If a single-threaded process exits do_notify_pidfd() will be called twice,
from exit_notify() and right after that from do_notify_parent().
1. Change exit_notify() to call do_notify_pidfd() if the exiting task is
not ptraced and it is not a group leader.
2. Change do_notify_parent() to call do_notify_pidfd() unconditionally.
If tsk is not ptraced, do_notify_parent() will only be called when it
is a group-leader and thread_group_empty() is true.
This means that if tsk is ptraced, do_notify_pidfd() will be called from
do_notify_parent() even if tsk is a delay_group_leader(). But this case is
less common, and apart from the unnecessary __wake_up() is harmless.
Granted, this unnecessary __wake_up() can be avoided, but I don't want to
do it in this patch because it's just a consequence of another historical
oddity: we notify the tracer even if !thread_group_empty(), but do_wait()
from debugger can't work until all other threads exit. With or without this
patch we should either eliminate do_notify_parent() in this case, or change
do_wait(WEXITED) to untrace the ptraced delay_group_leader() at least when
ptrace_reparented().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20250323171955.GA834@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull core x86 updates from Ingo Molnar:
"x86 CPU features support:
- Generate the <asm/cpufeaturemasks.h> header based on build config
(H. Peter Anvin, Xin Li)
- x86 CPUID parsing updates and fixes (Ahmed S. Darwish)
- Introduce the 'setcpuid=' boot parameter (Brendan Jackman)
- Enable modifying CPU bug flags with '{clear,set}puid=' (Brendan
Jackman)
- Utilize CPU-type for CPU matching (Pawan Gupta)
- Warn about unmet CPU feature dependencies (Sohil Mehta)
- Prepare for new Intel Family numbers (Sohil Mehta)
Percpu code:
- Standardize & reorganize the x86 percpu layout and related cleanups
(Brian Gerst)
- Convert the stackprotector canary to a regular percpu variable
(Brian Gerst)
- Add a percpu subsection for cache hot data (Brian Gerst)
- Unify __pcpu_op{1,2}_N() macros to __pcpu_op_N() (Uros Bizjak)
- Construct __percpu_seg_override from __percpu_seg (Uros Bizjak)
MM:
- Add support for broadcast TLB invalidation using AMD's INVLPGB
instruction (Rik van Riel)
- Rework ROX cache to avoid writable copy (Mike Rapoport)
- PAT: restore large ROX pages after fragmentation (Kirill A.
Shutemov, Mike Rapoport)
- Make memremap(MEMREMAP_WB) map memory as encrypted by default
(Kirill A. Shutemov)
- Robustify page table initialization (Kirill A. Shutemov)
- Fix flush_tlb_range() when used for zapping normal PMDs (Jann Horn)
- Clear _PAGE_DIRTY for kernel mappings when we clear _PAGE_RW
(Matthew Wilcox)
KASLR:
- x86/kaslr: Reduce KASLR entropy on most x86 systems, to support PCI
BAR space beyond the 10TiB region (CONFIG_PCI_P2PDMA=y) (Balbir
Singh)
CPU bugs:
- Implement FineIBT-BHI mitigation (Peter Zijlstra)
- speculation: Simplify and make CALL_NOSPEC consistent (Pawan Gupta)
- speculation: Add a conditional CS prefix to CALL_NOSPEC (Pawan
Gupta)
- RFDS: Exclude P-only parts from the RFDS affected list (Pawan
Gupta)
System calls:
- Break up entry/common.c (Brian Gerst)
- Move sysctls into arch/x86 (Joel Granados)
Intel LAM support updates: (Maciej Wieczor-Retman)
- selftests/lam: Move cpu_has_la57() to use cpuinfo flag
- selftests/lam: Skip test if LAM is disabled
- selftests/lam: Test get_user() LAM pointer handling
AMD SMN access updates:
- Add SMN offsets to exclusive region access (Mario Limonciello)
- Add support for debugfs access to SMN registers (Mario Limonciello)
- Have HSMP use SMN through AMD_NODE (Yazen Ghannam)
Power management updates: (Patryk Wlazlyn)
- Allow calling mwait_play_dead with an arbitrary hint
- ACPI/processor_idle: Add FFH state handling
- intel_idle: Provide the default enter_dead() handler
- Eliminate mwait_play_dead_cpuid_hint()
Build system:
- Raise the minimum GCC version to 8.1 (Brian Gerst)
- Raise the minimum LLVM version to 15.0.0 (Nathan Chancellor)
Kconfig: (Arnd Bergmann)
- Add cmpxchg8b support back to Geode CPUs
- Drop 32-bit "bigsmp" machine support
- Rework CONFIG_GENERIC_CPU compiler flags
- Drop configuration options for early 64-bit CPUs
- Remove CONFIG_HIGHMEM64G support
- Drop CONFIG_SWIOTLB for PAE
- Drop support for CONFIG_HIGHPTE
- Document CONFIG_X86_INTEL_MID as 64-bit-only
- Remove old STA2x11 support
- Only allow CONFIG_EISA for 32-bit
Headers:
- Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI and non-UAPI
headers (Thomas Huth)
Assembly code & machine code patching:
- x86/alternatives: Simplify alternative_call() interface (Josh
Poimboeuf)
- x86/alternatives: Simplify callthunk patching (Peter Zijlstra)
- KVM: VMX: Use named operands in inline asm (Josh Poimboeuf)
- x86/hyperv: Use named operands in inline asm (Josh Poimboeuf)
- x86/traps: Cleanup and robustify decode_bug() (Peter Zijlstra)
- x86/kexec: Merge x86_32 and x86_64 code using macros from
<asm/asm.h> (Uros Bizjak)
- Use named operands in inline asm (Uros Bizjak)
- Improve performance by using asm_inline() for atomic locking
instructions (Uros Bizjak)
Earlyprintk:
- Harden early_serial (Peter Zijlstra)
NMI handler:
- Add an emergency handler in nmi_desc & use it in
nmi_shootdown_cpus() (Waiman Long)
Miscellaneous fixes and cleanups:
- by Ahmed S. Darwish, Andy Shevchenko, Ard Biesheuvel, Artem
Bityutskiy, Borislav Petkov, Brendan Jackman, Brian Gerst, Dan
Carpenter, Dr. David Alan Gilbert, H. Peter Anvin, Ingo Molnar,
Josh Poimboeuf, Kevin Brodsky, Mike Rapoport, Lukas Bulwahn, Maciej
Wieczor-Retman, Max Grobecker, Patryk Wlazlyn, Pawan Gupta, Peter
Zijlstra, Philip Redkin, Qasim Ijaz, Rik van Riel, Thomas Gleixner,
Thorsten Blum, Tom Lendacky, Tony Luck, Uros Bizjak, Vitaly
Kuznetsov, Xin Li, liuye"
* tag 'x86-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (211 commits)
zstd: Increase DYNAMIC_BMI2 GCC version cutoff from 4.8 to 11.0 to work around compiler segfault
x86/asm: Make asm export of __ref_stack_chk_guard unconditional
x86/mm: Only do broadcast flush from reclaim if pages were unmapped
perf/x86/intel, x86/cpu: Replace Pentium 4 model checks with VFM ones
perf/x86/intel, x86/cpu: Simplify Intel PMU initialization
x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in non-UAPI headers
x86/headers: Replace __ASSEMBLY__ with __ASSEMBLER__ in UAPI headers
x86/locking/atomic: Improve performance by using asm_inline() for atomic locking instructions
x86/asm: Use asm_inline() instead of asm() in clwb()
x86/asm: Use CLFLUSHOPT and CLWB mnemonics in <asm/special_insns.h>
x86/hweight: Use asm_inline() instead of asm()
x86/hweight: Use ASM_CALL_CONSTRAINT in inline asm()
x86/hweight: Use named operands in inline asm()
x86/stackprotector/64: Only export __ref_stack_chk_guard on CONFIG_SMP
x86/head/64: Avoid Clang < 17 stack protector in startup code
x86/kexec: Merge x86_32 and x86_64 code using macros from <asm/asm.h>
x86/runtime-const: Add the RUNTIME_CONST_PTR assembly macro
x86/cpu/intel: Limit the non-architectural constant_tsc model checks
x86/mm/pat: Replace Intel x86_model checks with VFM ones
x86/cpu/intel: Fix fast string initialization for extended Families
...
Pull performance events updates from Ingo Molnar:
"Core:
- Move perf_event sysctls into kernel/events/ (Joel Granados)
- Use POLLHUP for pinned events in error (Namhyung Kim)
- Avoid the read if the count is already updated (Peter Zijlstra)
- Allow the EPOLLRDNORM flag for poll (Tao Chen)
- locking/percpu-rwsem: Add guard support [ NOTE: this got
(mis-)merged into the perf tree due to related work ] (Peter
Zijlstra)
perf_pmu_unregister() related improvements: (Peter Zijlstra)
- Simplify the perf_event_alloc() error path
- Simplify the perf_pmu_register() error path
- Simplify perf_pmu_register()
- Simplify perf_init_event()
- Simplify perf_event_alloc()
- Merge struct pmu::pmu_disable_count into struct
perf_cpu_pmu_context::pmu_disable_count
- Add this_cpc() helper
- Introduce perf_free_addr_filters()
- Robustify perf_event_free_bpf_prog()
- Simplify the perf_mmap() control flow
- Further simplify perf_mmap()
- Remove retry loop from perf_mmap()
- Lift event->mmap_mutex in perf_mmap()
- Detach 'struct perf_cpu_pmu_context' and 'struct pmu' lifetimes
- Fix perf_mmap() failure path
Uprobes:
- Harden x86 uretprobe syscall trampoline check (Jiri Olsa)
- Remove redundant spinlock in uprobe_deny_signal() (Liao Chang)
- Remove the spinlock within handle_singlestep() (Liao Chang)
x86 Intel PMU enhancements:
- Support PEBS counters snapshotting (Kan Liang)
- Fix intel_pmu_read_event() (Kan Liang)
- Extend per event callchain limit to branch stack (Kan Liang)
- Fix system-wide LBR profiling (Kan Liang)
- Allocate bts_ctx only if necessary (Li RongQing)
- Apply static call for drain_pebs (Peter Zijlstra)
x86 AMD PMU enhancements: (Ravi Bangoria)
- Remove pointless sample period check
- Fix ->config to sample period calculation for OP PMU
- Fix perf_ibs_op.cnt_mask for CurCnt
- Don't allow freq mode event creation through ->config interface
- Add PMU specific minimum period
- Add ->check_period() callback
- Ceil sample_period to min_period
- Add support for OP Load Latency Filtering
- Update DTLB/PageSize decode logic
Hardware breakpoints:
- Return EOPNOTSUPP for unsupported breakpoint type (Saket Kumar
Bhaskar)
Hardlockup detector improvements: (Li Huafei)
- perf_event memory leak
- Warn if watchdog_ev is leaked
Fixes and cleanups:
- Misc fixes and cleanups (Andy Shevchenko, Kan Liang, Peter
Zijlstra, Ravi Bangoria, Thorsten Blum, XieLudan)"
* tag 'perf-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (55 commits)
perf: Fix __percpu annotation
perf: Clean up pmu specific data
perf/x86: Remove swap_task_ctx()
perf/x86/lbr: Fix shorter LBRs call stacks for the system-wide mode
perf: Supply task information to sched_task()
perf: attach/detach PMU specific data
locking/percpu-rwsem: Add guard support
perf: Save PMU specific data in task_struct
perf: Extend per event callchain limit to branch stack
perf/ring_buffer: Allow the EPOLLRDNORM flag for poll
perf/core: Use POLLHUP for pinned events in error
perf/core: Use sysfs_emit() instead of scnprintf()
perf/core: Remove optional 'size' arguments from strscpy() calls
perf/x86/intel/bts: Check if bts_ctx is allocated when calling BTS functions
uprobes/x86: Harden uretprobe syscall trampoline check
watchdog/hardlockup/perf: Warn if watchdog_ev is leaked
watchdog/hardlockup/perf: Fix perf_event memory leak
perf/x86: Annotate struct bts_buffer::buf with __counted_by()
perf/core: Clean up perf_try_init_event()
perf/core: Fix perf_mmap() failure path
...
Pull scheduler updates from Ingo Molnar:
"Core & fair scheduler changes:
- Cancel the slice protection of the idle entity (Zihan Zhou)
- Reduce the default slice to avoid tasks getting an extra tick
(Zihan Zhou)
- Force propagating min_slice of cfs_rq when {en,de}queue tasks
(Tianchen Ding)
- Refactor can_migrate_task() to elimate looping (I Hsin Cheng)
- Add unlikey branch hints to several system calls (Colin Ian King)
- Optimize current_clr_polling() on certain architectures (Yujun
Dong)
Deadline scheduler: (Juri Lelli)
- Remove redundant dl_clear_root_domain call
- Move dl_rebuild_rd_accounting to cpuset.h
Uclamp:
- Use the uclamp_is_used() helper instead of open-coding it (Xuewen
Yan)
- Optimize sched_uclamp_used static key enabling (Xuewen Yan)
Scheduler topology support: (Juri Lelli)
- Ignore special tasks when rebuilding domains
- Add wrappers for sched_domains_mutex
- Generalize unique visiting of root domains
- Rebuild root domain accounting after every update
- Remove partition_and_rebuild_sched_domains
- Stop exposing partition_sched_domains_locked
RSEQ: (Michael Jeanson)
- Update kernel fields in lockstep with CONFIG_DEBUG_RSEQ=y
- Fix segfault on registration when rseq_cs is non-zero
- selftests: Add rseq syscall errors test
- selftests: Ensure the rseq ABI TLS is actually 1024 bytes
Membarriers:
- Fix redundant load of membarrier_state (Nysal Jan K.A.)
Scheduler debugging:
- Introduce and use preempt_model_str() (Sebastian Andrzej Siewior)
- Make CONFIG_SCHED_DEBUG unconditional (Ingo Molnar)
Fixes and cleanups:
- Always save/restore x86 TSC sched_clock() on suspend/resume
(Guilherme G. Piccoli)
- Misc fixes and cleanups (Thorsten Blum, Juri Lelli, Sebastian
Andrzej Siewior)"
* tag 'sched-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits)
cpuidle, sched: Use smp_mb__after_atomic() in current_clr_polling()
sched/debug: Remove CONFIG_SCHED_DEBUG
sched/debug: Remove CONFIG_SCHED_DEBUG from self-test config files
sched/debug, Documentation: Remove (most) CONFIG_SCHED_DEBUG references from documentation
sched/debug: Make CONFIG_SCHED_DEBUG functionality unconditional
sched/debug: Make 'const_debug' tunables unconditional __read_mostly
sched/debug: Change SCHED_WARN_ON() to WARN_ON_ONCE()
rseq/selftests: Fix namespace collision with rseq UAPI header
include/{topology,cpuset}: Move dl_rebuild_rd_accounting to cpuset.h
sched/topology: Stop exposing partition_sched_domains_locked
cgroup/cpuset: Remove partition_and_rebuild_sched_domains
sched/topology: Remove redundant dl_clear_root_domain call
sched/deadline: Rebuild root domain accounting after every update
sched/deadline: Generalize unique visiting of root domains
sched/topology: Wrappers for sched_domains_mutex
sched/deadline: Ignore special tasks when rebuilding domains
tracing: Use preempt_model_str()
xtensa: Rely on generic printing of preemption model
x86: Rely on generic printing of preemption model
s390: Rely on generic printing of preemption model
...
Pull objtool updates from Ingo Molnar:
- The biggest change is the new option to automatically fail the build
on objtool warnings: CONFIG_OBJTOOL_WERROR.
While there are no currently known unfixed false positives left, such
an expansion in the severity of objtool warnings inevitably creates a
risk of build failures, so it's disabled by default and depends on
!COMPILE_TEST, so it shouldn't be enabled on
allyesconfig/allmodconfig builds and won't be forced on people who
just accept build-time defaults in 'make oldconfig'.
While the option is strongly recommended, only people who enable it
explicitly should see it.
(Josh Poimboeuf)
- Disable branch profiling in noinstr code with a broad brush that
includes all of arch/x86/ and kernel/sched/. (Josh Poimboeuf)
- Create backup object files on objtool errors and print exact objtool
arguments to make failure analysis easier (Josh Poimboeuf)
- Improve noreturn handling (Josh Poimboeuf)
- Improve rodata handling (Tiezhu Yang)
- Support jump tables, switch tables and goto tables on LoongArch
(Tiezhu Yang)
- Misc cleanups and fixes (Josh Poimboeuf, David Engraf, Ingo Molnar)
* tag 'objtool-core-2025-03-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
tracing: Disable branch profiling in noinstr code
objtool: Use O_CREAT with explicit mode mask
objtool: Add CONFIG_OBJTOOL_WERROR
objtool: Create backup on error and print args
objtool: Change "warning:" to "error:" for --Werror
objtool: Add --Werror option
objtool: Add --output option
objtool: Upgrade "Linked object detected" warning to error
objtool: Consolidate option validation
objtool: Remove --unret dependency on --rethunk
objtool: Increase per-function WARN_FUNC() rate limit
objtool: Update documentation
objtool: Improve __noreturn annotation warning
objtool: Fix error handling inconsistencies in check()
x86/traps: Make exc_double_fault() consistently noreturn
LoongArch: Enable jump table for objtool
objtool/LoongArch: Add support for goto table
objtool/LoongArch: Add support for switch table
objtool: Handle PC relative relocation type
objtool: Handle different entry size of rodata
...
Pull RCU updates from Boqun Feng:
"Documentation:
- Add broken-timing possibility to stallwarn.rst
- Improve discussion of this_cpu_ptr(), add raw_cpu_ptr()
- Document self-propagating callbacks
- Point call_srcu() to call_rcu() for detailed memory ordering
- Add CONFIG_RCU_LAZY delays to call_rcu() kernel-doc header
- Clarify RCU_LAZY and RCU_LAZY_DEFAULT_OFF help text
- Remove references to old grace-period-wait primitives
srcu:
- Introduce srcu_read_{un,}lock_fast(), which is similar to
srcu_read_{un,}lock_lite(): avoid smp_mb()s in lock and unlock
at the cost of calling synchronize_rcu() in synchronize_srcu()
Moreover, by returning the percpu offset of the counter at
srcu_read_lock_fast() time, srcu_read_unlock_fast() can avoid
extra pointer dereferencing, which makes it faster than
srcu_read_{un,}lock_lite()
srcu_read_{un,}lock_fast() are intended to replace
rcu_read_{un,}lock_trace() if possible
RCU torture:
- Add get_torture_init_jiffies() to return the start time of the test
- Add a test_boost_holdoff module parameter to allow delaying
boosting tests when building rcutorture as built-in
- Add grace period sequence number logging at the beginning and end
of failure/close-call results
- Switch to hexadecimal for the expedited grace period sequence
number in the rcu_exp_grace_period trace point
- Make cur_ops->format_gp_seqs take buffer length
- Move RCU_TORTURE_TEST_{CHK_RDR_STATE,LOG_CPU} to bool
- Complain when invalid SRCU reader_flavor is specified
- Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing, which forces SRCU
uses atomics even when percpu ops are NMI safe, and use the Kconfig
for SRCU lockdep testing
Misc:
- Split rcu_report_exp_cpu_mult() mask parameter and use for tracing
- Remove READ_ONCE() for rdp->gpwrap access in __note_gp_changes()
- Fix get_state_synchronize_rcu_full() GP-start detection
- Move RCU Tasks self-tests to core_initcall()
- Print segment lengths in show_rcu_nocb_gp_state()
- Make RCU watch ct_kernel_exit_state() warning
- Flush console log from kernel_power_off()
- rcutorture: Allow a negative value for nfakewriters
- rcu: Update TREE05.boot to test normal synchronize_rcu()
- rcu: Use _full() API to debug synchronize_rcu()
Make RCU handle PREEMPT_LAZY better:
- Fix header guard for rcu_all_qs()
- rcu: Rename PREEMPT_AUTO to PREEMPT_LAZY
- Update __cond_resched comment about RCU quiescent states
- Handle unstable rdp in rcu_read_unlock_strict()
- Handle quiescent states for PREEMPT_RCU=n, PREEMPT_COUNT=y
- osnoise: Provide quiescent states
- Adjust rcutorture with possible PREEMPT_RCU=n && PREEMPT_COUNT=y
combination
- Limit PREEMPT_RCU configurations
- Make rcutorture senario TREE07 and senario TREE10 use
PREEMPT_LAZY=y"
* tag 'rcu-next-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: (59 commits)
rcutorture: Make scenario TREE07 build CONFIG_PREEMPT_LAZY=y
rcutorture: Make scenario TREE10 build CONFIG_PREEMPT_LAZY=y
rcu: limit PREEMPT_RCU configurations
rcutorture: Update ->extendables check for lazy preemption
rcutorture: Update rcutorture_one_extend_check() for lazy preemption
osnoise: provide quiescent states
rcu: Use _full() API to debug synchronize_rcu()
rcu: Update TREE05.boot to test normal synchronize_rcu()
rcutorture: Allow a negative value for nfakewriters
Flush console log from kernel_power_off()
context_tracking: Make RCU watch ct_kernel_exit_state() warning
rcu/nocb: Print segment lengths in show_rcu_nocb_gp_state()
rcu-tasks: Move RCU Tasks self-tests to core_initcall()
rcu: Fix get_state_synchronize_rcu_full() GP-start detection
torture: Make SRCU lockdep testing use srcu_read_lock_nmisafe()
srcu: Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing
rcutorture: Complain when invalid SRCU reader_flavor is specified
rcutorture: Move RCU_TORTURE_TEST_{CHK_RDR_STATE,LOG_CPU} to bool
rcutorture: Make cur_ops->format_gp_seqs take buffer length
rcutorture: Add ftrace-compatible timestamp to GP# failure/close-call output
...
Pull stop-machine update from Paul McKenney:
- Add a comment for the call to rcu_momentary_eqs() from
multi_cpu_stop() explaining that its purpose is to suppress
false-positive RCU CPU stall warnings
* tag 'stop-machine.2025.03.21a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
stop-machine: Add comment for rcu_momentary_eqs()
Pull sched_ext updates from Tejun Heo:
- Add mechanism to count and report internal events. This significantly
improves visibility on subtle corner conditions.
- The default idle CPU selection logic is revamped and improved in
multiple ways including being made topology aware.
- sched_ext was disabling ttwu_queue for simplicity, which can be
costly when hardware topology is more complex. Implement
SCX_OPS_ALLOWED_QUEUED_WAKEUP so that BPF schedulers can selectively
enable ttwu_queue.
- tools/sched_ext updates to improve compatibility among others.
- Other misc updates and fixes.
- sched_ext/for-6.14-fixes were pulled a few times to receive
prerequisite fixes and resolve conflicts.
* tag 'sched_ext-for-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: (42 commits)
sched_ext: idle: Refactor scx_select_cpu_dfl()
sched_ext: idle: Honor idle flags in the built-in idle selection policy
sched_ext: Skip per-CPU tasks in scx_bpf_reenqueue_local()
sched_ext: Add trace point to track sched_ext core events
sched_ext: Change the event type from u64 to s64
sched_ext: Documentation: add task lifecycle summary
tools/sched_ext: Provide a compatible helper for scx_bpf_events()
selftests/sched_ext: Add NUMA-aware scheduler test
tools/sched_ext: Provide consistent access to scx flags
sched_ext: idle: Fix scx_bpf_pick_any_cpu_node() behavior
sched_ext: idle: Introduce scx_bpf_nr_node_ids()
sched_ext: idle: Introduce node-aware idle cpu kfunc helpers
sched_ext: idle: Per-node idle cpumasks
sched_ext: idle: Introduce SCX_OPS_BUILTIN_IDLE_PER_NODE
sched_ext: idle: Make idle static keys private
sched/topology: Introduce for_each_node_numadist() iterator
mm/numa: Introduce nearest_node_nodemask()
nodemask: numa: reorganize inclusion path
nodemask: add nodes_copy()
tools/sched_ext: Sync with scx repo
...
Pull cgroup updates from Tejun Heo:
- Add deprecation info messages to cgroup1-only features
- rstat updates including a bug fix and breaking up a critical section
to reduce interrupt latency impact
- Other misc and doc updates
* tag 'cgroup-for-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: rstat: Cleanup flushing functions and locking
cgroup/rstat: avoid disabling irqs for O(num_cpu)
mm: Fix a build breakage in memcontrol-v1.c
blk-cgroup: Simplify policy files registration
cgroup: Update file naming comment
cgroup: Add deprecation message to legacy freezer controller
mm: Add transformation message for per-memcg swappiness
RFC cgroup/cpuset-v1: Add deprecation messages to sched_relax_domain_level
cgroup/cpuset-v1: Add deprecation messages to memory_migrate
cgroup/cpuset-v1: Add deprecation messages to mem_exclusive and mem_hardwall
cgroup: Print message when /proc/cgroups is read on v2-only system
cgroup/blkio: Add deprecation messages to reset_stats
cgroup/cpuset-v1: Add deprecation messages to memory_spread_page and memory_spread_slab
cgroup/cpuset-v1: Add deprecation messages to sched_load_balance and memory_pressure_enabled
cgroup, docs: Be explicit about independence of RT_GROUP_SCHED and non-cpu controllers
cgroup/rstat: Fix forceidle time in cpu.stat
cgroup/misc: Remove unused misc_cg_res_total_usage
cgroup/cpuset: Move procfs cpuset attribute under cgroup-v1.c
cgroup: update comment about dropping cgroup kn refs
Pull slab updates from Vlastimil Babka:
- Move the TINY_RCU kvfree_rcu() implementation from RCU to SLAB
subsystem and cleanup its integration (Vlastimil Babka)
Following the move of the TREE_RCU batching kvfree_rcu()
implementation in 6.14, move also the simpler TINY_RCU variant.
Refactor the #ifdef guards so that the simple implementation is also
used with SLUB_TINY.
Remove the need for RCU to recognize fake callback function pointers
(__is_kvfree_rcu_offset()) when handling call_rcu() by implementing a
callback that calculates the object's address from the embedded
rcu_head address without knowing its offset.
- Improve kmalloc cache randomization in kvmalloc (GONG Ruiqi)
Due to an extra layer of function call, all kvmalloc() allocations
used the same set of random caches. Thanks to moving the kvmalloc()
implementation to slub.c, this is improved and randomization now
works for kvmalloc.
- Various improvements to debugging, testing and other cleanups (Hyesoo
Yu, Lilith Gkini, Uladzislau Rezki, Matthew Wilcox, Kevin Brodsky, Ye
Bin)
* tag 'slab-for-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
slub: Handle freelist cycle in on_freelist()
mm/slab: call kmalloc_noprof() unconditionally in kmalloc_array_noprof()
slab: Mark large folios for debugging purposes
kunit, slub: Add test_kfree_rcu_wq_destroy use case
mm, slab: cleanup slab_bug() parameters
mm: slub: call WARN() when detecting a slab corruption
mm: slub: Print the broken data before restoring them
slab: Achieve better kmalloc caches randomization in kvmalloc
slab: Adjust placement of __kvmalloc_node_noprof
mm/slab: simplify SLAB_* flag handling
slab: don't batch kvfree_rcu() with SLUB_TINY
rcu, slab: use a regular callback function for kvfree_rcu
rcu: remove trace_rcu_kvfree_callback
slab, rcu: move TINY_RCU variant of kvfree_rcu() to SLAB
Pull seccomp updates from Kees Cook:
- avoid the lock trip seccomp_filter_release in common case (Mateusz
Guzik)
- remove unused 'sd' argument through-out (Oleg Nesterov)
- selftests/seccomp: Add hard-coded __NR_uretprobe for x86_64
* tag 'seccomp-v6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
seccomp: avoid the lock trip seccomp_filter_release in common case
seccomp: remove the 'sd' argument from __seccomp_filter()
seccomp: remove the 'sd' argument from __secure_computing()
seccomp: fix the __secure_computing() stub for !HAVE_ARCH_SECCOMP_FILTER
seccomp/mips: change syscall_trace_enter() to use secure_computing()
selftests/seccomp: Add hard-coded __NR_uretprobe for x86_64
Pull hardening updates from Kees Cook:
"As usual, it's scattered changes all over. Patches touching things
outside of our traditional areas in the tree have been Acked by
maintainers or were trivial changes:
- loadpin: remove unsupported MODULE_COMPRESS_NONE (Arulpandiyan
Vadivel)
- samples/check-exec: Fix script name (Mickaël Salaün)
- yama: remove needless locking in yama_task_prctl() (Oleg Nesterov)
- lib/string_choices: Sort by function name (R Sundar)
- hardening: Allow default HARDENED_USERCOPY to be set at compile
time (Mel Gorman)
- uaccess: Split out compile-time checks into ucopysize.h
- kbuild: clang: Support building UM with SUBARCH=i386
- x86: Enable i386 FORTIFY_SOURCE on Clang 16+
- ubsan/overflow: Rework integer overflow sanitizer option
- Add missing __nonstring annotations for callers of
memtostr*()/strtomem*()
- Add __must_be_noncstr() and have memtostr*()/strtomem*() check for
it
- Introduce __nonstring_array for silencing future GCC 15 warnings"
* tag 'hardening-v6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (26 commits)
compiler_types: Introduce __nonstring_array
hardening: Enable i386 FORTIFY_SOURCE on Clang 16+
x86/build: Remove -ffreestanding on i386 with GCC
ubsan/overflow: Enable ignorelist parsing and add type filter
ubsan/overflow: Enable pattern exclusions
ubsan/overflow: Rework integer overflow sanitizer option to turn on everything
samples/check-exec: Fix script name
yama: don't abuse rcu_read_lock/get_task_struct in yama_task_prctl()
kbuild: clang: Support building UM with SUBARCH=i386
loadpin: remove MODULE_COMPRESS_NONE as it is no longer supported
lib/string_choices: Rearrange functions in sorted order
string.h: Validate memtostr*()/strtomem*() arguments more carefully
compiler.h: Introduce __must_be_noncstr()
nilfs2: Mark on-disk strings as nonstring
uapi: stddef.h: Introduce __kernel_nonstring
x86/tdx: Mark message.bytes as nonstring
string: kunit: Mark nonstring test strings as __nonstring
scsi: qla2xxx: Mark device strings as nonstring
scsi: mpt3sas: Mark device strings as nonstring
scsi: mpi3mr: Mark device strings as nonstring
...
Pull execve updates from Kees Cook:
- elf: Define and use note name macros (Akihiko Odaki)
- elf: add remaining SHF_ flag macros (Timur Tabi)
- binfmt: Remove loader from linux_binprm struct (Yonatan Goldschmidt)
- binfmt_elf_fdpic: fix variable set but not used warning (sunliming)
* tag 'execve-v6.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
binfmt_elf_fdpic: fix variable set but not used warning
elf: add remaining SHF_ flag macros
binfmt: Remove loader from linux_binprm struct
crash: Remove KEXEC_CORE_NOTE_NAME
s390/crash: Use note name macros
crash: Use note name macros
powerpc/crash: Use note name macros
binfmt_elf: Use note name macros
elf: Define note name macros
Pull tasklist_lock optimizations from Christian Brauner:
"According to the performance testbots this brings a 23% performance
increase when creating new processes:
- Reduce tasklist_lock hold time on exit:
- Perform add_device_randomness() without tasklist_lock
- Perform free_pid() calls outside of tasklist_lock
- Drop irq disablement around pidmap_lock
- Add some tasklist_lock asserts
- Call flush_sigqueue() lockless by changing release_task()
- Don't pointlessly clear TIF_SIGPENDING in __exit_signal() ->
clear_tsk_thread_flag()"
* tag 'kernel-6.15-rc1.tasklist_lock' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
pid: drop irq disablement around pidmap_lock
pid: perform free_pid() calls outside of tasklist_lock
pid: sprinkle tasklist_lock asserts
exit: hoist get_pid() in release_task() outside of tasklist_lock
exit: perform add_device_randomness() without tasklist_lock
exit: kill the pointless __exit_signal()->clear_tsk_thread_flag(TIF_SIGPENDING)
exit: change the release_task() paths to call flush_sigqueue() lockless
Pull vfs async dir updates from Christian Brauner:
"This contains cleanups that fell out of the work from async directory
handling:
- Change kern_path_locked() and user_path_locked_at() to never return
a negative dentry. This simplifies the usability of these helpers
in various places
- Drop d_exact_alias() from the remaining place in NFS where it is
still used. This also allows us to drop the d_exact_alias() helper
completely
- Drop an unnecessary call to fh_update() from nfsd_create_locked()
- Change i_op->mkdir() to return a struct dentry
Change vfs_mkdir() to return a dentry provided by the filesystems
which is hashed and positive. This allows us to reduce the number
of cases where the resulting dentry is not positive to very few
cases. The code in these places becomes simpler and easier to
understand.
- Repack DENTRY_* and LOOKUP_* flags"
* tag 'vfs-6.15-rc1.async.dir' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
doc: fix inline emphasis warning
VFS: Change vfs_mkdir() to return the dentry.
nfs: change mkdir inode_operation to return alternate dentry if needed.
fuse: return correct dentry for ->mkdir
ceph: return the correct dentry on mkdir
hostfs: store inode in dentry after mkdir if possible.
Change inode_operations.mkdir to return struct dentry *
nfsd: drop fh_update() from S_IFDIR branch of nfsd_create_locked()
nfs/vfs: discard d_exact_alias()
VFS: add common error checks to lookup_one_qstr_excl()
VFS: change kern_path_locked() and user_path_locked_at() to never return negative dentry
VFS: repack LOOKUP_ bit flags.
VFS: repack DENTRY_ flags.
Pull vfs pidfs updates from Christian Brauner:
- Allow retrieving exit information after a process has been reaped
through pidfds via the new PIDFD_INTO_EXIT extension for the
PIDFD_GET_INFO ioctl. Various tools need access to information about
a process/task even after it has already been reaped.
Pidfd polling allows waiting on either task exit or for a task to
have been reaped. The contract for PIDFD_INFO_EXIT is simply that
EPOLLHUP must be observed before exit information can be retrieved,
i.e., exit information is only provided once the task has been reaped
and then can be retrieved as long as the pidfd is open.
- Add PIDFD_SELF_{THREAD,THREAD_GROUP} sentinels allowing userspace to
forgo allocating a file descriptor for their own process. This is
useful in scenarios where users want to act on their own process
through pidfds and is akin to AT_FDCWD.
- Improve premature thread-group leader and subthread exec behavior
when polling on pidfds:
(1) During a multi-threaded exec by a subthread, i.e.,
non-thread-group leader thread, all other threads in the
thread-group including the thread-group leader are killed and the
struct pid of the thread-group leader will be taken over by the
subthread that called exec. IOW, two tasks change their TIDs.
(2) A premature thread-group leader exit means that the thread-group
leader exited before all of the other subthreads in the
thread-group have exited.
Both cases lead to inconsistencies for pidfd polling with
PIDFD_THREAD. Any caller that holds a PIDFD_THREAD pidfd to the
current thread-group leader may or may not see an exit notification
on the file descriptor depending on when poll is performed. If the
poll is performed before the exec of the subthread has concluded an
exit notification is generated for the old thread-group leader. If
the poll is performed after the exec of the subthread has concluded
no exit notification is generated for the old thread-group leader.
The correct behavior is to simply not generate an exit notification
on the struct pid of a subhthread exec because the struct pid is
taken over by the subthread and thus remains alive.
But this is difficult to handle because a thread-group may exit
premature as mentioned in (2). In that case an exit notification is
reliably generated but the subthreads may continue to run for an
indeterminate amount of time and thus also may exec at some point.
After this pull no exit notifications will be generated for a
PIDFD_THREAD pidfd for a thread-group leader until all subthreads
have been reaped. If a subthread should exec before no exit
notification will be generated until that task exits or it creates
subthreads and repeates the cycle.
This means an exit notification indicates the ability for the father
to reap the child.
* tag 'vfs-6.15-rc1.pidfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (25 commits)
selftests/pidfd: third test for multi-threaded exec polling
selftests/pidfd: second test for multi-threaded exec polling
selftests/pidfd: first test for multi-threaded exec polling
pidfs: improve multi-threaded exec and premature thread-group leader exit polling
pidfs: ensure that PIDFS_INFO_EXIT is available
selftests/pidfd: add seventh PIDFD_INFO_EXIT selftest
selftests/pidfd: add sixth PIDFD_INFO_EXIT selftest
selftests/pidfd: add fifth PIDFD_INFO_EXIT selftest
selftests/pidfd: add fourth PIDFD_INFO_EXIT selftest
selftests/pidfd: add third PIDFD_INFO_EXIT selftest
selftests/pidfd: add second PIDFD_INFO_EXIT selftest
selftests/pidfd: add first PIDFD_INFO_EXIT selftest
selftests/pidfd: expand common pidfd header
pidfs/selftests: ensure correct headers for ioctl handling
selftests/pidfd: fix header inclusion
pidfs: allow to retrieve exit information
pidfs: record exit code and cgroupid at exit
pidfs: use private inode slab cache
pidfs: move setting flags into pidfs_alloc_file()
pidfd: rely on automatic cleanup in __pidfd_prepare()
...
Pull vfs pipe updates from Christian Brauner:
- Introduce struct file_operations pipeanon_fops
- Don't update {a,c,m}time for anonymous pipes to avoid the performance
costs associated with it
- Change pipe_write() to never add a zero-sized buffer
- Limit the slots in pipe_resize_ring()
- Use pipe_buf() to retrieve the pipe buffer everywhere
- Drop an always true check in anon_pipe_write()
- Cache 2 pages instead of 1
- Avoid spurious calls to prepare_to_wait_event() in ___wait_event()
* tag 'vfs-6.15-rc1.pipe' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs/splice: Use pipe_buf() helper to retrieve pipe buffer
fs/pipe: Use pipe_buf() helper to retrieve pipe buffer
kernel/watch_queue: Use pipe_buf() to retrieve the pipe buffer
fs/pipe: Limit the slots in pipe_resize_ring()
wait: avoid spurious calls to prepare_to_wait_event() in ___wait_event()
pipe: cache 2 pages instead of 1
pipe: drop an always true check in anon_pipe_write()
pipe: change pipe_write() to never add a zero-sized buffer
pipe: don't update {a,c,m}time for anonymous pipes
pipe: introduce struct file_operations pipeanon_fops
Pull vfs mount updates from Christian Brauner:
- Mount notifications
The day has come where we finally provide a new api to listen for
mount topology changes outside of /proc/<pid>/mountinfo. A mount
namespace file descriptor can be supplied and registered with
fanotify to listen for mount topology changes.
Currently notifications for mount, umount and moving mounts are
generated. The generated notification record contains the unique
mount id of the mount.
The listmount() and statmount() api can be used to query detailed
information about the mount using the received unique mount id.
This allows userspace to figure out exactly how the mount topology
changed without having to generating diffs of /proc/<pid>/mountinfo
in userspace.
- Support O_PATH file descriptors with FSCONFIG_SET_FD in the new mount
api
- Support detached mounts in overlayfs
Since last cycle we support specifying overlayfs layers via file
descriptors. However, we don't allow detached mounts which means
userspace cannot user file descriptors received via
open_tree(OPEN_TREE_CLONE) and fsmount() directly. They have to
attach them to a mount namespace via move_mount() first.
This is cumbersome and means they have to undo mounts via umount().
Allow them to directly use detached mounts.
- Allow to retrieve idmappings with statmount
Currently it isn't possible to figure out what idmapping has been
attached to an idmapped mount. Add an extension to statmount() which
allows to read the idmapping from the mount.
- Allow creating idmapped mounts from mounts that are already idmapped
So far it isn't possible to allow the creation of idmapped mounts
from already idmapped mounts as this has significant lifetime
implications. Make the creation of idmapped mounts atomic by allow to
pass struct mount_attr together with the open_tree_attr() system call
allowing to solve these issues without complicating VFS lookup in any
way.
The system call has in general the benefit that creating a detached
mount and applying mount attributes to it becomes an atomic operation
for userspace.
- Add a way to query statmount() for supported options
Allow userspace to query which mount information can be retrieved
through statmount().
- Allow superblock owners to force unmount
* tag 'vfs-6.15-rc1.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (21 commits)
umount: Allow superblock owners to force umount
selftests: add tests for mount notification
selinux: add FILE__WATCH_MOUNTNS
samples/vfs: fix printf format string for size_t
fs: allow changing idmappings
fs: add kflags member to struct mount_kattr
fs: add open_tree_attr()
fs: add copy_mount_setattr() helper
fs: add vfs_open_tree() helper
statmount: add a new supported_mask field
samples/vfs: add STATMOUNT_MNT_{G,U}IDMAP
selftests: add tests for using detached mount with overlayfs
samples/vfs: check whether flag was raised
statmount: allow to retrieve idmappings
uidgid: add map_id_range_up()
fs: allow detached mounts in clone_private_mount()
selftests/overlayfs: test specifying layers as O_PATH file descriptors
fs: support O_PATH fds with FSCONFIG_SET_FD
vfs: add notifications for mount attach and detach
fanotify: notify on mount attach and detach
...
Pull misc vfs updates from Christian Brauner:
"Features:
- Add CONFIG_DEBUG_VFS infrastucture:
- Catch invalid modes in open
- Use the new debug macros in inode_set_cached_link()
- Use debug-only asserts around fd allocation and install
- Place f_ref to 3rd cache line in struct file to resolve false
sharing
Cleanups:
- Start using anon_inode_getfile_fmode() helper in various places
- Don't take f_lock during SEEK_CUR if exclusion is guaranteed by
f_pos_lock
- Add unlikely() to kcmp()
- Remove legacy ->remount_fs method from ecryptfs after port to the
new mount api
- Remove invalidate_inodes() in favour of evict_inodes()
- Simplify ep_busy_loopER by removing unused argument
- Avoid mmap sem relocks when coredumping with many missing pages
- Inline getname()
- Inline new_inode_pseudo() and de-staticize alloc_inode()
- Dodge an atomic in putname if ref == 1
- Consistently deref the files table with rcu_dereference_raw()
- Dedup handling of struct filename init and refcounts bumps
- Use wq_has_sleeper() in end_dir_add()
- Drop the lock trip around I_NEW wake up in evict()
- Load the ->i_sb pointer once in inode_sb_list_{add,del}
- Predict not reaching the limit in alloc_empty_file()
- Tidy up do_sys_openat2() with likely/unlikely
- Call inode_sb_list_add() outside of inode hash lock
- Sort out fd allocation vs dup2 race commentary
- Turn page_offset() into a wrapper around folio_pos()
- Remove locking in exportfs around ->get_parent() call
- try_lookup_one_len() does not need any locks in autofs
- Fix return type of several functions from long to int in open
- Fix return type of several functions from long to int in ioctls
Fixes:
- Fix watch queue accounting mismatch"
* tag 'vfs-6.15-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (30 commits)
fs: sort out fd allocation vs dup2 race commentary, take 2
fs: call inode_sb_list_add() outside of inode hash lock
fs: tidy up do_sys_openat2() with likely/unlikely
fs: predict not reaching the limit in alloc_empty_file()
fs: load the ->i_sb pointer once in inode_sb_list_{add,del}
fs: drop the lock trip around I_NEW wake up in evict()
fs: use wq_has_sleeper() in end_dir_add()
VFS/autofs: try_lookup_one_len() does not need any locks
fs: dedup handling of struct filename init and refcounts bumps
fs: consistently deref the files table with rcu_dereference_raw()
exportfs: remove locking around ->get_parent() call.
fs: use debug-only asserts around fd allocation and install
fs: dodge an atomic in putname if ref == 1
vfs: Remove invalidate_inodes()
ecryptfs: remove NULL remount_fs from super_operations
watch_queue: fix pipe accounting mismatch
fs: place f_ref to 3rd cache line in struct file to resolve false sharing
epoll: simplify ep_busy_loop by removing always 0 argument
fs: Turn page_offset() into a wrapper around folio_pos()
kcmp: improve performance adding an unlikely hint to task comparisons
...
CONFIG_TRACE_BRANCH_PROFILING inserts a call to ftrace_likely_update()
for each use of likely() or unlikely(). That breaks noinstr rules if
the affected function is annotated as noinstr.
Disable branch profiling for files with noinstr functions. In addition
to some individual files, this also includes the entire arch/x86
subtree, as well as the kernel/entry, drivers/cpuidle, and drivers/idle
directories, all of which are noinstr-heavy.
Due to the nature of how sched binaries are built by combining multiple
.c files into one, branch profiling is disabled more broadly across the
sched code than would otherwise be needed.
This fixes many warnings like the following:
vmlinux.o: warning: objtool: do_syscall_64+0x40: call to ftrace_likely_update() leaves .noinstr.text section
vmlinux.o: warning: objtool: __rdgsbase_inactive+0x33: call to ftrace_likely_update() leaves .noinstr.text section
vmlinux.o: warning: objtool: handle_bug.isra.0+0x198: call to ftrace_likely_update() leaves .noinstr.text section
...
Reported-by: Ingo Molnar <mingo@kernel.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/fb94fc9303d48a5ed370498f54500cc4c338eb6d.1742586676.git.jpoimboe@kernel.org
Pull scheduler fix from Ingo Molnar:
"Revert a scheduler performance optimization that regressed other
workloads"
* tag 'sched-urgent-2025-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Revert "sched/core: Reduce cost of sched_move_task when config autogroup"
Pull dma-mapping fix from Marek Szyprowski:
- fix missing clear bdr in check_ram_in_range_map() (Baochen Qiang)
* tag 'dma-mapping-6.14-2025-03-21' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
dma-mapping: fix missing clear bdr in check_ram_in_range_map()
Now that the rstat lock is being re-acquired on every CPU iteration in
cgroup_rstat_flush_locked(), having the initially acquire the lock is
unnecessary and unclear.
Inline cgroup_rstat_flush_locked() into cgroup_rstat_flush() and move
the lock/unlock calls to the beginning and ending of the loop body to
make the critical section obvious.
cgroup_rstat_flush_hold/release() do not make much sense with the lock
being dropped and reacquired internally. Since it has no external
callers, remove it and explicitly acquire the lock in
cgroup_base_stat_cputime_show() instead.
This leaves the code with a single flushing function,
cgroup_rstat_flush().
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Signed-off-by: Tejun Heo <tj@kernel.org>
This is another attempt trying to make pidfd polling for multi-threaded
exec and premature thread-group leader exit consistent.
A quick recap of these two cases:
(1) During a multi-threaded exec by a subthread, i.e., non-thread-group
leader thread, all other threads in the thread-group including the
thread-group leader are killed and the struct pid of the
thread-group leader will be taken over by the subthread that called
exec. IOW, two tasks change their TIDs.
(2) A premature thread-group leader exit means that the thread-group
leader exited before all of the other subthreads in the thread-group
have exited.
Both cases lead to inconsistencies for pidfd polling with PIDFD_THREAD.
Any caller that holds a PIDFD_THREAD pidfd to the current thread-group
leader may or may not see an exit notification on the file descriptor
depending on when poll is performed. If the poll is performed before the
exec of the subthread has concluded an exit notification is generated
for the old thread-group leader. If the poll is performed after the exec
of the subthread has concluded no exit notification is generated for the
old thread-group leader.
The correct behavior would be to simply not generate an exit
notification on the struct pid of a subhthread exec because the struct
pid is taken over by the subthread and thus remains alive.
But this is difficult to handle because a thread-group may exit
prematurely as mentioned in (2). In that case an exit notification is
reliably generated but the subthreads may continue to run for an
indeterminate amount of time and thus also may exec at some point.
So far there was no way to distinguish between (1) and (2) internally.
This tiny series tries to address this problem by discarding
PIDFD_THREAD notification on premature thread-group leader exit.
If that works correctly then no exit notifications are generated for a
PIDFD_THREAD pidfd for a thread-group leader until all subthreads have
been reaped. If a subthread should exec aftewards no exit notification
will be generated until that task exits or it creates subthreads and
repeates the cycle.
Co-Developed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20250320-work-pidfs-thread_group-v4-1-da678ce805bf@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
cgroup_rstat_flush_locked() grabs the irq safe cgroup_rstat_lock while
iterating all possible cpus. It only drops the lock if there is
scheduler or spin lock contention. If neither, then interrupts can be
disabled for a long time. On large machines this can disable interrupts
for a long enough time to drop network packets. On 400+ CPU machines
I've seen interrupt disabled for over 40 msec.
Prevent rstat from disabling interrupts while processing all possible
cpus. Instead drop and reacquire cgroup_rstat_lock for each cpu. This
approach was previously discussed in
https://lore.kernel.org/lkml/ZBz%2FV5a7%2F6PZeM7S@slm.duckdns.org/,
though this was in the context of an non-irq rstat spin lock.
Benchmark this change with:
1) a single stat_reader process with 400 threads, each reading a test
memcg's memory.stat repeatedly for 10 seconds.
2) 400 memory hog processes running in the test memcg and repeatedly
charging memory until oom killed. Then they repeat charging and oom
killing.
v6.14-rc6 with CONFIG_IRQSOFF_TRACER with stat_reader and hogs, finds
interrupts are disabled by rstat for 45341 usec:
# => started at: _raw_spin_lock_irq
# => ended at: cgroup_rstat_flush
#
#
# _------=> CPU#
# / _-----=> irqs-off/BH-disabled
# | / _----=> need-resched
# || / _---=> hardirq/softirq
# ||| / _--=> preempt-depth
# |||| / _-=> migrate-disable
# ||||| / delay
# cmd pid |||||| time | caller
# \ / |||||| \ | /
stat_rea-96532 52d.... 0us*: _raw_spin_lock_irq
stat_rea-96532 52d.... 45342us : cgroup_rstat_flush
stat_rea-96532 52d.... 45342us : tracer_hardirqs_on <-cgroup_rstat_flush
stat_rea-96532 52d.... 45343us : <stack trace>
=> memcg1_stat_format
=> memory_stat_format
=> memory_stat_show
=> seq_read_iter
=> vfs_read
=> ksys_read
=> do_syscall_64
=> entry_SYSCALL_64_after_hwframe
With this patch the CONFIG_IRQSOFF_TRACER doesn't find rstat to be the
longest holder. The longest irqs-off holder has irqs disabled for
4142 usec, a huge reduction from previous 45341 usec rstat finding.
Running stat_reader memory.stat reader for 10 seconds:
- without memory hogs: 9.84M accesses => 12.7M accesses
- with memory hogs: 9.46M accesses => 11.1M accesses
The throughput of memory.stat access improves.
The mode of memory.stat access latency after grouping by of 2 buckets:
- without memory hogs: 64 usec => 16 usec
- with memory hogs: 64 usec => 8 usec
The memory.stat latency improves.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Greg Thelen <gthelen@google.com>
Tested-by: Greg Thelen <gthelen@google.com>
Acked-by: Michal Koutný <mkoutny@suse.com>
Reviewed-by: Yosry Ahmed <yosry.ahmed@linux.dev>
Signed-off-by: Tejun Heo <tj@kernel.org>
When we currently create a pidfd we check that the task hasn't been
reaped right before we create the pidfd. But it is of course possible
that by the time we return the pidfd to userspace the task has already
been reaped since we don't check again after having created a dentry for
it.
This was fine until now because that race was meaningless. But now that
we provide PIDFD_INFO_EXIT it is a problem because it is possible that
the kernel returns a reaped pidfd and it depends on the race whether
PIDFD_INFO_EXIT information is available. This depends on if the task
gets reaped before or after a dentry has been attached to struct pid.
Make this consistent and only returned pidfds for reaped tasks if
PIDFD_INFO_EXIT information is available. This is done by performing
another check whether the task has been reaped right after we attached a
dentry to struct pid.
Since pidfs_exit() is called before struct pid's task linkage is removed
the case where the task got reaped but a dentry was already attached to
struct pid and exit information was recorded and published can be
handled correctly. In that case we do return a pidfd for a reaped task
like we would've before.
Link: https://lore.kernel.org/r/20250316-kabel-fehden-66bdb6a83436@brauner
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Pull probes fixes from Masami Hiramatsu:
- Clean up tprobe correctly when module unload
Tracepoint probes do not set TRACEPOINT_STUB on the 'tpoint' pointer
when unloading a module, thus they show as a normal 'fprobe' instead
of 'tprobe' and never come back
- Fix leakage of tprobe module refcount
When a tprobe's target module is loaded, it gets the module's
refcount in the module notifier but forgot to put it after
registering the probe on it.
Fix it by getting the refcount only when registering tprobe.
* tag 'probes-fixes-v6.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: tprobe-events: Fix leakage of module refcount
tracing: tprobe-events: Fix to clean up tprobe correctly when module unload
Rebuilding of root domains accounting information (total_bw) is
currently broken on some cases, e.g. suspend/resume on aarch64. Problem
is that the way we keep track of domain changes and try to add bandwidth
back is convoluted and fragile.
Fix it by simplify things by making sure bandwidth accounting is cleared
and completely restored after root domains changes (after root domains
are again stable).
To be sure we always call dl_rebuild_rd_accounting while holding
cpuset_mutex we also add cpuset_reset_sched_domains() wrapper.
Fixes: 53916d5fd3 ("sched/deadline: Check bandwidth overflow earlier for hotplug")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Co-developed-by: Waiman Long <llong@redhat.com>
Signed-off-by: Waiman Long <llong@redhat.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/Z9MRfeJKJUOyUSto@jlelli-thinkpadt14gen4.remote.csb
Bandwidth checks and updates that work on root domains currently employ
a cookie mechanism for efficiency. This mechanism is very much tied to
when root domains are first created and initialized.
Generalize the cookie mechanism so that it can be used also later at
runtime while updating root domains. Also, additionally guard it with
sched_domains_mutex, since domains need to be stable while updating them
(and it will be required for further dynamic changes).
Fixes: 53916d5fd3 ("sched/deadline: Check bandwidth overflow earlier for hotplug")
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Waiman Long <longman@redhat.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Link: https://lore.kernel.org/r/Z9MQaiXPvEeW_v7x@jlelli-thinkpadt14gen4.remote.csb
The individual architectures often add the preemption model to the begin
of the backtrace. This is the case on X86 or ARM64 for the "die" case
but not for regular warning. With the addition of DYNAMIC_PREEMPT for
PREEMPT_RT we end up with CONFIG_PREEMPT and CONFIG_PREEMPT_RT set
simultaneously. That means that everyone who tried to add that piece of
information gets it wrong for PREEMPT_RT because PREEMPT is checked
first.
Provide a generic function which returns the current scheduling model
considering LAZY preempt and the current state of PREEMPT_DYNAMIC.
The resulting strings are:
┏━━━━━━━━━━━┳━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┓
┃ Model ┃ -RT -DYN ┃ +RT -DYN ┃ -RT +DYN ┃ +RT +DYN ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━┩
│NONE │ NONE │ n/a │ PREEMPT(none) │ n/a │
├───────────┼──────────────┼───────────────────┼────────────────────┼───────────────────┤
│VOLUNTARY │ VOLUNTARY │ n/a │ PREEMPT(voluntary) │ n/a │
├───────────┼──────────────┼───────────────────┼────────────────────┼───────────────────┤
│FULL │ PREEMPT │ PREEMPT_RT │ PREEMPT(full) │ PREEMPT_{RT,full} │
├───────────┼──────────────┼───────────────────┼────────────────────┼───────────────────┤
│LAZY │ PREEMPT_LAZY │ PREEMPT_{RT,LAZY} │ PREEMPT(lazy) │ PREEMPT_{RT,lazy} │
└───────────┴──────────────┴───────────────────┴────────────────────┴───────────────────┘
[ The dynamic building of the string can lead to an empty string if the
function is invoked simultaneously on two CPUs. ]
Co-developed-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Co-developed-by: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Signed-off-by: "Steven Rostedt (Google)" <rostedt@goodmis.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://lore.kernel.org/r/20250314160810.2373416-2-bigeasy@linutronix.de
To save/restore LBR call stack data in system-wide mode, the task_struct
information is required.
Extend the parameters of sched_task() to supply task_struct information.
When schedule in, the LBR call stack data for new task will be restored.
When schedule out, the LBR call stack data for old task will be saved.
Only need to pass the required task_struct information.
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250314172700.438923-4-kan.liang@linux.intel.com
The LBR call stack data has to be saved/restored during context switch
to fix the shorter LBRs call stacks issue in the system-wide mode.
Allocate PMU specific data and attach them to the corresponding
task_struct during LBR call stack monitoring.
When a LBR call stack event is accounted, the perf_ctx_data for the
related tasks will be allocated/attached by attach_perf_ctx_data().
When a LBR call stack event is unaccounted, the perf_ctx_data for
related tasks will be detached/freed by detach_perf_ctx_data().
The LBR call stack event could be a per-task event or a system-wide
event.
- For a per-task event, perf only allocates the perf_ctx_data for the
current task. If the allocation fails, perf will error out.
- For a system-wide event, perf has to allocate the perf_ctx_data for
both the existing tasks and the upcoming tasks.
The allocation for the existing tasks is done in perf_event_alloc().
If any allocation fails, perf will error out.
The allocation for the new tasks will be done in perf_event_fork().
A global reader/writer semaphore, global_ctx_data_rwsem, is added to
address the global race.
- The perf_ctx_data only be freed by the last LBR call stack event.
The number of the per-task events is tracked by refcount of each task.
Since the system-wide events impact all tasks, it's not practical to
go through the whole task list to update the refcount for each
system-wide event. The number of system-wide events is tracked by a
global variable global_ctx_data_ref.
Suggested-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250314172700.438923-3-kan.liang@linux.intel.com
Some PMU specific data has to be saved/restored during context switch,
e.g. LBR call stack data. Currently, the data is saved in event context
structure, but only for per-process event. For system-wide event,
because of missing the LBR call stack data after context switch, LBR
callstacks are always shorter in comparison to per-process mode.
For example,
Per-process mode:
$perf record --call-graph lbr -- taskset -c 0 ./tchain_edit
- 99.90% 99.86% tchain_edit tchain_edit [.] f3
99.86% _start
__libc_start_main
generic_start_main
main
f1
- f2
f3
System-wide mode:
$perf record --call-graph lbr -a -- taskset -c 0 ./tchain_edit
- 99.88% 99.82% tchain_edit tchain_edit [.] f3
- 62.02% main
f1
f2
f3
- 28.83% f1
- f2
f3
- 28.83% f1
- f2
f3
- 8.88% generic_start_main
main
f1
f2
f3
It isn't practical to simply allocate the data for system-wide event in
CPU context structure for all tasks. We have no idea which CPU a task
will be scheduled to. The duplicated LBR data has to be maintained on
every CPU context structure. That's a huge waste. Otherwise, the LBR
data still lost if the task is scheduled to another CPU.
Save the pmu specific data in task_struct. The size of pmu specific data
is 788 bytes for LBR call stack. Usually, the overall amount of threads
doesn't exceed a few thousands. For 10K threads, keeping LBR data would
consume additional ~8MB. The additional space will only be allocated
during LBR call stack monitoring. It will be released when the
monitoring is finished.
Furthermore, moving task_ctx_data from perf_event_context to task_struct
can reduce complexity and make things clearer. E.g. perf doesn't need to
swap task_ctx_data on optimized context switch path.
This patch set is just the first step. There could be other
optimization/extension on top of this patch set. E.g. for cgroup
profiling, perf just needs to save/store the LBR call stack information
for tasks in specific cgroup. That could reduce the additional space.
Also, the LBR call stack can be available for software events, or allow
even debugging use cases, like LBRs on crash later.
Because of the alignment requirement of Intel Arch LBR, the Kmem cache
is used to allocate the PMU specific data. It's required when child task
allocates the space. Save it in struct perf_ctx_data.
The refcount in struct perf_ctx_data is used to track the users of pmu
specific data.
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Link: https://lore.kernel.org/r/20250314172700.438923-1-kan.liang@linux.intel.com
Pinned performance events can enter an error state when they fail to be
scheduled in the context due to a failed constraint or some other conflict
or condition.
In error state these events won't generate any samples anymore and are
silently ignored until they are recovered by PERF_EVENT_IOC_ENABLE,
or the condition can also change so that they can be scheduled in.
Tooling should be allowed to know about the state change, but
currently there's no mechanism to notify tooling when events enter
an error state.
One way to do this is to issue a POLLHUP event to poll(2) to handle this.
Reading events in an error state would return 0 (EOF) and it matches to
the behavior of POLLHUP according to the man page.
Tooling should remove the fd of the event from pollfd after getting
POLLHUP, otherwise it'll be returned repeatedly.
[ mingo: Clarified the changelog ]
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20250317061745.1777584-1-namhyung@kernel.org
Pull tracing fix from Steven Rostedt:
"Fix ref count of trace_array in error path of histogram file open
Tracing instances have a ref count to keep them around while files
within their directories are open. This prevents them from being
deleted while they are used.
The histogram code had some files that needed to take the ref count
and that was added, but the error paths did not decrement the ref
counts. This caused the instances from ever being removed if a
histogram file failed to open due to some error"
* tag 'trace-v6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Correct the refcount if the hist/hist_debug file fails to open
