrete SI/CIK cards instead of radeon, which
enables vulkan support in userspace
- msm gets gen8 gpu support
- initial Xe3P support in xe
Full detail summary:
New driver:
- Arm Ethos-U65/U85 accel driver
Core:
- support the drm color pipeline in vkms/amdgfx
- add support for drm colorop pipeline
- add COLOR PIPELINE plane property
- add DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE
- throttle dirty worker with vblank
- use drm_for_each_bridge_in_chain_scoped in drm's bridge code
- Ensure drm_client_modeset tests are enabled in UML
- add simulated vblank interrupt - use in drivers
- dumb buffer sizing helper
- move freeing of drm client memory to driver
- crtc sharpness strength property
- stop using system_wq in scheduler/drivers
- support emergency restore in drm-client
Rust:
- make slice::as_flattened usable on all supported rustc
- add FromBytes::from_bytes_prefix() method
- remove redundant device ptr from Rust GEM object
- Change how AlwaysRefCounted is implemented for GEM objects
gpuvm:
- Add deferred vm_bo cleanup to GPUVM (for rust)
atomic:
- cleanup and improve state handling interfaces
buddy:
- optimize block management
dma-buf:
- heaps: Create heap per CMA reserved location
- improve userspace documentation
dp:
- add POST_LT_ADJ_REQ training sequence
- DPCD dSC quirk for synaptics panamera devices
- helpers to query branch DSC max throughput
ttm:
- Rename ttm_bo_put to ttm_bo_fini
- allow page protection flags on risc-v
- rework pipelined eviction fence handling
amdgpu:
- enable amdgpu by default for SI/CI dGPUs
- enable DC by default on SI
- refactor CIK/SI enablement
- add ABM KMS property
- Re-enable DM idle optimizations
- DC Analog encoders support
- Powerplay fixes for fiji/iceland
- Enable DC on bonaire by default
- HMM cleanup
- Add new RAS framework
- DML2.1 updates
- YCbCr420 fixes
- DC FP fixes
- DMUB fixes
- LTTPR fixes
- DTBCLK fixes
- DMU cursor offload handling
- Userq validation improvements
- Unify shutdown callback handling
- Suspend improvements
- Power limit code cleanup
- SR-IOV fixes
- AUX backlight fixes
- DCN 3.5 fixes
- HDMI compliance fixes
- DCN 4.0.1 cursor updates
- DCN interrupt fix
- DC KMS full update improvements
- Add additional HDCP traces
- DCN 3.2 fixes
- DP MST fixes
- Add support for new SR-IOV mailbox interface
- UQ reset support
- HDP flush rework
- VCE1 support
amdkfd:
- HMM cleanups
- Relax checks on save area overallocations
- Fix GPU mappings after prefetch
radeon:
- refactor CIK/SI enablement
xe:
- Initial Xe3P support
- panic support on VRAM for display
- fix stolen size check
- Loosen used tracking restriction
- New SR-IOV debugfs structure and debugfs updates
- Hide the GPU madvise flag behind a VM_BIND flag
- Always expose VRAM provisioning data on discrete GPUs
- Allow VRAM mappings for userptr when used with SVM
- Allow pinning of p2p dma-buf
- Use per-tile debugfs where appropriate
- Add documentation for Execution Queues
- PF improvements
- VF migration recovery redesign work
- User / Kernel VRAM partitioning
- Update Tile-based messages
- Allow configfs to disable specific GT types
- VF provisioning and migration improvements
- use SVM range helpers in PT layer
- Initial CRI support
- access VF registers using dedicated MMIO view
- limit number of jobs per exec queue
- add sriov_admin sysfs tree
- more crescent island specific support
- debugfs residency counter
- SRIOV migration work
- runtime registers for GFX 35
i915:
- add initial Xe3p_LPD display version 35 support
- Enable LNL+ content adaptive sharpness filter
- Use optimized VRR guardband
- Enable Xe3p LT PHY
- enable FBC support for Xe3p_LPD display
- add display 30.02 firmware support
- refactor SKL+ watermark latency setup
- refactor fbdev handling
- call i915/xe runtime PM via function pointers
- refactor i915/xe stolen memory/display interfaces
- use display version instead of gfx version in display code
- extend i915_display_info with Type-C port details
- lots of display cleanups/refactorings
- set O_LARGEFILE in __create_shmem
- skuip guc communication warning on reset
- fix time conversions
- defeature DRRS on LNL+
- refactor intel_frontbuffer split between i915/xe/display
- convert inteL_rom interfaces to struct drm_device
- unify display register polling interfaces
- aovid lock inversion when pinning to GGTT on CHV/BXT+VTD
panel:
- Add KD116N3730A08/A12, chromebook mt8189
- JT101TM023, LQ079L1SX01,
- GLD070WX3-SL01 MIPI DSI
- Samsung LTL106AL0, Samsung LTL106AL01
- Raystar RFF500F-AWH-DNN
- Winstar WF70A8SYJHLNGA
- Wanchanglong w552946aaa
- Samsung SOFEF00
- Lenovo X13s panel
- ilitek-ili9881c - add rpi 5" support
- visionx-rm69299 - add backlight support
- edp - support AUI B116XAN02.0
bridge:
- improve ref counting
- ti-sn65dsi86 - add support for DP mode with HPD
- synopsis: support CEC, init timer with correct freq
- ASL CS5263 DP-to-HDMI bridge support
nova-core:
- introduce bitfield! macro
- introduce safe integer converters
- GSP inits to fully booted state on Ampere
- Use more future-proof register for GPU identification
nova-drm:
- select NOVA_CORE
- 64-bit only
nouveau:
- improve reclocking on tegra 186+
- add large page and compression support
msm:
- GPU:
- Gen8 support: A840 (Kaanapali) and X2-85 (Glymur)
- A612 support
- MDSS:
- Added support for Glymur and QCS8300 platforms
- DPU:
- Enabled Quad-Pipe support, unlocking higher resolutions support
- Added support for Glymur platform
- Documented DPU on QCS8300 platform as supported
- DisplayPort:
- Added support for Glymur platform
- Added support lame remapping inside DP block
- Documented DisplayPort controller on QCS8300 and SM6150/QCS615
as supported
tegra:
- NVJPG driver
panfrost:
- display JM contexts over debugfs
- export JM contexts to userspace
- improve error and job handling
panthor:
- support custom ASN_HASH for mt8196
- support mali-G1 GPU
- flush shmem write before mapping buffers uncached
- make timeout per-queue instead of per-job
mediatek:
- MT8195/88 HDMIv2/DDCv2 support
rockchip:
- dsi: add support for RK3368
amdxdna:
- enhance runtime PM
- last hardware error reading uapi
- support firmware debug output
- add resource and telemetry data uapi
- preemption support
imx:
- add driver for HDMI TX Parallel audio interface
ivpu:
- add support for user-managed preemption buffer
- add userptr support
- update JSM firware API to 3.33.0
- add better alloc/free warnings
- fix page fault in unbind all bos
- rework bind/unbind of imported buffers
- enable MCA ECC signalling
- split fw runtime and global memory buffers
- add fdinfo memory statistics
tidss:
- convert to drm logging
- logging cleanup
ast:
- refactor generation init paths
- add per chip generation detect_tx_chip
- set quirks for each chip model
atmel-hlcdc:
- set LCDC_ATTRE register in plane disable
- set correct values for plane scaler
solomon:
- use drm helper for get_modes and move_valid
sitronix:
- fix output position when clearing screens
qaic:
- support dma-buf exports
- support new firmware's READ_DATA implementation
- sahara AIC200 image table update
- add sysfs support
- add coredump support
- add uevents support
- PM support
sun4i:
- layer refactors to decouple plane from output
- improve DE33 support
vc4:
- switch to generic CEC helpers
komeda:
- use drm_ logging functions
vkms:
- configfs support for display configuration
vgem:
- fix fence timer deadlock
etnaviv:
- add HWDB entry for GC8000 Nano Ultra VIP r6205"
* tag 'drm-next-2025-12-03' of https://gitlab.freedesktop.org/drm/kernel: (1869 commits)
Revert "drm/amd: Skip power ungate during suspend for VPE"
drm/amdgpu: use common defines for HUB faults
drm/amdgpu/gmc12: add amdgpu_vm_handle_fault() handling
drm/amdgpu/gmc11: add amdgpu_vm_handle_fault() handling
drm/amdgpu: use static ids for ACP platform devs
drm/amdgpu/sdma6: Update SDMA 6.0.3 FW version to include UMQ protected-fence fix
drm/amdgpu: Forward VMID reservation errors
drm/amdgpu/gmc8: Delegate VM faults to soft IRQ handler ring
drm/amdgpu/gmc7: Delegate VM faults to soft IRQ handler ring
drm/amdgpu/gmc6: Delegate VM faults to soft IRQ handler ring
drm/amdgpu/gmc6: Cache VM fault info
drm/amdgpu/gmc6: Don't print MC client as it's unknown
drm/amdgpu/cz_ih: Enable soft IRQ handler ring
drm/amdgpu/tonga_ih: Enable soft IRQ handler ring
drm/amdgpu/iceland_ih: Enable soft IRQ handler ring
drm/amdgpu/cik_ih: Enable soft IRQ handler ring
drm/amdgpu/si_ih: Enable soft IRQ handler ring
drm/amd/display: fix typo in display_mode_core_structs.h
drm/amd/display: fix Smart Power OLED not working after S4
drm/amd/display: Move RGB-type check for audio sync to DCE HW sequence
...
- Enable -fms-extensions, allowing anonymous use of tagged struct or
union in struct/union (tag kbuild-ms-extensions-6.19). An exemplary
conversion patch is added here, too (btrfs).
- Introduce architecture-specific CC_CAN_LINK and flags for userprogs
- Add new packaging target 'modules-cpio-pkg' for building a initramfs
cpio w/ kmods
- Handle included .c files in gen_compile_commands
- Minor kbuild changes:
- Use objtree for module signing key path, fixing oot kmod signing
- Improve documentation of KBUILD_BUILD_TIMESTAMP
- Reuse KBUILD_USERCFLAGS for UAPI, instead of defining twice
- Rename scripts/Makefile.extrawarn to Makefile.warn
- Drop obsolete types.h check from headers_check.pl
- Remove outdated config leak ignore entries
Signed-off-by: Nicolas Schier <nsc@kernel.org>
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Merge tag 'kbuild-6.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux
Pull Kbuild updates from Nicolas Schier:
- Enable -fms-extensions, allowing anonymous use of tagged struct or
union in struct/union (tag kbuild-ms-extensions-6.19). An exemplary
conversion patch is added here, too (btrfs).
[ Editor's note: the core of this actually came in early through a
shared branch and a few other trees - Linus ]
- Introduce architecture-specific CC_CAN_LINK and flags for userprogs
- Add new packaging target 'modules-cpio-pkg' for building a initramfs
cpio w/ kmods
- Handle included .c files in gen_compile_commands
- Minor kbuild changes:
- Use objtree for module signing key path, fixing oot kmod signing
- Improve documentation of KBUILD_BUILD_TIMESTAMP
- Reuse KBUILD_USERCFLAGS for UAPI, instead of defining twice
- Rename scripts/Makefile.extrawarn to Makefile.warn
- Drop obsolete types.h check from headers_check.pl
- Remove outdated config leak ignore entries
* tag 'kbuild-6.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux:
kbuild: add target to build a cpio containing modules
initramfs: add gen_init_cpio to hostprogs unconditionally
kbuild: allow architectures to override CC_CAN_LINK
init: deduplicate cc-can-link.sh invocations
kbuild: don't enable CC_CAN_LINK if the dummy program generates warnings
scripts: headers_install.sh: Remove two outdated config leak ignore entries
scripts/clang-tools: Handle included .c files in gen_compile_commands
kbuild: uapi: Drop types.h check from headers_check.pl
kbuild: Rename Makefile.extrawarn to Makefile.warn
MAINTAINERS, .mailmap: Update mail address for Nicolas Schier
kbuild: uapi: reuse KBUILD_USERCFLAGS
kbuild: doc: improve KBUILD_BUILD_TIMESTAMP documentation
kbuild: Use objtree for module signing key path
btrfs: send: make use of -fms-extensions for defining struct fs_path
The recent enablement of RSEQ in glibc resulted in regressions which are
caused by the related overhead. It turned out that the decision to invoke
the exit to user work was not really a decision. More or less each
context switch caused that. There is a long list of small issues which
sums up nicely and results in a 3-4% regression in I/O benchmarks.
The other detail which caused issues due to extra work in context switch
and task migration is the CID (memory context ID) management. It also
requires to use a task work to consolidate the CID space, which is
executed in the context of an arbitrary task and results in sporadic
uncontrolled exit latencies.
The rewrite addresses this by:
- Removing deprecated and long unsupported functionality
- Moving the related data into dedicated data structures which are
optimized for fast path processing.
- Caching values so actual decisions can be made
- Replacing the current implementation with a optimized inlined variant.
- Separating fast and slow path for architectures which use the generic
entry code, so that only fault and error handling goes into the
TIF_NOTIFY_RESUME handler.
- Rewriting the CID management so that it becomes mostly invisible in the
context switch path. That moves the work of switching modes into the
fork/exit path, which is a reasonable tradeoff. That work is only
required when a process creates more threads than the cpuset it is
allowed to run on or when enough threads exit after that. An artificial
thread pool benchmarks which triggers this did not degrade, it actually
improved significantly.
The main effect in migration heavy scenarios is that runqueue lock held
time and therefore contention goes down significantly.
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Merge tag 'core-rseq-2025-11-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull rseq updates from Thomas Gleixner:
"A large overhaul of the restartable sequences and CID management:
The recent enablement of RSEQ in glibc resulted in regressions which
are caused by the related overhead. It turned out that the decision to
invoke the exit to user work was not really a decision. More or less
each context switch caused that. There is a long list of small issues
which sums up nicely and results in a 3-4% regression in I/O
benchmarks.
The other detail which caused issues due to extra work in context
switch and task migration is the CID (memory context ID) management.
It also requires to use a task work to consolidate the CID space,
which is executed in the context of an arbitrary task and results in
sporadic uncontrolled exit latencies.
The rewrite addresses this by:
- Removing deprecated and long unsupported functionality
- Moving the related data into dedicated data structures which are
optimized for fast path processing.
- Caching values so actual decisions can be made
- Replacing the current implementation with a optimized inlined
variant.
- Separating fast and slow path for architectures which use the
generic entry code, so that only fault and error handling goes into
the TIF_NOTIFY_RESUME handler.
- Rewriting the CID management so that it becomes mostly invisible in
the context switch path. That moves the work of switching modes
into the fork/exit path, which is a reasonable tradeoff. That work
is only required when a process creates more threads than the
cpuset it is allowed to run on or when enough threads exit after
that. An artificial thread pool benchmarks which triggers this did
not degrade, it actually improved significantly.
The main effect in migration heavy scenarios is that runqueue lock
held time and therefore contention goes down significantly"
* tag 'core-rseq-2025-11-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits)
sched/mmcid: Switch over to the new mechanism
sched/mmcid: Implement deferred mode change
irqwork: Move data struct to a types header
sched/mmcid: Provide CID ownership mode fixup functions
sched/mmcid: Provide new scheduler CID mechanism
sched/mmcid: Introduce per task/CPU ownership infrastructure
sched/mmcid: Serialize sched_mm_cid_fork()/exit() with a mutex
sched/mmcid: Provide precomputed maximal value
sched/mmcid: Move initialization out of line
signal: Move MMCID exit out of sighand lock
sched/mmcid: Convert mm CID mask to a bitmap
cpumask: Cache num_possible_cpus()
sched/mmcid: Use cpumask_weighted_or()
cpumask: Introduce cpumask_weighted_or()
sched/mmcid: Prevent pointless work in mm_update_cpus_allowed()
sched/mmcid: Move scheduler code out of global header
sched: Fixup whitespace damage
sched/mmcid: Cacheline align MM CID storage
sched/mmcid: Use proper data structures
sched/mmcid: Revert the complex CID management
...
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Merge tag 'kernel-6.19-rc1.cred' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull cred guard updates from Christian Brauner:
"This contains substantial credential infrastructure improvements
adding guard-based credential management that simplifies code and
eliminates manual reference counting in many subsystems.
Features:
- Kernel Credential Guards
Add with_kernel_creds() and scoped_with_kernel_creds() guards that
allow using the kernel credentials without allocating and copying
them. This was requested by Linus after seeing repeated
prepare_kernel_creds() calls that duplicate the kernel credentials
only to drop them again later.
The new guards completely avoid the allocation and never expose the
temporary variable to hold the kernel credentials anywhere in
callers.
- Generic Credential Guards
Add scoped_with_creds() guards for the common override_creds() and
revert_creds() pattern. This builds on earlier work that made
override_creds()/revert_creds() completely reference count free.
- Prepare Credential Guards
Add prepare credential guards for the more complex pattern of
preparing a new set of credentials and overriding the current
credentials with them:
- prepare_creds()
- modify new creds
- override_creds()
- revert_creds()
- put_cred()
Cleanups:
- Make init_cred static since it should not be directly accessed
- Add kernel_cred() helper to properly access the kernel credentials
- Fix scoped_class() macro that was introduced two cycles ago
- coredump: split out do_coredump() from vfs_coredump() for cleaner
credential handling
- coredump: move revert_cred() before coredump_cleanup()
- coredump: mark struct mm_struct as const
- coredump: pass struct linux_binfmt as const
- sev-dev: use guard for path"
* tag 'kernel-6.19-rc1.cred' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (36 commits)
trace: use override credential guard
trace: use prepare credential guard
coredump: use override credential guard
coredump: use prepare credential guard
coredump: split out do_coredump() from vfs_coredump()
coredump: mark struct mm_struct as const
coredump: pass struct linux_binfmt as const
coredump: move revert_cred() before coredump_cleanup()
sev-dev: use override credential guards
sev-dev: use prepare credential guard
sev-dev: use guard for path
cred: add prepare credential guard
net/dns_resolver: use credential guards in dns_query()
cgroup: use credential guards in cgroup_attach_permissions()
act: use credential guards in acct_write_process()
smb: use credential guards in cifs_get_spnego_key()
nfs: use credential guards in nfs_idmap_get_key()
nfs: use credential guards in nfs_local_call_write()
nfs: use credential guards in nfs_local_call_read()
erofs: use credential guards
...
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Merge tag 'namespace-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull namespace updates from Christian Brauner:
"This contains substantial namespace infrastructure changes including a new
system call, active reference counting, and extensive header cleanups.
The branch depends on the shared kbuild branch for -fms-extensions support.
Features:
- listns() system call
Add a new listns() system call that allows userspace to iterate
through namespaces in the system. This provides a programmatic
interface to discover and inspect namespaces, addressing
longstanding limitations:
Currently, there is no direct way for userspace to enumerate
namespaces. Applications must resort to scanning /proc/*/ns/ across
all processes, which is:
- Inefficient - requires iterating over all processes
- Incomplete - misses namespaces not attached to any running
process but kept alive by file descriptors, bind mounts, or
parent references
- Permission-heavy - requires access to /proc for many processes
- No ordering or ownership information
- No filtering per namespace type
The listns() system call solves these problems:
ssize_t listns(const struct ns_id_req *req, u64 *ns_ids,
size_t nr_ns_ids, unsigned int flags);
struct ns_id_req {
__u32 size;
__u32 spare;
__u64 ns_id;
struct /* listns */ {
__u32 ns_type;
__u32 spare2;
__u64 user_ns_id;
};
};
Features include:
- Pagination support for large namespace sets
- Filtering by namespace type (MNT_NS, NET_NS, USER_NS, etc.)
- Filtering by owning user namespace
- Permission checks respecting namespace isolation
- Active Reference Counting
Introduce an active reference count that tracks namespace
visibility to userspace. A namespace is visible in the following
cases:
- The namespace is in use by a task
- The namespace is persisted through a VFS object (namespace file
descriptor or bind-mount)
- The namespace is a hierarchical type and is the parent of child
namespaces
The active reference count does not regulate lifetime (that's still
done by the normal reference count) - it only regulates visibility
to namespace file handles and listns().
This prevents resurrection of namespaces that are pinned only for
internal kernel reasons (e.g., user namespaces held by
file->f_cred, lazy TLB references on idle CPUs, etc.) which should
not be accessible via (1)-(3).
- Unified Namespace Tree
Introduce a unified tree structure for all namespaces with:
- Fixed IDs assigned to initial namespaces
- Lookup based solely on inode number
- Maintained list of owned namespaces per user namespace
- Simplified rbtree comparison helpers
Cleanups
- Header Reorganization:
- Move namespace types into separate header (ns_common_types.h)
- Decouple nstree from ns_common header
- Move nstree types into separate header
- Switch to new ns_tree_{node,root} structures with helper functions
- Use guards for ns_tree_lock
- Initial Namespace Reference Count Optimization
- Make all reference counts on initial namespaces a nop to avoid
pointless cacheline ping-pong for namespaces that can never go
away
- Drop custom reference count initialization for initial namespaces
- Add NS_COMMON_INIT() macro and use it for all namespaces
- pid: rely on common reference count behavior
- Miscellaneous Cleanups
- Rename exit_task_namespaces() to exit_nsproxy_namespaces()
- Rename is_initial_namespace() and make argument const
- Use boolean to indicate anonymous mount namespace
- Simplify owner list iteration in nstree
- nsfs: raise SB_I_NODEV, SB_I_NOEXEC, and DCACHE_DONTCACHE explicitly
- nsfs: use inode_just_drop()
- pidfs: raise DCACHE_DONTCACHE explicitly
- pidfs: simplify PIDFD_GET__NAMESPACE ioctls
- libfs: allow to specify s_d_flags
- cgroup: add cgroup namespace to tree after owner is set
- nsproxy: fix free_nsproxy() and simplify create_new_namespaces()
Fixes:
- setns(pidfd, ...) race condition
Fix a subtle race when using pidfds with setns(). When the target
task exits after prepare_nsset() but before commit_nsset(), the
namespace's active reference count might have been dropped. If
setns() then installs the namespaces, it would bump the active
reference count from zero without taking the required reference on
the owner namespace, leading to underflow when later decremented.
The fix resurrects the ownership chain if necessary - if the caller
succeeded in grabbing passive references, the setns() should
succeed even if the target task exits or gets reaped.
- Return EFAULT on put_user() error instead of success
- Make sure references are dropped outside of RCU lock (some
namespaces like mount namespace sleep when putting the last
reference)
- Don't skip active reference count initialization for network
namespace
- Add asserts for active refcount underflow
- Add asserts for initial namespace reference counts (both passive
and active)
- ipc: enable is_ns_init_id() assertions
- Fix kernel-doc comments for internal nstree functions
- Selftests
- 15 active reference count tests
- 9 listns() functionality tests
- 7 listns() permission tests
- 12 inactive namespace resurrection tests
- 3 threaded active reference count tests
- commit_creds() active reference tests
- Pagination and stress tests
- EFAULT handling test
- nsid tests fixes"
* tag 'namespace-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (103 commits)
pidfs: simplify PIDFD_GET_<type>_NAMESPACE ioctls
nstree: fix kernel-doc comments for internal functions
nsproxy: fix free_nsproxy() and simplify create_new_namespaces()
selftests/namespaces: fix nsid tests
ns: drop custom reference count initialization for initial namespaces
pid: rely on common reference count behavior
ns: add asserts for initial namespace active reference counts
ns: add asserts for initial namespace reference counts
ns: make all reference counts on initial namespace a nop
ipc: enable is_ns_init_id() assertions
fs: use boolean to indicate anonymous mount namespace
ns: rename is_initial_namespace()
ns: make is_initial_namespace() argument const
nstree: use guards for ns_tree_lock
nstree: simplify owner list iteration
nstree: switch to new structures
nstree: add helper to operate on struct ns_tree_{node,root}
nstree: move nstree types into separate header
nstree: decouple from ns_common header
ns: move namespace types into separate header
...
While cleaning up some headers, I got a build error on this file:
init/calibrate.c:20:9: error: call to undeclared function 'kstrtoul'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
Update header inclusions to follow IWYU (Include What You Use) principle.
Link: https://lkml.kernel.org/r/20251124230607.1445421-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Replace simple_strtoul() with the recommended kstrtoul() for parsing the
'lpj=' boot parameter.
Check the return value of kstrtoul() and reject invalid values. This adds
error handling while preserving existing behavior for valid values, and
removes use of the deprecated simple_strtoul() helper.
Link: https://lkml.kernel.org/r/20251122114539.446937-2-thorsten.blum@linux.dev
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Move KHO to kernel/liveupdate/ in preparation of placing all Live Update
core kernel related files to the same place.
[pasha.tatashin@soleen.com: disable the menu when DEFERRED_STRUCT_PAGE_INIT]
Link: https://lkml.kernel.org/r/CA+CK2bAvh9Oa2SLfsbJ8zztpEjrgr_hr-uGgF1coy8yoibT39A@mail.gmail.com
Link: https://lkml.kernel.org/r/20251101142325.1326536-8-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Changyuan Lyu <changyuanl@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Pratyush Yadav <pratyush@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Simon Horman <horms@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zhu Yanjun <yanjun.zhu@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Having a lot of CID functionality specific members in struct task_struct
and struct mm_struct is not really making the code easier to read.
Encapsulate the CID specific parts in data structures and keep them
separate from the stuff they are embedded in.
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251119172549.131573768@linutronix.de
Quite a bit is already done by infrastructure changes (simple_link(),
simple_unlink()) - all that is left is replacing d_instantiate() +
pinning dget() (in ->symlink() and ->mknod()) with d_make_persistent(),
and, in case of shmem, using simple_unlink() and simple_link() in
->unlink() and ->link() resp., instead of open-coding those there.
Since d_make_persistent() accepts (and hashes) unhashed ones, shmem
situation gets simpler - we no longer care whether ->lookup() has hashed
the sucker.
With that done, we don't need kill_litter_super() for these filesystems
anymore - by the umount time all remaining dentries will be marked
persistent and kill_litter_super() will boil down to call of
kill_anon_super().
The same goes for devtmpfs and rootfs - they are handled by
ramfs or by shmem, depending upon config.
NB: strictly speaking, both devtmpfs and rootfs ought to use
ramfs_kill_sb() if they end up using ramfs; that's a separate
story and the only impact of "just use kill_{litter,anon}_super()"
is that we fail to free their sb->s_fs_info... on reboot.
That's orthogonal to the changes in this series - kill_litter_super()
is identical to kill_anon_super() for those at this point.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The generic test for CC_CAN_LINK assumes that all architectures use -m32
and -m64 to switch between 32-bit and 64-bit compilation. This is overly
simplistic. Architectures may use other flags (-mabi, -m31, etc.) or may
also require byte order handling (-mlittle-endian, -EL). Expressing all
of the different possibilities will be very complicated and brittle.
Instead allow architectures to supply their own logic which will be
easy to understand and evolve.
Both the boolean ARCH_HAS_CC_CAN_LINK and the string ARCH_USERFLAGS need
to be implemented as kconfig does not allow the reuse of string options.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20251114-kbuild-userprogs-bits-v3-3-4dee0d74d439@linutronix.de
Signed-off-by: Nicolas Schier <nsc@kernel.org>
The command to invoke scripts/cc-can-link.sh is very long and new usages
are about to be added.
Add a helper variable to make the code easier to read and maintain.
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20251114-kbuild-userprogs-bits-v3-2-4dee0d74d439@linutronix.de
Signed-off-by: Nicolas Schier <nsc@kernel.org>
In Rust 1.80, the previously unstable `slice::flatten` family of methods
have been stabilized and renamed to `slice::as_flattened`.
This creates an issue as we want to use `as_flattened`, but need to
support the MSRV (which at the moment is Rust 1.78) where it is named
`flatten`.
Solve this by enabling the `slice_flatten` feature, and providing an
`as_flattened` implementation through an extension trait for compiler
versions where it is not available.
The trait is then exported from the prelude, making the `as_flattened`
family of methods transparently available for all supported compiler
versions.
This extension trait can be removed once the MSRV passes 1.80.
Suggested-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/all/CANiq72kK4pG=O35NwxPNoTO17oRcg1yfGcvr3==Fi4edr+sfmw@mail.gmail.com/
Acked-by: Danilo Krummrich <dakr@kernel.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Message-ID: <20251110-gsp_boot-v9-8-8ae4058e3c0e@nvidia.com>
Message-ID: <20251104-b4-as-flattened-v3-1-6cb9c26b45cd@nvidia.com>
The kernel cmdline length is allowed to be longer than what printk can
handle. When this happens the cmdline that's printed to the kernel ring
buffer at bootup is cutoff and some kernel cmdline options are "hidden"
from the logs. This undercuts the usefulness of the log message.
Specifically, grepping for COMMAND_LINE_SIZE shows that 2048 is common and
some architectures even define it as 4096. s390 allows a CONFIG-based
maximum up to 1MB (though it's not expected that anyone will go over the
default max of 4096 [1]).
The maximum message pr_notice() seems to be able to handle (based on
experiment) is 1021 characters. This appears to be based on the current
value of PRINTKRB_RECORD_MAX as 1024 and the fact that pr_notice() spends
2 characters on the loglevel prefix and we have a '\n' at the end.
While it would be possible to increase the limits of printk() (and
therefore pr_notice()) somewhat, it doesn't appear possible to increase it
enough to fully include a 2048-character cmdline without breaking
userspace. Specifically on at least two tested userspaces (ChromeOS plus
the Debian-based distro I'm typing this message on) the `dmesg` tool reads
lines from `/dev/kmsg` in 2047-byte chunks. As per
`Documentation/ABI/testing/dev-kmsg`:
Every read() from the opened device node receives one record
of the kernel's printk buffer.
...
Messages in the record ring buffer get overwritten as whole,
there are never partial messages received by read().
We simply can't fit a 2048-byte cmdline plus the "Kernel command line:"
prefix plus info about time/log_level/etc in a 2047-byte read.
The above means that if we want to avoid the truncation we need to do some
type of wrapping of the cmdline when printing.
Add wrapping to the printout of the kernel command line. By default, the
wrapping is set to 1021 characters to avoid breaking anyone, but allow
wrapping to be set lower by a Kconfig knob
"CONFIG_CMDLINE_LOG_WRAP_IDEAL_LEN". Any tools that are correctly parsing
the cmdline today (because it is less than 1021 characters) will see no
difference in their behavior. The format of wrapped output is designed to
be matched by anyone using "grep" to search for the cmdline and also to be
easy for tools to handle. Anyone who is sure their tools (if any) handle
the wrapped format can choose a lower wrapping value and have prettier
output.
Setting CONFIG_CMDLINE_LOG_WRAP_IDEAL_LEN to 0 fully disables the wrapping
logic. This means that long command lines will be truncated again, but
this config could be set if command lines are expected to be long and
userspace is known not to handle parsing logs with the wrapping.
Wrapping is based on spaces, ignoring quotes. All lines are prefixed with
"Kernel command line: " and lines that are not the last line have a " \"
suffix added to them. The prefix and suffix count towards the line length
for wrapping purposes. The ideal length will be exceeded if no
appropriate place to wrap is found.
The wrapping function added here is fairly generic and could be made a
library function (somewhat like print_hex_dump()) if it's needed elsewhere
in the kernel. However, having printk() directly incorporate this
wrapping would be unlikely to be a good idea since it would break
printouts into more than one record without any obvious common line prefix
to tie lines together. It would also be extra overhead when, in general,
kernel log message should simply be kept smaller than 1021 bytes. For
some discussion on this topic, see responses to the v1 posting of this
patch [2].
[akpm@linux-foundation.org: make print_kernel_cmdline __init]
[dianders@chromium.org: v4]
Link: https://lkml.kernel.org/r/20251027082204.v4.1.I095f1e2c6c27f9f4de0b4841f725f356c643a13f@changeid
Link: https://lkml.kernel.org/r/20251023113257.v3.1.I095f1e2c6c27f9f4de0b4841f725f356c643a13f@changeid
Link: https://lore.kernel.org/r/20251021131633.26700Dd6-hca@linux.ibm.com [1]
Link: https://lore.kernel.org/r/CAD=FV=VNyt1zG_8pS64wgV8VkZWiWJymnZ-XCfkrfaAhhFSKcA@mail.gmail.com [2]
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Chant <achant@google.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Francesco Valla <francesco@valla.it>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: guoweikang <guoweikang.kernel@gmail.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Hendrik Farr <kernel@jfarr.cc>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Replace deprecated simple_strtoul() with kstrtouint() for better error
handling and input validation. Return 0 on parsing failure to indicate
invalid parameter, maintaining existing behavior for valid inputs.
The simple_strtoul() function is deprecated in favor of kstrtoint()
family functions which provide better error handling and are recommended
for new code and replacements.
Signed-off-by: Kaushlendra Kumar <kaushlendra.kumar@intel.com>
Link: https://patch.msgid.link/20251103080627.1844645-1-kaushlendra.kumar@intel.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Now that all bits and pieces are in place, hook the RSEQ handling fast path
function into exit_to_user_mode_prepare() after the TIF work bits have been
handled. If case of fast path failure, TIF_NOTIFY_RESUME has been raised
and the caller needs to take another turn through the TIF handling slow
path.
This only works for architectures which use the generic entry code.
Architectures who still have their own incomplete hacks are not supported
and won't be.
This results in the following improvements:
Kernel build Before After Reduction
exit to user 80692981 80514451
signal checks: 32581 121 99%
slowpath runs: 1201408 1.49% 198 0.00% 100%
fastpath runs: 675941 0.84% N/A
id updates: 1233989 1.53% 50541 0.06% 96%
cs checks: 1125366 1.39% 0 0.00% 100%
cs cleared: 1125366 100% 0 100%
cs fixup: 0 0% 0
RSEQ selftests Before After Reduction
exit to user: 386281778 387373750
signal checks: 35661203 0 100%
slowpath runs: 140542396 36.38% 100 0.00% 100%
fastpath runs: 9509789 2.51% N/A
id updates: 176203599 45.62% 9087994 2.35% 95%
cs checks: 175587856 45.46% 4728394 1.22% 98%
cs cleared: 172359544 98.16% 1319307 27.90% 99%
cs fixup: 3228312 1.84% 3409087 72.10%
The 'cs cleared' and 'cs fixup' percentages are not relative to the exit to
user invocations, they are relative to the actual 'cs check' invocations.
While some of this could have been avoided in the original code, like the
obvious clearing of CS when it's already clear, the main problem of going
through TIF_NOTIFY_RESUME cannot be solved. In some workloads the RSEQ
notify handler is invoked more than once before going out to user
space. Doing this once when everything has stabilized is the only solution
to avoid this.
The initial attempt to completely decouple it from the TIF work turned out
to be suboptimal for workloads, which do a lot of quick and short system
calls. Even if the fast path decision is only 4 instructions (including a
conditional branch), this adds up quickly and becomes measurable when the
rate for actually having to handle rseq is in the low single digit
percentage range of user/kernel transitions.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084307.701201365@linutronix.de
Config based debug is rarely turned on and is not available easily when
things go wrong.
Provide a static branch to allow permanent integration of debug mechanisms
along with the usual toggles in Kconfig, command line and debugfs.
Requested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084307.089270547@linutronix.de
Analyzing the call frequency without actually using tracing is helpful for
analysis of this infrastructure. The overhead is minimal as it just
increments a per CPU counter associated to each operation.
The debugfs readout provides a racy sum of all counters.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20251027084307.027916598@linutronix.de
Replace simple_strtol() with the recommended kstrtoint() for parsing the
'ramdisk_start=' boot parameter. Unlike simple_strtol(), which returns a
a long, kstrtoint() converts the string directly to an integer and
avoids implicit casting.
Check the return value of kstrtoint() and reject invalid values. This
adds error handling while preserving existing behavior for valid values,
and removes use of the deprecated simple_strtol() helper.
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
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Merge tag 'printk-for-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux
Pull printk updates from Petr Mladek:
- Add KUnit test for the printk ring buffer
- Fix the check of the maximal record size which is allowed to be
stored into the printk ring buffer. It prevents corruptions of the
ring buffer.
Note that printk() is on the safe side. The messages are limited by
1kB buffer and are always small enough for the minimal log buffer
size 4kB, see CONFIG_LOG_BUF_SHIFT definition.
* tag 'printk-for-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
printk: ringbuffer: Fix data block max size check
printk: kunit: support offstack cpumask
printk: kunit: Fix __counted_by() in struct prbtest_rbdata
printk: ringbuffer: Explain why the KUnit test ignores failed writes
printk: ringbuffer: Add KUnit test
- The 3 patch series "ida: Remove the ida_simple_xxx() API" from
Christophe Jaillet completes the removal of this legacy IDR API.
- The 9 patch series "panic: introduce panic status function family"
from Jinchao Wang provides a number of cleanups to the panic code and
its various helpers, which were rather ad-hoc and scattered all over the
place.
- The 5 patch series "tools/delaytop: implement real-time keyboard
interaction support" from Fan Yu adds a few nice user-facing usability
changes to the delaytop monitoring tool.
- The 3 patch series "efi: Fix EFI boot with kexec handover (KHO)" from
Evangelos Petrongonas fixes a panic which was happening with the
combination of EFI and KHO.
- The 2 patch series "Squashfs: performance improvement and a sanity
check" from Phillip Lougher teaches squashfs's lseek() about
SEEK_DATA/SEEK_HOLE. A mere 150x speedup was measured for a well-chosen
microbenchmark.
- Plus another 50-odd singleton patches all over the place.
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Merge tag 'mm-nonmm-stable-2025-10-02-15-29' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- "ida: Remove the ida_simple_xxx() API" from Christophe Jaillet
completes the removal of this legacy IDR API
- "panic: introduce panic status function family" from Jinchao Wang
provides a number of cleanups to the panic code and its various
helpers, which were rather ad-hoc and scattered all over the place
- "tools/delaytop: implement real-time keyboard interaction support"
from Fan Yu adds a few nice user-facing usability changes to the
delaytop monitoring tool
- "efi: Fix EFI boot with kexec handover (KHO)" from Evangelos
Petrongonas fixes a panic which was happening with the combination of
EFI and KHO
- "Squashfs: performance improvement and a sanity check" from Phillip
Lougher teaches squashfs's lseek() about SEEK_DATA/SEEK_HOLE. A mere
150x speedup was measured for a well-chosen microbenchmark
- plus another 50-odd singleton patches all over the place
* tag 'mm-nonmm-stable-2025-10-02-15-29' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (75 commits)
Squashfs: reject negative file sizes in squashfs_read_inode()
kallsyms: use kmalloc_array() instead of kmalloc()
MAINTAINERS: update Sibi Sankar's email address
Squashfs: add SEEK_DATA/SEEK_HOLE support
Squashfs: add additional inode sanity checking
lib/genalloc: fix device leak in of_gen_pool_get()
panic: remove CONFIG_PANIC_ON_OOPS_VALUE
ocfs2: fix double free in user_cluster_connect()
checkpatch: suppress strscpy warnings for userspace tools
cramfs: fix incorrect physical page address calculation
kernel: prevent prctl(PR_SET_PDEATHSIG) from racing with parent process exit
Squashfs: fix uninit-value in squashfs_get_parent
kho: only fill kimage if KHO is finalized
ocfs2: avoid extra calls to strlen() after ocfs2_sprintf_system_inode_name()
kernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64() paths
sched/task.h: fix the wrong comment on task_lock() nesting with tasklist_lock
coccinelle: platform_no_drv_owner: handle also built-in drivers
coccinelle: of_table: handle SPI device ID tables
lib/decompress: use designated initializers for struct compress_format
efi: support booting with kexec handover (KHO)
...
- Extend modules.builtin.modinfo to include module aliases from
MODULE_DEVICE_TABLE for builtin modules so that userspace tools (such
as kmod) can verify that a particular module alias will be handled by
a builtin module.
- Bump the minimum version of LLVM for building the kernel to 15.0.0.
- Upgrade several userspace API checks in headers_check.pl to errors.
- Unify and consolidate CONFIG_WERROR / W=e handling.
- Turn assembler and linker warnings into errors with CONFIG_WERROR /
W=e.
- Respect CONFIG_WERROR / W=e when building userspace programs
(userprogs).
- Enable -Werror unconditionally when building host programs
(hostprogs).
- Support copy_file_range() and data segment alignment in gen_init_cpio
to improve performance on filesystems that support reflinks such as
btrfs and XFS.
- Miscellaneous small changes to scripts and configuration files.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
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Merge tag 'kbuild-6.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux
Pull Kbuild updates from Nathan Chancellor:
- Extend modules.builtin.modinfo to include module aliases from
MODULE_DEVICE_TABLE for builtin modules so that userspace tools (such
as kmod) can verify that a particular module alias will be handled by
a builtin module
- Bump the minimum version of LLVM for building the kernel to 15.0.0
- Upgrade several userspace API checks in headers_check.pl to errors
- Unify and consolidate CONFIG_WERROR / W=e handling
- Turn assembler and linker warnings into errors with CONFIG_WERROR /
W=e
- Respect CONFIG_WERROR / W=e when building userspace programs
(userprogs)
- Enable -Werror unconditionally when building host programs
(hostprogs)
- Support copy_file_range() and data segment alignment in gen_init_cpio
to improve performance on filesystems that support reflinks such as
btrfs and XFS
- Miscellaneous small changes to scripts and configuration files
* tag 'kbuild-6.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (47 commits)
modpost: Initialize builtin_modname to stop SIGSEGVs
Documentation: kbuild: note CONFIG_DEBUG_EFI in reproducible builds
kbuild: vmlinux.unstripped should always depend on .vmlinux.export.o
modpost: Create modalias for builtin modules
modpost: Add modname to mod_device_table alias
scsi: Always define blogic_pci_tbl structure
kbuild: extract modules.builtin.modinfo from vmlinux.unstripped
kbuild: keep .modinfo section in vmlinux.unstripped
kbuild: always create intermediate vmlinux.unstripped
s390: vmlinux.lds.S: Reorder sections
KMSAN: Remove tautological checks
objtool: Drop noinstr hack for KCSAN_WEAK_MEMORY
lib/Kconfig.debug: Drop CLANG_VERSION check from DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
riscv: Remove ld.lld version checks from many TOOLCHAIN_HAS configs
riscv: Unconditionally use linker relaxation
riscv: Remove version check for LTO_CLANG selects
powerpc: Drop unnecessary initializations in __copy_inst_from_kernel_nofault()
mips: Unconditionally select ARCH_HAS_CURRENT_STACK_POINTER
arm64: Remove tautological LLVM Kconfig conditions
ARM: Clean up definition of ARM_HAS_GROUP_RELOCS
...
Linus Torvalds