linux-stable.git/kernel, branch linux-6.1.y Linux kernel stable tree cgroup/cpuset: Reset DL migration state on can_attach() failure 2026-06-19T11:37:25+00:00 Guopeng Zhang zhangguopeng@kylinos.cn 2026-05-22T20:51:17+00:00 f8a8358832f3b812264560361a5ca1b6725da03a [ Upstream commit 4a39eda5fdd867fc39f3c039714dd432cee00268 ] cpuset_can_attach() accumulates temporary SCHED_DEADLINE migration state in the destination cpuset while walking the taskset. If a later task_can_attach() or security_task_setscheduler() check fails, cgroup_migrate_execute() treats cpuset as the failing subsystem and does not call cpuset_cancel_attach() for it. The partially accumulated state is then left behind and can be consumed by a later attach, corrupting cpuset DL task accounting and pending DL bandwidth accounting. Reset the pending DL migration state from the common error exit when ret is non-zero. Successful can_attach() keeps the state for cpuset_attach() or cpuset_cancel_attach(). Fixes: 2ef269ef1ac0 ("cgroup/cpuset: Free DL BW in case can_attach() fails") Cc: stable@vger.kernel.org # v6.10+ Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn> Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Chen Ridong <chenridong@huaweicloud.com> Reviewed-by: Waiman Long <longman@redhat.com> [ omitted upstream context line `cs->dl_bw_cpu = cpu;` ] Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 4a39eda5fdd867fc39f3c039714dd432cee00268 ]

cpuset_can_attach() accumulates temporary SCHED_DEADLINE migration
state in the destination cpuset while walking the taskset.

If a later task_can_attach() or security_task_setscheduler() check
fails, cgroup_migrate_execute() treats cpuset as the failing subsystem
and does not call cpuset_cancel_attach() for it. The partially
accumulated state is then left behind and can be consumed by a later
attach, corrupting cpuset DL task accounting and pending DL bandwidth
accounting.

Reset the pending DL migration state from the common error exit when
ret is non-zero. Successful can_attach() keeps the state for
cpuset_attach() or cpuset_cancel_attach().

Fixes: 2ef269ef1ac0 ("cgroup/cpuset: Free DL BW in case can_attach() fails")
Cc: stable@vger.kernel.org # v6.10+
Signed-off-by: Guopeng Zhang <zhangguopeng@kylinos.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Chen Ridong <chenridong@huaweicloud.com>
Reviewed-by: Waiman Long <longman@redhat.com>
[ omitted upstream context line `cs->dl_bw_cpu = cpu;` ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tracing/probes: Limit size of event probe to 3K 2026-06-19T11:37:24+00:00 Steven Rostedt rostedt@goodmis.org 2026-05-15T14:48:40+00:00 e4f9863a1cf912dbde45d377de08397b43023efb [ Upstream commit b2aa3b4d64e460ac606f386c24e7d8a873ce6f1a ] There currently isn't a max limit an event probe can be. One could make an event greater than PAGE_SIZE, which makes the event useless because if it's bigger than the max event that can be recorded into the ring buffer, then it will never be recorded. A event probe should never need to be greater than 3K, so make that the max size. As long as the max is less than the max that can be recorded onto the ring buffer, it should be fine. Cc: stable@vger.kernel.org Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Fixes: 93ccae7a22274 ("tracing/kprobes: Support basic types on dynamic events") Link: https://patch.msgid.link/20260428122302.706610ba@gandalf.local.home Signed-off-by: Steven Rostedt <rostedt@goodmis.org> [ changed `ctx->offset` to `offset` and `goto fail` to `goto out` ] Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit b2aa3b4d64e460ac606f386c24e7d8a873ce6f1a ]

There currently isn't a max limit an event probe can be. One could make an
event greater than PAGE_SIZE, which makes the event useless because if
it's bigger than the max event that can be recorded into the ring buffer,
then it will never be recorded.

A event probe should never need to be greater than 3K, so make that the
max size. As long as the max is less than the max that can be recorded
onto the ring buffer, it should be fine.

Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Fixes: 93ccae7a22274 ("tracing/kprobes: Support basic types on dynamic events")
Link: https://patch.msgid.link/20260428122302.706610ba@gandalf.local.home
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
[ changed `ctx->offset` to `offset` and `goto fail` to `goto out` ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func() 2026-06-19T11:37:21+00:00 David Carlier devnexen@gmail.com 2026-05-11T00:10:41+00:00 36ff362235307af95152d510b53c2d9b8773a342 [ Upstream commit fad217e16fded7f3c09f8637b0f6a224d58b5f2e ] When a tracepoint goes through the 0 -> 1 transition, tracepoint_add_func() invokes the subsystem's ext->regfunc() before attempting to install the new probe via func_add(). If func_add() then fails (for example, when allocate_probes() cannot allocate a new probe array under memory pressure and returns -ENOMEM), the function returns the error without calling the matching ext->unregfunc(), leaving the side effects of regfunc() behind with no installed probe to justify them. For syscall tracepoints this is particularly unpleasant: syscall_regfunc() bumps sys_tracepoint_refcount and sets SYSCALL_TRACEPOINT on every task. After a leaked failure, the refcount is stuck at a non-zero value with no consumer, and every task continues paying the syscall trace entry/exit overhead until reboot. Other subsystems providing regfunc()/unregfunc() pairs exhibit similarly scoped persistent state. Mirror the existing 1 -> 0 cleanup and call ext->unregfunc() in the func_add() error path, gated on the same condition used there so the unwind is symmetric with the registration. Fixes: 8cf868affdc4 ("tracing: Have the reg function allow to fail") Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://patch.msgid.link/20260413190601.21993-1-devnexen@gmail.com Signed-off-by: David Carlier <devnexen@gmail.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> [ changed `tp->ext->unregfunc` to `tp->unregfunc` to match older struct layout ] Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit fad217e16fded7f3c09f8637b0f6a224d58b5f2e ]

When a tracepoint goes through the 0 -> 1 transition, tracepoint_add_func()
invokes the subsystem's ext->regfunc() before attempting to install the
new probe via func_add(). If func_add() then fails (for example, when
allocate_probes() cannot allocate a new probe array under memory pressure
and returns -ENOMEM), the function returns the error without calling the
matching ext->unregfunc(), leaving the side effects of regfunc() behind
with no installed probe to justify them.

For syscall tracepoints this is particularly unpleasant: syscall_regfunc()
bumps sys_tracepoint_refcount and sets SYSCALL_TRACEPOINT on every task.
After a leaked failure, the refcount is stuck at a non-zero value with no
consumer, and every task continues paying the syscall trace entry/exit
overhead until reboot. Other subsystems providing regfunc()/unregfunc()
pairs exhibit similarly scoped persistent state.

Mirror the existing 1 -> 0 cleanup and call ext->unregfunc() in the
func_add() error path, gated on the same condition used there so the
unwind is symmetric with the registration.

Fixes: 8cf868affdc4 ("tracing: Have the reg function allow to fail")
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20260413190601.21993-1-devnexen@gmail.com
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
[ changed `tp->ext->unregfunc` to `tp->unregfunc` to match older struct layout ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sched: Use u64 for bandwidth ratio calculations 2026-06-19T11:37:19+00:00 Joseph Salisbury joseph.salisbury@oracle.com 2026-05-02T23:58:03+00:00 604f4ec9a234b8f23d7f0a919981f9bc118ed6ac [ Upstream commit c6e80201e057dfb7253385e60bf541121bf5dc33 ] to_ratio() computes BW_SHIFT-scaled bandwidth ratios from u64 period and runtime values, but it returns unsigned long. tg_rt_schedulable() also stores the current group limit and the accumulated child sum in unsigned long. On 32-bit builds, large bandwidth ratios can be truncated and the RT group sum can wrap when enough siblings are present. That can let an overcommitted RT hierarchy pass the schedulability check, and it also narrows the helper result for other callers. Return u64 from to_ratio() and use u64 for the RT group totals so bandwidth ratios are preserved and compared at full width on both 32-bit and 64-bit builds. Fixes: b40b2e8eb521 ("sched: rt: multi level group constraints") Assisted-by: Codex:GPT-5 Signed-off-by: Joseph Salisbury <joseph.salisbury@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260403210014.2713404-1-joseph.salisbury@oracle.com [ dropped `extern` keyword from `to_ratio()` declaration ] Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit c6e80201e057dfb7253385e60bf541121bf5dc33 ]

to_ratio() computes BW_SHIFT-scaled bandwidth ratios from u64 period and
runtime values, but it returns unsigned long.  tg_rt_schedulable() also
stores the current group limit and the accumulated child sum in unsigned
long.

On 32-bit builds, large bandwidth ratios can be truncated and the RT
group sum can wrap when enough siblings are present.  That can let an
overcommitted RT hierarchy pass the schedulability check, and it also
narrows the helper result for other callers.

Return u64 from to_ratio() and use u64 for the RT group totals so
bandwidth ratios are preserved and compared at full width on both 32-bit
and 64-bit builds.

Fixes: b40b2e8eb521 ("sched: rt: multi level group constraints")
Assisted-by: Codex:GPT-5
Signed-off-by: Joseph Salisbury <joseph.salisbury@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260403210014.2713404-1-joseph.salisbury@oracle.com
[ dropped `extern` keyword from `to_ratio()` declaration ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pidfd: refuse access to tasks that have started exiting harder 2026-06-19T11:37:15+00:00 Christian Brauner brauner@kernel.org 2026-05-18T08:32:11+00:00 ed5996c5906a638a97deb9c8bc0e22e94d445ea5 commit 62c4d31d78294bd61cf3403626b789e854357177 upstream. The recent ptrace fix closed a hole where someone could rely on task->mm becoming NULL during do_exit() to bypass dumpability checks. This api here leans on on the very same check and so inherits the fix. But there is no good reason to let it succeed at all once the target has entered do_exit(). PF_EXITING is set by exit_signals() at the very top of do_exit(), before exit_mm() and exit_files() run. Once we observe it, the task is committed to dying and exit_files() will release the fdtable shortly. Fixes: 8649c322f75c ("pid: Implement pidfd_getfd syscall") Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260518-obgleich-petersilie-2d77ccccf9b9@brauner Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 62c4d31d78294bd61cf3403626b789e854357177 upstream.

The recent ptrace fix closed a hole where someone could rely on task->mm
becoming NULL during do_exit() to bypass dumpability checks. This api
here leans on on the very same check and so inherits the fix.

But there is no good reason to let it succeed at all once the target has
entered do_exit(). PF_EXITING is set by exit_signals() at the very top
of do_exit(), before exit_mm() and exit_files() run. Once we observe it,
the task is committed to dying and exit_files() will release the fdtable
shortly.

Fixes: 8649c322f75c ("pid: Implement pidfd_getfd syscall")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260518-obgleich-petersilie-2d77ccccf9b9@brauner
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
time: Fix off-by-one in settimeofday() usec validation 2026-06-19T11:37:10+00:00 Naveen Kumar Chaudhary naveen.osdev@gmail.com 2026-06-02T18:07:37+00:00 43c2067bb3fcecdb65c528af2b3c5f1bc5f8c2bd [ Upstream commit ce4abda5e12622f33450159e76c8f56d28d7f03d ] The validation check uses '>' instead of '>=' when comparing tv_usec against USEC_PER_SEC, allowing the value 1000000 through. After conversion to nanoseconds (*= 1000), this produces tv_nsec == NSEC_PER_SEC, violating the timespec invariant that tv_nsec must be less than NSEC_PER_SEC. Use '>=' to reject tv_usec values that are not in the valid range of 0 to 999999. Fixes: 5e0fb1b57bea ("y2038: time: avoid timespec usage in settimeofday()") Signed-off-by: Naveen Kumar Chaudhary <naveen.osdev@gmail.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Acked-by: John Stultz <jstultz@google.com> Link: https://patch.msgid.link/4rikk44zew3s6577dugmx4jyblz7o5c57niuap6ct3td5yfm6w@gh7pcumg7qor Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit ce4abda5e12622f33450159e76c8f56d28d7f03d ]

The validation check uses '>' instead of '>=' when comparing tv_usec
against USEC_PER_SEC, allowing the value 1000000 through. After
conversion to nanoseconds (*= 1000), this produces tv_nsec ==
NSEC_PER_SEC, violating the timespec invariant that tv_nsec must be
less than NSEC_PER_SEC.

Use '>=' to reject tv_usec values that are not in the valid range of
0 to 999999.

Fixes: 5e0fb1b57bea ("y2038: time: avoid timespec usage in settimeofday()")
Signed-off-by: Naveen Kumar Chaudhary <naveen.osdev@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Acked-by: John Stultz <jstultz@google.com>
Link: https://patch.msgid.link/4rikk44zew3s6577dugmx4jyblz7o5c57niuap6ct3td5yfm6w@gh7pcumg7qor
Signed-off-by: Sasha Levin <sashal@kernel.org>
signal: clear JOBCTL_PENDING_MASK for caller in zap_other_threads() 2026-06-19T11:37:10+00:00 Aleksandr Nogikh nogikh@google.com 2026-05-21T14:22:40+00:00 f8d720bc2e35d568c18be0644e92a468de428370 [ Upstream commit 90918794a4e2c3b440f8fcf3847765a8b1d81b25 ] When a multi-threaded process receives a stop signal (e.g., SIGSTOP), do_signal_stop() sets JOBCTL_STOP_PENDING and JOBCTL_STOP_CONSUME on all threads and sets signal->group_stop_count to the number of threads. If one of the threads concurrently calls execve(), de_thread() invokes zap_other_threads() to kill all other threads. zap_other_threads() aborts the pending group stop by resetting signal->group_stop_count to 0 and clears the JOBCTL_PENDING_MASK for all other threads. However, it fails to clear the job control flags for the calling thread. When execve() completes, the calling thread returns to user mode and checks for pending signals. Seeing the stale JOBCTL_STOP_PENDING flag, it calls do_signal_stop(), which invokes task_participate_group_stop(). Since JOBCTL_STOP_CONSUME is still set, it attempts to decrement the already-zero signal->group_stop_count, triggering a warning: sig->group_stop_count == 0 WARNING: CPU: 1 PID: 6475 at kernel/signal.c:373 task_participate_group_stop+0x215/0x2d0 Call Trace: <TASK> do_signal_stop+0x3be/0x5c0 kernel/signal.c:2619 get_signal+0xa8c/0x1330 kernel/signal.c:2884 arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x8c/0x4d0 kernel/entry/common.c:98 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> Fix this race condition by clearing the JOBCTL_PENDING_MASK for the calling thread in zap_other_threads(), ensuring it does not retain any stale job control state after the thread group is destroyed. This aligns with other functions that tear down a thread group and abort group stops, such as zap_process() and complete_signal(), which correctly clear these flags for all threads including the current one. Fixes: 39efa3ef3a37 ("signal: Use GROUP_STOP_PENDING to stop once for a single group stop") Assisted-by: Gemini:gemini-3.1-pro-preview Gemini:gemini-3-flash-preview syzbot Reported-by: syzbot+b109633ea805cac54a61@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=b109633ea805cac54a61 Link: https://syzkaller.appspot.com/ai_job?id=d70208cc-862b-4fe3-bf02-3031e10cd0b3 Signed-off-by: Aleksandr Nogikh <nogikh@google.com> Link: https://patch.msgid.link/20260521142240.2973022-1-nogikh@google.com Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 90918794a4e2c3b440f8fcf3847765a8b1d81b25 ]

When a multi-threaded process receives a stop signal (e.g., SIGSTOP),
do_signal_stop() sets JOBCTL_STOP_PENDING and JOBCTL_STOP_CONSUME on all
threads and sets signal->group_stop_count to the number of threads. If
one of the threads concurrently calls execve(), de_thread() invokes
zap_other_threads() to kill all other threads. zap_other_threads()
aborts the pending group stop by resetting signal->group_stop_count to 0
and clears the JOBCTL_PENDING_MASK for all other threads. However, it
fails to clear the job control flags for the calling thread.

When execve() completes, the calling thread returns to user mode and
checks for pending signals. Seeing the stale JOBCTL_STOP_PENDING flag,
it calls do_signal_stop(), which invokes task_participate_group_stop().
Since JOBCTL_STOP_CONSUME is still set, it attempts to decrement the
already-zero signal->group_stop_count, triggering a warning:

sig->group_stop_count == 0
WARNING: CPU: 1 PID: 6475 at kernel/signal.c:373
task_participate_group_stop+0x215/0x2d0
Call Trace:
 <TASK>
 do_signal_stop+0x3be/0x5c0 kernel/signal.c:2619
 get_signal+0xa8c/0x1330 kernel/signal.c:2884
 arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x8c/0x4d0 kernel/entry/common.c:98
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
 </TASK>

Fix this race condition by clearing the JOBCTL_PENDING_MASK for the
calling thread in zap_other_threads(), ensuring it does not retain any
stale job control state after the thread group is destroyed. This aligns
with other functions that tear down a thread group and abort group
stops, such as zap_process() and complete_signal(), which correctly
clear these flags for all threads including the current one.

Fixes: 39efa3ef3a37 ("signal: Use GROUP_STOP_PENDING to stop once for a single group stop")
Assisted-by: Gemini:gemini-3.1-pro-preview Gemini:gemini-3-flash-preview syzbot
Reported-by: syzbot+b109633ea805cac54a61@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=b109633ea805cac54a61
Link: https://syzkaller.appspot.com/ai_job?id=d70208cc-862b-4fe3-bf02-3031e10cd0b3
Signed-off-by: Aleksandr Nogikh <nogikh@google.com>
Link: https://patch.msgid.link/20260521142240.2973022-1-nogikh@google.com
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
tracing: Avoid NULL return from hist_field_name() on truncation 2026-06-01T15:39:42+00:00 David Carlier devnexen@gmail.com 2026-05-08T19:57:47+00:00 0402a1d3ddec565132867337ed44514a09d84728 [ Upstream commit 576ec047d20b368b43c4d5db98c4f2e0f3c101ec ] hist_field_name() returns "" everywhere except the fully-qualified VAR_REF/EXPR case, where snprintf() truncation returns NULL early and bypasses the bottom NULL->"" guard. Callers don't expect NULL: strcat(expr, hist_field_name(field, 0)) at trace_events_hist.c:1758 and the strcmp() in the sort-key match loop at :4804 both deref it. system and event_name are bounded by MAX_EVENT_NAME_LEN, but the field name on a VAR_REF is kstrdup'd from a histogram variable name parsed out of the trigger string and has no length cap, so a long enough var name in a fully qualified reference can reach the truncation path. Keep the length check but leave field_name as "" on overflow. Link: https://patch.msgid.link/20260508195747.25492-1-devnexen@gmail.com Fixes: 5ec1d1e97de1 ("tracing: Rebuild full_name on each hist_field_name() call") Signed-off-by: David Carlier <devnexen@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 576ec047d20b368b43c4d5db98c4f2e0f3c101ec ]

hist_field_name() returns "" everywhere except the fully-qualified
VAR_REF/EXPR case, where snprintf() truncation returns NULL early
and bypasses the bottom NULL->"" guard. Callers don't expect NULL:
strcat(expr, hist_field_name(field, 0)) at trace_events_hist.c:1758
and the strcmp() in the sort-key match loop at :4804 both deref it.

system and event_name are bounded by MAX_EVENT_NAME_LEN, but the
field name on a VAR_REF is kstrdup'd from a histogram variable
name parsed out of the trigger string and has no length cap, so
a long enough var name in a fully qualified reference can reach
the truncation path.

Keep the length check but leave field_name as "" on overflow.

Link: https://patch.msgid.link/20260508195747.25492-1-devnexen@gmail.com
Fixes: 5ec1d1e97de1 ("tracing: Rebuild full_name on each hist_field_name() call")
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT 2026-06-01T15:39:39+00:00 Jiayuan Chen jiayuan.chen@linux.dev 2026-03-30T07:32:29+00:00 2dc79362302922cb18f35e262712b5e58de65442 [ Upstream commit 91840be8f710370607f949a627e070896faeddb8 ] On PREEMPT_RT, non-HARD irq_work runs in per-CPU kthreads via run_irq_workd(), so irq_work_sync() uses rcuwait() to wait for BUSY==0. After irq_work_single() clears BUSY via atomic_cmpxchg(), it still dereferences @work for irq_work_is_hard() and rcuwait_wake_up(). An irq_work_sync() caller on another CPU that enters after BUSY is cleared can observe BUSY==0 immediately, return, and free the work before those accesses complete — causing a use-after-free. Fix this by wrapping run_irq_workd() in guard(rcu)() so that the entire irq_work_single() execution is within an RCU read-side critical section. Then add synchronize_rcu() in irq_work_sync() after rcuwait_wait_event() to ensure the caller waits for the RCU grace period before returning, preventing premature frees. Fixes: 810979682ccc ("irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support.") Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Suggested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://patch.msgid.link/20260330073234.303732-1-jiayuan.chen@linux.dev Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 91840be8f710370607f949a627e070896faeddb8 ]

On PREEMPT_RT, non-HARD irq_work runs in per-CPU kthreads via
run_irq_workd(), so irq_work_sync() uses rcuwait() to wait for BUSY==0.

After irq_work_single() clears BUSY via atomic_cmpxchg(), it still
dereferences @work for irq_work_is_hard() and rcuwait_wake_up().

An irq_work_sync() caller on another CPU that enters after BUSY is cleared
can observe BUSY==0 immediately, return, and free the work before those
accesses complete — causing a use-after-free.

Fix this by wrapping run_irq_workd() in guard(rcu)() so that the entire
irq_work_single() execution is within an RCU read-side critical
section. Then add synchronize_rcu() in irq_work_sync() after
rcuwait_wait_event() to ensure the caller waits for the RCU grace period
before returning, preventing premature frees.

Fixes: 810979682ccc ("irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support.")
Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20260330073234.303732-1-jiayuan.chen@linux.dev
Signed-off-by: Sasha Levin <sashal@kernel.org>
tracing: Do not call map->ops->elt_free() if elt_alloc() fails 2026-06-01T15:39:36+00:00 Masami Hiramatsu (Google) mhiramat@kernel.org 2026-05-21T04:49:14+00:00 b427e9f6d81c9341cba23ef92f860f99f830d91d commit 8f0f5c4fb9df0e19a341e0c6ed8dc4fda9124f03 upstream. In paths where tracing_map_elt_alloc() failed to allocate objects, the map->ops->elt_alloc() call was never successful. In this case, map->ops->elt_free() should not be called. Link: https://sashiko.dev/#/patchset/20260520223101.34710-1-rosenp%40gmail.com Cc: stable@vger.kernel.org Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Rosen Penev <rosenp@gmail.com> Reported-by: Sashiko <sashiko-bot@kernel.org> Fixes: 2734b629525a ("tracing: Add per-element variable support to tracing_map") Link: https://patch.msgid.link/177933895460.108746.5396070821443932634.stgit@devnote2 Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8f0f5c4fb9df0e19a341e0c6ed8dc4fda9124f03 upstream.

In paths where tracing_map_elt_alloc() failed to allocate objects,
the map->ops->elt_alloc() call was never successful. In this case,
map->ops->elt_free() should not be called.

Link: https://sashiko.dev/#/patchset/20260520223101.34710-1-rosenp%40gmail.com

Cc: stable@vger.kernel.org
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Rosen Penev <rosenp@gmail.com>
Reported-by: Sashiko <sashiko-bot@kernel.org>
Fixes: 2734b629525a ("tracing: Add per-element variable support to tracing_map")
Link: https://patch.msgid.link/177933895460.108746.5396070821443932634.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>