user/sven/linux.git/kernel/exit.c, branch next/HEAD

Merge branch 'fs-next' of linux-next

2026-04-09T13:09:24Z

exit: kill unnecessary thread_group_leader() checks in exit_notify() and do_notify_parent()

2026-03-28T04:19:34Z

thread_group_empty(tsk) is only possible if tsk is a group leader, and thread_group_empty() already does the thread_group_leader() check. So it makes no sense to check "thread_group_leader() && thread_group_empty()"; thread_group_empty() alone is enough. Link: https://lkml.kernel.org/r/aZsfeegKZPZZszJh@redhat.com Signed-off-by: Oleg Nesterov Cc: Christian Brauner Cc: Mateusz Guzik Cc: Kees Cook Cc; Deepanshu Kartikey Signed-off-by: Andrew Morton

pid_namespace: avoid optimization of accesses to ->child_reaper

2026-03-20T13:44:25Z

To avoid potential problems related to cpu/compiler optimizations around ->child_reaper, let's use WRITE_ONCE (additional to task_list lock) everywhere we write it and use READ_ONCE where we read it without explicit lock. Note: It also pairs with existing READ_ONCE with no lock in nsfs_fh_to_dentry(). Also let's add ASSERT_EXCLUSIVE_WRITER before write to identify to KCSAN that we don't expect any concurrent ->child_reaper modifications, and those must be detected. -- Suggested-by: Oleg Nesterov Acked-by: Oleg Nesterov Signed-off-by: Pavel Tikhomirov Link: https://patch.msgid.link/20260318122157.280595-2-ptikhomirov@virtuozzo.com v3: Split from main commit. Add ASSERT_EXCLUSIVE_WRITER. v5: Add one more READ_ONCE for access without lock in free_pid(). Signed-off-by: Christian Brauner

kthread: consolidate kthread exit paths to prevent use-after-free

2026-02-26T09:45:49Z

Guillaume reported crashes via corrupted RCU callback function pointers during KUnit testing. The crash was traced back to the pidfs rhashtable conversion which replaced the 24-byte rb_node with an 8-byte rhash_head in struct pid, shrinking it from 160 to 144 bytes. struct kthread (without CONFIG_BLK_CGROUP) is also 144 bytes. With CONFIG_SLAB_MERGE_DEFAULT and SLAB_HWCACHE_ALIGN both round up to 192 bytes and share the same slab cache. struct pid.rcu.func and struct kthread.affinity_node both sit at offset 0x78. When a kthread exits via make_task_dead() it bypasses kthread_exit() and misses the affinity_node cleanup. free_kthread_struct() frees the memory while the node is still linked into the global kthread_affinity_list. A subsequent list_del() by another kthread writes through dangling list pointers into the freed and reused memory, corrupting the pid's rcu.func pointer. Instead of patching free_kthread_struct() to handle the missed cleanup, consolidate all kthread exit paths. Turn kthread_exit() into a macro that calls do_exit() and add kthread_do_exit() which is called from do_exit() for any task with PF_KTHREAD set. This guarantees that kthread-specific cleanup always happens regardless of the exit path - make_task_dead(), direct do_exit(), or kthread_exit(). Replace __to_kthread() with a new tsk_is_kthread() accessor in the public header. Export do_exit() since module code using the kthread_exit() macro now needs it directly. Reported-by: Guillaume Tucker Tested-by: Guillaume Tucker Tested-by: Mark Brown Tested-by: David Gow Cc: Link: https://lore.kernel.org/all/20260224-mittlerweile-besessen-2738831ae7f6@brauner Co-developed-by: Linus Torvalds Fixes: 4d13f4304fa4 ("kthread: Implement preferred affinity") Signed-off-by: Linus Torvalds Signed-off-by: Christian Brauner

Merge tag 'mm-nonmm-stable-2025-12-06-11-14' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-12-06T22:01:20Z

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 ...

Merge tag 'cgroup-for-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2025-12-03T21:04:07Z

Pull cgroup updates from Tejun Heo: - Defer task cgroup unlink until after the dying task's final context switch so that controllers see the cgroup properly populated until the task is truly gone - cpuset cleanups and simplifications. Enforce that domain isolated CPUs stay in root or isolated partitions and fail if isolated+nohz_full would leave no housekeeping CPU. Fix sched/deadline root domain handling during CPU hot-unplug and race for tasks in attaching cpusets - Misc fixes including memory reclaim protection documentation and selftest KTAP conformance * tag 'cgroup-for-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (21 commits) cpuset: Treat cpusets in attaching as populated sched/deadline: Walk up cpuset hierarchy to decide root domain when hot-unplug cgroup/cpuset: Introduce cpuset_cpus_allowed_locked() docs: cgroup: No special handling of unpopulated memcgs docs: cgroup: Note about sibling relative reclaim protection docs: cgroup: Explain reclaim protection target selftests/cgroup: conform test to KTAP format output cpuset: remove need_rebuild_sched_domains cpuset: remove global remote_children list cpuset: simplify node setting on error cgroup: include missing header for struct irq_work cgroup: Fix sleeping from invalid context warning on PREEMPT_RT cgroup/cpuset: Globally track isolated_cpus update cgroup/cpuset: Ensure domain isolated CPUs stay in root or isolated partition cgroup/cpuset: Move up prstate_housekeeping_conflict() helper cgroup/cpuset: Fail if isolated and nohz_full don't leave any housekeeping cgroup/cpuset: Rename update_unbound_workqueue_cpumask() to update_isolation_cpumasks() cgroup: Defer task cgroup unlink until after the task is done switching out cgroup: Move dying_tasks cleanup from cgroup_task_release() to cgroup_task_free() cgroup: Rename cgroup lifecycle hooks to cgroup_task_*() ...

Merge tag 'core-rseq-2025-11-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-12-02T16:48:53Z

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 ...

Merge tag 'perf-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2025-12-02T04:42:01Z

Pull performance events updates from Ingo Molnar: "Callchain support: - Add support for deferred user-space stack unwinding for perf, enabled on x86. (Peter Zijlstra, Steven Rostedt) - unwind_user/x86: Enable frame pointer unwinding on x86 (Josh Poimboeuf) x86 PMU support and infrastructure: - x86/insn: Simplify for_each_insn_prefix() (Peter Zijlstra) - x86/insn,uprobes,alternative: Unify insn_is_nop() (Peter Zijlstra) Intel PMU driver: - Large series to prepare for and implement architectural PEBS support for Intel platforms such as Clearwater Forest (CWF) and Panther Lake (PTL). (Dapeng Mi, Kan Liang) - Check dynamic constraints (Kan Liang) - Optimize PEBS extended config (Peter Zijlstra) - cstates: - Remove PC3 support from LunarLake (Zhang Rui) - Add Pantherlake support (Zhang Rui) - Clearwater Forest support (Zide Chen) AMD PMU driver: - x86/amd: Check event before enable to avoid GPF (George Kennedy) Fixes and cleanups: - task_work: Fix NMI race condition (Peter Zijlstra) - perf/x86: Fix NULL event access and potential PEBS record loss (Dapeng Mi) - Misc other fixes and cleanups (Dapeng Mi, Ingo Molnar, Peter Zijlstra)" * tag 'perf-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (38 commits) perf/x86/intel: Fix and clean up intel_pmu_drain_arch_pebs() type use perf/x86/intel: Optimize PEBS extended config perf/x86/intel: Check PEBS dyn_constraints perf/x86/intel: Add a check for dynamic constraints perf/x86/intel: Add counter group support for arch-PEBS perf/x86/intel: Setup PEBS data configuration and enable legacy groups perf/x86/intel: Update dyn_constraint base on PEBS event precise level perf/x86/intel: Allocate arch-PEBS buffer and initialize PEBS_BASE MSR perf/x86/intel: Process arch-PEBS records or record fragments perf/x86/intel/ds: Factor out PEBS group processing code to functions perf/x86/intel/ds: Factor out PEBS record processing code to functions perf/x86/intel: Initialize architectural PEBS perf/x86/intel: Correct large PEBS flag check perf/x86/intel: Replace x86_pmu.drain_pebs calling with static call perf/x86: Fix NULL event access and potential PEBS record loss perf/x86: Remove redundant is_x86_event() prototype entry,unwind/deferred: Fix unwind_reset_info() placement unwind_user/x86: Fix arch=um build perf: Support deferred user unwind unwind_user/x86: Teach FP unwind about start of function ...

signal: Move MMCID exit out of sighand lock

2025-11-25T18:45:40Z

There is no need anymore to keep this under sighand lock as the current code and the upcoming replacement are not depending on the exit state of a task anymore. That allows to use a mutex in the exit path. Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Reviewed-by: Mathieu Desnoyers Link: https://patch.msgid.link/20251119172549.706439391@linutronix.de

release_task: kill unnecessary rcu_read_lock() around dec_rlimit_ucounts()

2025-11-12T18:00:17Z

rcu_read_lock() was added to shut RCU-lockdep up when this code used __task_cred()->rcu_dereference(), but after the commit 21d1c5e386bc ("Reimplement RLIMIT_NPROC on top of ucounts") it is no longer needed: task_ucounts()->task_cred_xxx() takes rcu_read_lock() itself. NOTE: task_ucounts() returns the pointer to another rcu-protected data, struct ucounts. So it should either be used when task->real_cred and thus task->real_cred->ucounts is stable (release_task, copy_process, copy_creds), or it should be called under rcu_read_lock(). In both cases it is pointless to take rcu_read_lock() to read the cred->ucounts pointer. Link: https://lkml.kernel.org/r/20251026143140.GA22463@redhat.com Signed-off-by: Oleg Nesterov Acked-by: Alexey Gladkov Cc: David Howells Cc: Mateusz Guzik Cc: "Paul E . McKenney" Cc: Kees Cook Signed-off-by: Andrew Morton