<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/kernel/fork.c, branch v7.3-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'mm-nonmm-stable-2026-08-22-16-57' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm</title>
<updated>2026-08-23T15:07:11+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-08-23T15:07:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e5f92606156a6a823992294d214c285b49cd72e9'/>
<id>e5f92606156a6a823992294d214c285b49cd72e9</id>
<content type='text'>
Pull non-MM updates from Andrew Morton:

 - "ocfs2/dlm: bound peer-controlled lengths in the o2dlm" (Bryam
   Vargas)

   Validate and bound all input lengths and count fields in the o2dlm
   migration and recovery receive handlers to prevent memory corruption
   and kernel panics from malformed cluster messages

 - "ocfs2: validate xattr entry bounds" (Cen Zhang)

   Validate OCFS2 extended attribute entry name and value bounds during
   metadata reads to prevent out-of-range memory accesses during
   retrieval or listing operations.

 - "taskstats: fix cgroupstats invalid fd handling and add selftests"
   (Yiyang Chen)

   Return -EBADF when cgroupstats receives an invalid file descriptor to
   prevent caller hangs and misleading success ACKs. Add a kselftest to
   validate valid cgroup v1 queries and verify proper error handling
   across different Netlink flag combinations.

 - "misc lib/raid/ improvements v2" (Christoph Hellwig)

   Improve benchmark-based algorithm selection for the XOR and RAID6
   libraries, add KUnit benchmark tests, and cleanup minor
   implementation details.

 - "ocfs2: cluster: o2hb_region_pin() fixes" (Joseph Qi)

   Fix sleeping-in-atomic, lock order inversion and error-path cleanup
   bugs in o2hb_region_pin() by releasing o2hb_live_lock across sleeping
   configfs_depend_item() calls and using unlocked variants from
   callback context. Ensure failed pin attempts properly decrement user
   counts and unpin partially initialized heartbeat regions to prevent
   memory leaks and unprotected states.

 - "lib/ucs2_string.c: fix out-of-bounds read in ucs2_strnlen()"
   (Vincent Mailhol)

   Fix an off-by-one which could cause an out-of-bounds read.

 - "ocfs2: harden heartbeat teardown races" (Cen Zhang)

   Fix two OCFS2 heartbeat/o2net teardown races found by KASAN.

 - "taskstats: tidy up the cpumask command path" *Bradley Morgan)

   make two small cleanups in kernel/taskstats.c.

 - "ocfs2: validate active orphan slots during inode read" (ZhengYuan
   Huang)

   Validate active ordinary and append-DIO orphan slots read from OCFS2
   dinodes at the metadata boundary to prevent corrupted slot indices
   from causing out-of-bounds array accesses.

 - "ocfs2: bound-check both readdir re-validation scans" (Zhan Xusheng)

   Enforce strict boundary checks on directory entry record lengths and
   offset calculations during OCFS2 directory re-scans to prevent
   out-of-bounds memory reads and directory position corruption.

* tag 'mm-nonmm-stable-2026-08-22-16-57' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (95 commits)
  mailmap: fix bouncing address for Taniya Das
  ocfs2: bound-check dir entries in the inline-data re-validation scan
  ocfs2: bound-check dir entries in the readdir re-validation scan
  squashfs: avoid thundering-herd cache wakeups
  prctl: fix PR_SET_MM_AUXV losing the forced AT_NULL terminator
  mailmap: update email address for Linfeng Sun
  lib/interval_tree: fix allocation warning messages
  checkpatch: add NOKPROBE_SYMBOL to the whitelist of lines that can occur immediately after functions
  Squashfs: check block offset is not negative
  signal: factor out the kernel reserved si_code check
  ocfs2: fix readdir position truncation on 32-bit kernels
  ocfs2: fix cached cluster count after suballocator reclaim
  ocfs2: fix circular locking dependency in ocfs2_init_acl()
  ocfs2: validate DIO orphan slot during inode read
  ocfs2: validate orphan slot during inode read
  selftests/prctl: fix non-anonymous VMA mapping in set-anon-vma-name test
  MAINTAINERS: add IRC and patchwork for LTP
  include/linux/list.h: mark list_add and __list_add as __always_inline
  tools/mm: prevent page_owner_sort from truncating input
  hung_task: update DETECT_HUNG_TASK_BLOCKER Kconfig help
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull non-MM updates from Andrew Morton:

 - "ocfs2/dlm: bound peer-controlled lengths in the o2dlm" (Bryam
   Vargas)

   Validate and bound all input lengths and count fields in the o2dlm
   migration and recovery receive handlers to prevent memory corruption
   and kernel panics from malformed cluster messages

 - "ocfs2: validate xattr entry bounds" (Cen Zhang)

   Validate OCFS2 extended attribute entry name and value bounds during
   metadata reads to prevent out-of-range memory accesses during
   retrieval or listing operations.

 - "taskstats: fix cgroupstats invalid fd handling and add selftests"
   (Yiyang Chen)

   Return -EBADF when cgroupstats receives an invalid file descriptor to
   prevent caller hangs and misleading success ACKs. Add a kselftest to
   validate valid cgroup v1 queries and verify proper error handling
   across different Netlink flag combinations.

 - "misc lib/raid/ improvements v2" (Christoph Hellwig)

   Improve benchmark-based algorithm selection for the XOR and RAID6
   libraries, add KUnit benchmark tests, and cleanup minor
   implementation details.

 - "ocfs2: cluster: o2hb_region_pin() fixes" (Joseph Qi)

   Fix sleeping-in-atomic, lock order inversion and error-path cleanup
   bugs in o2hb_region_pin() by releasing o2hb_live_lock across sleeping
   configfs_depend_item() calls and using unlocked variants from
   callback context. Ensure failed pin attempts properly decrement user
   counts and unpin partially initialized heartbeat regions to prevent
   memory leaks and unprotected states.

 - "lib/ucs2_string.c: fix out-of-bounds read in ucs2_strnlen()"
   (Vincent Mailhol)

   Fix an off-by-one which could cause an out-of-bounds read.

 - "ocfs2: harden heartbeat teardown races" (Cen Zhang)

   Fix two OCFS2 heartbeat/o2net teardown races found by KASAN.

 - "taskstats: tidy up the cpumask command path" *Bradley Morgan)

   make two small cleanups in kernel/taskstats.c.

 - "ocfs2: validate active orphan slots during inode read" (ZhengYuan
   Huang)

   Validate active ordinary and append-DIO orphan slots read from OCFS2
   dinodes at the metadata boundary to prevent corrupted slot indices
   from causing out-of-bounds array accesses.

 - "ocfs2: bound-check both readdir re-validation scans" (Zhan Xusheng)

   Enforce strict boundary checks on directory entry record lengths and
   offset calculations during OCFS2 directory re-scans to prevent
   out-of-bounds memory reads and directory position corruption.

* tag 'mm-nonmm-stable-2026-08-22-16-57' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (95 commits)
  mailmap: fix bouncing address for Taniya Das
  ocfs2: bound-check dir entries in the inline-data re-validation scan
  ocfs2: bound-check dir entries in the readdir re-validation scan
  squashfs: avoid thundering-herd cache wakeups
  prctl: fix PR_SET_MM_AUXV losing the forced AT_NULL terminator
  mailmap: update email address for Linfeng Sun
  lib/interval_tree: fix allocation warning messages
  checkpatch: add NOKPROBE_SYMBOL to the whitelist of lines that can occur immediately after functions
  Squashfs: check block offset is not negative
  signal: factor out the kernel reserved si_code check
  ocfs2: fix readdir position truncation on 32-bit kernels
  ocfs2: fix cached cluster count after suballocator reclaim
  ocfs2: fix circular locking dependency in ocfs2_init_acl()
  ocfs2: validate DIO orphan slot during inode read
  ocfs2: validate orphan slot during inode read
  selftests/prctl: fix non-anonymous VMA mapping in set-anon-vma-name test
  MAINTAINERS: add IRC and patchwork for LTP
  include/linux/list.h: mark list_add and __list_add as __always_inline
  tools/mm: prevent page_owner_sort from truncating input
  hung_task: update DETECT_HUNG_TASK_BLOCKER Kconfig help
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'locking-urgent-2026-08-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2026-08-22T23:29:20+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-08-22T23:29:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=0d78592583949b531318b51763ade7ff536ba9bc'/>
<id>0d78592583949b531318b51763ade7ff536ba9bc</id>
<content type='text'>
Pull futex fixes from Ingo Molnar:

 - Enforce that the private futex owner shares the mm when attaching
   (Kyle Zeng, Thomas Gleixner)

 - Fix race on the initial mm-&gt;futex.phash.ref allocation (Hyunwoo Kim)

 - Fix might_sleep() warning in futex_pivot_pending() (Peter Zijlstra)

* tag 'locking-urgent-2026-08-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Fix might_sleep() warning in futex_pivot_pending()
  futex: Fix race on the initial mm-&gt;futex.phash.ref allocation
  futex: Clean up the redundant exit/exec functions
  futex/pi: Plug private futex exec() race
  futex: Sanitize and document task_struct::futex::state transitions
  futex/pi: Reject cross-mm private futex owners
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull futex fixes from Ingo Molnar:

 - Enforce that the private futex owner shares the mm when attaching
   (Kyle Zeng, Thomas Gleixner)

 - Fix race on the initial mm-&gt;futex.phash.ref allocation (Hyunwoo Kim)

 - Fix might_sleep() warning in futex_pivot_pending() (Peter Zijlstra)

* tag 'locking-urgent-2026-08-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Fix might_sleep() warning in futex_pivot_pending()
  futex: Fix race on the initial mm-&gt;futex.phash.ref allocation
  futex: Clean up the redundant exit/exec functions
  futex/pi: Plug private futex exec() race
  futex: Sanitize and document task_struct::futex::state transitions
  futex/pi: Reject cross-mm private futex owners
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'smp-core-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2026-08-18T22:29:53+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-08-18T22:29:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=0dd1a54f44348d9cf6bae57a2b5cb0b53826a2c7'/>
<id>0dd1a54f44348d9cf6bae57a2b5cb0b53826a2c7</id>
<content type='text'>
Pull SMP core updates from Thomas Gleixner:

 - Reduce the preemption disabled sections in smp_call_function*().

   The various smp call functions keep preemption disabled accross the
   full operation which includes the wait for completion. Especially the
   latter can take some time when one of the target CPUs is not
   immediately responding to the IPI, which can result in large latency
   spikes.

   To improve this provide a per task CPU mask to track the CPUs to wait
   for. That makes the information required for the wait task local and
   therefore allows to reenable preemption before the wait.

   While this comes with moderate extra memory cost this reduces SMP
   function call induced latency measured in a fleet for high priority
   tasks from ~17ms to ~1.5ms (~90%).

 - Reduce the overhead of the CSD debug code by replacing the heavy
   memory barriers with smp_store_release()/acquire()

 - Remove obsolute unused hotplug states

* tag 'smp-core-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  scftorture: Remove preempt_disable() in scftorture_invoke_one()
  smp: Remove preempt_disable() from on_each_cpu_cond_mask()
  smp: Remove preempt_disable() from smp_call_function()
  smp: Enable preemption early in smp_call_function_many_cond()
  smp: Alloc percpu csd data in smpcfd_prepare_cpu() only once
  smp: Use task-local IPI cpumask in smp_call_function_many_cond()
  smp: Refactor remote CPU selection in smp_call_function_any()
  smp: Enable preemption early in smp_call_function_single()
  smp: Disable preemption explicitly in __csd_lock_wait()
  cpu/hotplug: Remove CPUHP_AP_ARM_CORESIGHT_CTI_STARTING
  smp: Use release stores for csd_lock_record() state
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull SMP core updates from Thomas Gleixner:

 - Reduce the preemption disabled sections in smp_call_function*().

   The various smp call functions keep preemption disabled accross the
   full operation which includes the wait for completion. Especially the
   latter can take some time when one of the target CPUs is not
   immediately responding to the IPI, which can result in large latency
   spikes.

   To improve this provide a per task CPU mask to track the CPUs to wait
   for. That makes the information required for the wait task local and
   therefore allows to reenable preemption before the wait.

   While this comes with moderate extra memory cost this reduces SMP
   function call induced latency measured in a fleet for high priority
   tasks from ~17ms to ~1.5ms (~90%).

 - Reduce the overhead of the CSD debug code by replacing the heavy
   memory barriers with smp_store_release()/acquire()

 - Remove obsolute unused hotplug states

* tag 'smp-core-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  scftorture: Remove preempt_disable() in scftorture_invoke_one()
  smp: Remove preempt_disable() from on_each_cpu_cond_mask()
  smp: Remove preempt_disable() from smp_call_function()
  smp: Enable preemption early in smp_call_function_many_cond()
  smp: Alloc percpu csd data in smpcfd_prepare_cpu() only once
  smp: Use task-local IPI cpumask in smp_call_function_many_cond()
  smp: Refactor remote CPU selection in smp_call_function_any()
  smp: Enable preemption early in smp_call_function_single()
  smp: Disable preemption explicitly in __csd_lock_wait()
  cpu/hotplug: Remove CPUHP_AP_ARM_CORESIGHT_CTI_STARTING
  smp: Use release stores for csd_lock_record() state
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'perf-core-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</title>
<updated>2026-08-18T19:31:07+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-08-18T19:31:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8915457146a11d20a6c0786396376afda65eec40'/>
<id>8915457146a11d20a6c0786396376afda65eec40</id>
<content type='text'>
Pull performance events updates from Ingo Molnar:
 "uprobes updates:

   - Fix a category of bugs with optimized uprobes that can clobber the
     redzone area with call instruction storing return address on stack
     where user code may keep temporary data without adjusting RSP.

     Fix this by moving the optimized uprobes on top of 10-bytes NOP
     instruction, so we can squeeze another instruction to escape the
     redzone area before doing the call (Jiri Olsa, Andrii Nakryiko)

   - Switch uretprobes_srcu to SRCU-fast-updown, to improve performance
     (Puranjay Mohan)

  Intel CPU PMU driver updates:

   - Optimize ACR handling in match_prev_assignment() (Dapeng Mi)

   - Fix various PMU driver bugs and data leaks (Dapeng Mi)

   - Fix Intel PT stop/start with no update (Adrian Hunter)

  Intel uncore PMU driver updates:

   - Fix various uncore PMU setup robustness bugs (Zide Chen)

  AMD uncore PMU driver updates:

   - Add group validation (Sandipan Das)

  .. and misc fixes and updates by Dapeng Mi, Randy Dunlap and Zide Chen"

* tag 'perf-core-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (42 commits)
  perf/x86: Optimize ACR handling in match_prev_assignment()
  perf/x86/intel: Fix intel_cap handling on hybrid PMUs
  perf/x86: Remove stale fixed counter helper and fix hybrid PMU access
  perf/x86/intel: Unwind cpuc state if PEBS buffer setup fails
  perf/x86: Guard intel_pmu_cpu_dead() against invalid hybrid PMU casts
  perf/x86: Free hybrid state on PMU init failure
  perf/x86: Unregister PMI handler on PMU init failure
  perf/x86/intel/pt: Fix stop/start with no update
  perf/x86/intel/pt: Use bitwise access for PERF_HES_STOPPED
  perf/x86/intel/pt: Factor out pt_config_enable()
  uprobes: Switch uretprobes_srcu to SRCU-fast-updown
  srcu: Add lock guard for srcu_fast_updown flavor
  perf/x86/intel/pt: Drop kernel-doc for deleted struct members
  perf/x86/amd/uncore: Add group validation
  selftests/bpf: Add tests for forked/cloned optimized uprobes
  selftests/bpf: Add tests for uprobe nop10 red zone clobbering
  selftests/bpf: Add reattach tests for uprobe syscall
  selftests/bpf: Change uprobe/usdt trigger bench code to use nop10
  selftests/bpf: Change uprobe syscall tests to use nop10
  selftests/bpf: Emit nop,nop10 instructions combo for x86_64 arch
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull performance events updates from Ingo Molnar:
 "uprobes updates:

   - Fix a category of bugs with optimized uprobes that can clobber the
     redzone area with call instruction storing return address on stack
     where user code may keep temporary data without adjusting RSP.

     Fix this by moving the optimized uprobes on top of 10-bytes NOP
     instruction, so we can squeeze another instruction to escape the
     redzone area before doing the call (Jiri Olsa, Andrii Nakryiko)

   - Switch uretprobes_srcu to SRCU-fast-updown, to improve performance
     (Puranjay Mohan)

  Intel CPU PMU driver updates:

   - Optimize ACR handling in match_prev_assignment() (Dapeng Mi)

   - Fix various PMU driver bugs and data leaks (Dapeng Mi)

   - Fix Intel PT stop/start with no update (Adrian Hunter)

  Intel uncore PMU driver updates:

   - Fix various uncore PMU setup robustness bugs (Zide Chen)

  AMD uncore PMU driver updates:

   - Add group validation (Sandipan Das)

  .. and misc fixes and updates by Dapeng Mi, Randy Dunlap and Zide Chen"

* tag 'perf-core-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (42 commits)
  perf/x86: Optimize ACR handling in match_prev_assignment()
  perf/x86/intel: Fix intel_cap handling on hybrid PMUs
  perf/x86: Remove stale fixed counter helper and fix hybrid PMU access
  perf/x86/intel: Unwind cpuc state if PEBS buffer setup fails
  perf/x86: Guard intel_pmu_cpu_dead() against invalid hybrid PMU casts
  perf/x86: Free hybrid state on PMU init failure
  perf/x86: Unregister PMI handler on PMU init failure
  perf/x86/intel/pt: Fix stop/start with no update
  perf/x86/intel/pt: Use bitwise access for PERF_HES_STOPPED
  perf/x86/intel/pt: Factor out pt_config_enable()
  uprobes: Switch uretprobes_srcu to SRCU-fast-updown
  srcu: Add lock guard for srcu_fast_updown flavor
  perf/x86/intel/pt: Drop kernel-doc for deleted struct members
  perf/x86/amd/uncore: Add group validation
  selftests/bpf: Add tests for forked/cloned optimized uprobes
  selftests/bpf: Add tests for uprobe nop10 red zone clobbering
  selftests/bpf: Add reattach tests for uprobe syscall
  selftests/bpf: Change uprobe/usdt trigger bench code to use nop10
  selftests/bpf: Change uprobe syscall tests to use nop10
  selftests/bpf: Emit nop,nop10 instructions combo for x86_64 arch
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'vfs-7.3-rc1.kthread' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs</title>
<updated>2026-08-17T18:35:12+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2026-08-17T18:35:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=fff0150b0299f834fe2c335ce0eb5c68bb414cbd'/>
<id>fff0150b0299f834fe2c335ce0eb5c68bb414cbd</id>
<content type='text'>
Pull kthread vfs updates from Christian Brauner:
 "This stops kernel threads from sharing filesystem state with
  userspace. This work is about 3 cycles old and has been in -next
  for about that time.

  When the kernel boots init_task creates PID 1 and then kthreadd. From
  that point every kthread and PID 1 share the same fs_struct. That is
  why pivot_root() has to rewrite the fs_struct of all kthreads. The
  rewriting exists so that kthreads can use init's filesystem state when
  they want to. It also means userspace can move the ground out from
  under the kernel.

  PID 1 now gets a completely separate fs_struct. All kthreads are
  anchored in a private SB_KERNMOUNT instance of nullfs that cannot be
  mounted on and cannot be used to follow other mounts. Userspace init
  can no longer affect kthread filesystem state and kthreads can no
  longer affect userspace fs state without explicit opting in to that.

  Path lookup from a kthread now fails by default. It makes it
  deliberately hard to offload security sensitive operations into init's
  filesystem state from a kthread.

  Places that legitimately need to look something up there opt in
  through the new scoped_with_init_fs() which temporarily overrides the
  caller's fs_struct with init's. usermodehelpers remain the only kernel
  tasks that genuinely share init's filesystem state, since they execute
  random binaries in the root filesystem (excellent...).

  The visible result is that /proc/2/root is a nullfs with an empty
  mountinfo while /proc/1/root is the real root"

* tag 'vfs-7.3-rc1.kthread' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (26 commits)
  initramfs_test: use test init/exit hooks to override init fs
  fs: stop rewriting paths for PF_EXITING | PF_DUMPCORE
  fs: stop rewriting kthread fs structs
  fs: start all kthreads in nullfs
  nullfs: make nullfs multi-instance
  devtmpfs: create private mount namespace
  fs: add umh argument to struct kernel_clone_args
  fs: stop sharing fs_struct between init_task and pid 1
  af_unix: use scoped_with_init_fs() for coredump socket lookup
  initramfs: use scoped_with_init_fs() for rootfs unpacking
  pnfs/blocklayout: use scoped_with_init_fs() for SCSI device lookup
  ksmbd: use scoped_with_init_fs() for VFS path operations
  ksmbd: use scoped_with_init_fs() for filesystem info path lookup
  ksmbd: use scoped_with_init_fs() for share path resolution
  fs: use scoped_with_init_fs() for kernel_read_file_from_path_initns()
  coredump: use scoped_with_init_fs() for coredump path resolution
  btrfs: use scoped_with_init_fs() for update_dev_time()
  scsi: target: use scoped_with_init_fs() for APTPL metadata
  scsi: target: use scoped_with_init_fs() for ALUA metadata
  crypto: ccp: use scoped_with_init_fs() for SEV file access
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull kthread vfs updates from Christian Brauner:
 "This stops kernel threads from sharing filesystem state with
  userspace. This work is about 3 cycles old and has been in -next
  for about that time.

  When the kernel boots init_task creates PID 1 and then kthreadd. From
  that point every kthread and PID 1 share the same fs_struct. That is
  why pivot_root() has to rewrite the fs_struct of all kthreads. The
  rewriting exists so that kthreads can use init's filesystem state when
  they want to. It also means userspace can move the ground out from
  under the kernel.

  PID 1 now gets a completely separate fs_struct. All kthreads are
  anchored in a private SB_KERNMOUNT instance of nullfs that cannot be
  mounted on and cannot be used to follow other mounts. Userspace init
  can no longer affect kthread filesystem state and kthreads can no
  longer affect userspace fs state without explicit opting in to that.

  Path lookup from a kthread now fails by default. It makes it
  deliberately hard to offload security sensitive operations into init's
  filesystem state from a kthread.

  Places that legitimately need to look something up there opt in
  through the new scoped_with_init_fs() which temporarily overrides the
  caller's fs_struct with init's. usermodehelpers remain the only kernel
  tasks that genuinely share init's filesystem state, since they execute
  random binaries in the root filesystem (excellent...).

  The visible result is that /proc/2/root is a nullfs with an empty
  mountinfo while /proc/1/root is the real root"

* tag 'vfs-7.3-rc1.kthread' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (26 commits)
  initramfs_test: use test init/exit hooks to override init fs
  fs: stop rewriting paths for PF_EXITING | PF_DUMPCORE
  fs: stop rewriting kthread fs structs
  fs: start all kthreads in nullfs
  nullfs: make nullfs multi-instance
  devtmpfs: create private mount namespace
  fs: add umh argument to struct kernel_clone_args
  fs: stop sharing fs_struct between init_task and pid 1
  af_unix: use scoped_with_init_fs() for coredump socket lookup
  initramfs: use scoped_with_init_fs() for rootfs unpacking
  pnfs/blocklayout: use scoped_with_init_fs() for SCSI device lookup
  ksmbd: use scoped_with_init_fs() for VFS path operations
  ksmbd: use scoped_with_init_fs() for filesystem info path lookup
  ksmbd: use scoped_with_init_fs() for share path resolution
  fs: use scoped_with_init_fs() for kernel_read_file_from_path_initns()
  coredump: use scoped_with_init_fs() for coredump path resolution
  btrfs: use scoped_with_init_fs() for update_dev_time()
  scsi: target: use scoped_with_init_fs() for APTPL metadata
  scsi: target: use scoped_with_init_fs() for ALUA metadata
  crypto: ccp: use scoped_with_init_fs() for SEV file access
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>futex: Clean up the redundant exit/exec functions</title>
<updated>2026-08-15T22:16:32+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@kernel.org</email>
</author>
<published>2026-08-07T15:07:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=221b62e97811845340c888993ae049467399d2b5'/>
<id>221b62e97811845340c888993ae049467399d2b5</id>
<content type='text'>
futex_exit_release() and futex_exec_release() are identical now. That means
also exit_mm_release() and exec_mm_release() are identical.

Consolidate the whole lot and remove the redundant copies.

Signed-off-by: Thomas Gleixner &lt;tglx@kernel.org&gt;
Reviewed-by: Kyle Zeng &lt;kylebot@openai.com&gt;
Acked-by: Peter Zijlstra &lt;peterz@infradead.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
futex_exit_release() and futex_exec_release() are identical now. That means
also exit_mm_release() and exec_mm_release() are identical.

Consolidate the whole lot and remove the redundant copies.

Signed-off-by: Thomas Gleixner &lt;tglx@kernel.org&gt;
Reviewed-by: Kyle Zeng &lt;kylebot@openai.com&gt;
Acked-by: Peter Zijlstra &lt;peterz@infradead.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>kernel/fork: declare max_threads __read_mostly</title>
<updated>2026-08-04T04:10:11+00:00</updated>
<author>
<name>JianChunfu</name>
<email>jansef.jian@hj-micro.com</email>
</author>
<published>2026-07-07T09:23:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=1db1573bc59f7c91fa2867e4cbea73494d5b623e'/>
<id>1db1573bc59f7c91fa2867e4cbea73494d5b623e</id>
<content type='text'>
max_threads is initialized once by fork_init()-&gt;set_max_threads(), and
thereafter is mostly read in hot path, such as copy_process().

The fact that it is mostly read and not written to makes it candidates for
__read_mostly declarations.

I have already tested on my machine(arm64,256core,kernel-7.1.3) with
'hackbench -P -l 500 -g 100/500/1000/2000' and the results show that there
is an average of 13% improvement in performance.

before patch:
	hackbench -g    100      500      1000      2000
                    1.094    4.651    13.305    36.322

after patch:
	hackbench -g    100      500      1000      2000
                    0.823    4.487    11.107    32.987

Above data are the average values obtained from multiple tests, and there
was indeed some fluctuation in the data during the tests.

Link: https://lore.kernel.org/20260707092354.465847-1-jansef.jian@hj-micro.com
Signed-off-by: JianChunfu &lt;jansef.jian@hj-micro.com&gt;
Reviewed-by: Lorenzo Stoakes &lt;ljs@kernel.org&gt;
Cc: Dietmar Eggemann &lt;dietmar.eggemann@arm.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Kees Cook &lt;kees@kernel.org&gt;
Cc: Liam R. Howlett &lt;liam@infradead.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
max_threads is initialized once by fork_init()-&gt;set_max_threads(), and
thereafter is mostly read in hot path, such as copy_process().

The fact that it is mostly read and not written to makes it candidates for
__read_mostly declarations.

I have already tested on my machine(arm64,256core,kernel-7.1.3) with
'hackbench -P -l 500 -g 100/500/1000/2000' and the results show that there
is an average of 13% improvement in performance.

before patch:
	hackbench -g    100      500      1000      2000
                    1.094    4.651    13.305    36.322

after patch:
	hackbench -g    100      500      1000      2000
                    0.823    4.487    11.107    32.987

Above data are the average values obtained from multiple tests, and there
was indeed some fluctuation in the data during the tests.

Link: https://lore.kernel.org/20260707092354.465847-1-jansef.jian@hj-micro.com
Signed-off-by: JianChunfu &lt;jansef.jian@hj-micro.com&gt;
Reviewed-by: Lorenzo Stoakes &lt;ljs@kernel.org&gt;
Cc: Dietmar Eggemann &lt;dietmar.eggemann@arm.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Kees Cook &lt;kees@kernel.org&gt;
Cc: Liam R. Howlett &lt;liam@infradead.org&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Cc: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'perf/urgent' into perf/core, to pick up fixes</title>
<updated>2026-07-31T09:41:07+00:00</updated>
<author>
<name>Ingo Molnar</name>
<email>mingo@kernel.org</email>
</author>
<published>2026-07-31T09:41:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f70494ac4c07bcd3c5d2d8af96591032c69d9d44'/>
<id>f70494ac4c07bcd3c5d2d8af96591032c69d9d44</id>
<content type='text'>
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Signed-off-by: Ingo Molnar &lt;mingo@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>smp: Use task-local IPI cpumask in smp_call_function_many_cond()</title>
<updated>2026-07-16T07:24:55+00:00</updated>
<author>
<name>Chuyi Zhou</name>
<email>zhouchuyi@bytedance.com</email>
</author>
<published>2026-07-09T12:29:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=9a560af15fd31b3b93235b1584a2509445a17963'/>
<id>9a560af15fd31b3b93235b1584a2509445a17963</id>
<content type='text'>
smp_call_function_many_cond() uses the per-CPU cfd-&gt;cpumask as the list
of remote CPUs to wait for. That is safe while the caller remains pinned
to the current CPU for the whole operation, because another task cannot
run on the same CPU and reuse the per-CPU mask.

The synchronous wait is the long-latency part of the operation. To make
that wait preemptible, the mask iterated by csd_lock_wait() must remain
stable even if the task is preempted or migrates. If the wait used the
per-CPU cfd-&gt;cpumask after dropping CPU pinning, another task scheduled
on the original CPU could enter smp_call_function_many_cond() and
overwrite the mask while the first task is still iterating it.

Give each task private IPI cpumask storage and use it as the wait mask in
smp_call_function_many_cond(). Other cpumask storage choices do not fit
this use case:

 - Per-CPU storage is the state that becomes unsafe once the wait is
   made preemptible. After the caller drops CPU pinning, another task
   scheduled on the original CPU can enter smp_call_function_many_cond()
   and reuse the same per-CPU mask.

 - Stack storage is not suitable for large NR_CPUS or
   CONFIG_CPUMASK_OFFSTACK=y configurations. The wait mask needs to
   scale with cpumask_size(), and putting that storage on the stack is
   not acceptable on large systems.

 - Allocating the mask inside smp_call_function_many_cond() would put an
   allocation and a failure path in the generic IPI path. A sleeping
   allocation is not suitable because callers have historically only
   provided a preempt-disabled context, not a sleepable one. GFP_ATOMIC
   would avoid sleeping, but a failure fallback would make the latency
   improvement opportunistic instead of guaranteed.

The users are not limited to a small, pre-identifiable class of tasks. On
x86, ordinary tasks can reach this path through TLB flushes during exit,
unmap and reclaim, so allocating the mask only for a known subset of
tasks is not straightforward.

The memory cost is explicit: one word is added to task_struct. When
cpumask_size() fits in that word, the mask is stored inline and no
separate allocation is needed. Larger systems allocate cpumask_size() per
task; on x86-64 NR_CPUS=8192 this is 1 KiB per task. For context,
x86 already carries several KiB of per-task architecture and FPU state,
depending on the enabled features and configuration. That does not make
the extra cpumask free, but it puts the large-NR_CPUS case in
perspective.

Signed-off-by: Chuyi Zhou &lt;zhouchuyi@bytedance.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@kernel.org&gt;
Tested-by: Paul E. McKenney &lt;paulmck@kernel.org&gt;
Reviewed-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Link: https://patch.msgid.link/20260709122933.4021501-5-zhouchuyi@bytedance.com
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
smp_call_function_many_cond() uses the per-CPU cfd-&gt;cpumask as the list
of remote CPUs to wait for. That is safe while the caller remains pinned
to the current CPU for the whole operation, because another task cannot
run on the same CPU and reuse the per-CPU mask.

The synchronous wait is the long-latency part of the operation. To make
that wait preemptible, the mask iterated by csd_lock_wait() must remain
stable even if the task is preempted or migrates. If the wait used the
per-CPU cfd-&gt;cpumask after dropping CPU pinning, another task scheduled
on the original CPU could enter smp_call_function_many_cond() and
overwrite the mask while the first task is still iterating it.

Give each task private IPI cpumask storage and use it as the wait mask in
smp_call_function_many_cond(). Other cpumask storage choices do not fit
this use case:

 - Per-CPU storage is the state that becomes unsafe once the wait is
   made preemptible. After the caller drops CPU pinning, another task
   scheduled on the original CPU can enter smp_call_function_many_cond()
   and reuse the same per-CPU mask.

 - Stack storage is not suitable for large NR_CPUS or
   CONFIG_CPUMASK_OFFSTACK=y configurations. The wait mask needs to
   scale with cpumask_size(), and putting that storage on the stack is
   not acceptable on large systems.

 - Allocating the mask inside smp_call_function_many_cond() would put an
   allocation and a failure path in the generic IPI path. A sleeping
   allocation is not suitable because callers have historically only
   provided a preempt-disabled context, not a sleepable one. GFP_ATOMIC
   would avoid sleeping, but a failure fallback would make the latency
   improvement opportunistic instead of guaranteed.

The users are not limited to a small, pre-identifiable class of tasks. On
x86, ordinary tasks can reach this path through TLB flushes during exit,
unmap and reclaim, so allocating the mask only for a known subset of
tasks is not straightforward.

The memory cost is explicit: one word is added to task_struct. When
cpumask_size() fits in that word, the mask is stored inline and no
separate allocation is needed. Larger systems allocate cpumask_size() per
task; on x86-64 NR_CPUS=8192 this is 1 KiB per task. For context,
x86 already carries several KiB of per-task architecture and FPU state,
depending on the enabled features and configuration. That does not make
the extra cpumask free, but it puts the large-NR_CPUS case in
perspective.

Signed-off-by: Chuyi Zhou &lt;zhouchuyi@bytedance.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@kernel.org&gt;
Tested-by: Paul E. McKenney &lt;paulmck@kernel.org&gt;
Reviewed-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Link: https://patch.msgid.link/20260709122933.4021501-5-zhouchuyi@bytedance.com
</pre>
</div>
</content>
</entry>
<entry>
<title>uprobes/x86: Remove struct uprobe_trampoline object</title>
<updated>2026-07-03T14:30:35+00:00</updated>
<author>
<name>Jiri Olsa</name>
<email>jolsa@kernel.org</email>
</author>
<published>2026-07-03T11:49:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=38af0dd6a266057002eacb170c08298ea912fb0a'/>
<id>38af0dd6a266057002eacb170c08298ea912fb0a</id>
<content type='text'>
Removing struct uprobe_trampoline object and it's tracking code,
because it's not needed. We can do same thing directly on top of
struct vm_area_struct objects.

This makes the code simpler and allows easy propagation of the
trampoline vma object into child process in following change.

Note the original code called destroy_uprobe_trampoline if the
optimiation failed, but it only freed the struct uprobe_trampoline
object, not the vma. The new vma leak is fixed in following change.

Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Oleg Nesterov &lt;oleg@redhat.com&gt;
Acked-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Link: https://patch.msgid.link/20260703114917.238144-3-jolsa@kernel.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Removing struct uprobe_trampoline object and it's tracking code,
because it's not needed. We can do same thing directly on top of
struct vm_area_struct objects.

This makes the code simpler and allows easy propagation of the
trampoline vma object into child process in following change.

Note the original code called destroy_uprobe_trampoline if the
optimiation failed, but it only freed the struct uprobe_trampoline
object, not the vma. The new vma leak is fixed in following change.

Signed-off-by: Jiri Olsa &lt;jolsa@kernel.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Oleg Nesterov &lt;oleg@redhat.com&gt;
Acked-by: Andrii Nakryiko &lt;andrii@kernel.org&gt;
Link: https://patch.msgid.link/20260703114917.238144-3-jolsa@kernel.org
</pre>
</div>
</content>
</entry>
</feed>
