linux-stable.git/kernel, branch v6.12.91

sched_ext: Guard scx_dsq_move() against NULL kit->dsq after failed iter_new

2026-05-23T11:05:01+00:00

[ Upstream commit 4fda9f0e7c950da4fe03cedeb2ac818edf5d03e9 ]

bpf_iter_scx_dsq_new() clears kit->dsq on failure and
bpf_iter_scx_dsq_{next,destroy}() guard against that. scx_dsq_move() doesn't -
it dereferences kit->dsq immediately, so a BPF program that calls
scx_bpf_dsq_move[_vtime]() after a failed iter_new oopses the kernel.

Return false if kit->dsq is NULL.

Fixes: 4c30f5ce4f7a ("sched_ext: Implement scx_bpf_dispatch[_vtime]_from_dsq()")
Cc: stable@vger.kernel.org # v6.12+
Reported-by: Chris Mason 
Signed-off-by: Tejun Heo 
Reviewed-by: Andrea Righi 
[ dropped the `struct scx_sched *sch` declaration and `sch = src_dsq->sched` line ]
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

audit: enforce AUDIT_LOCKED for AUDIT_TRIM and AUDIT_MAKE_EQUIV

2026-05-23T11:04:59+00:00

commit f9e1c1324b4d98d591a6f7568fdebf5cf456dfc2 upstream.

AUDIT_ADD_RULE and AUDIT_DEL_RULE correctly check for AUDIT_LOCKED
and return -EPERM, but AUDIT_TRIM and AUDIT_MAKE_EQUIV do not. This
allows a process with CAP_AUDIT_CONTROL to modify directory tree
watches and equivalence mappings even when the audit configuration
has been locked, undermining the purpose of the lock.

Add AUDIT_LOCKED checks to both commands.

Cc: stable@vger.kernel.org
Reviewed-by: Ricardo Robaina 
Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Sergio Correia 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

audit: fix incorrect inheritable capability in CAPSET records

2026-05-23T11:04:58+00:00

commit e4a640475e43f406fdfd56d370b1f34b0cbbc18d upstream.

__audit_log_capset() records the effective capability set into the
inheritable field due to a copy-paste error. Every CAPSET audit
record therefore reports cap_pi (process inheritable) with the value
of cap_effective instead of cap_inheritable.

This silently corrupts audit data used for compliance and forensic
analysis: an attacker who modifies inheritable capabilities to
prepare for a privilege-escalating exec would have the change masked
in the audit trail.

The bug has been present since the original introduction of CAPSET
audit records in 2008.

Cc: stable@vger.kernel.org
Fixes: e68b75a027bb ("When the capset syscall is used it is not possible for audit to record the actual capbilities being added/removed.  This patch adds a new record type which emits the target pid and the eff, inh, and perm cap sets.")
Reviewed-by: Ricardo Robaina 
Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Sergio Correia 
Signed-off-by: Paul Moore 
Signed-off-by: Greg Kroah-Hartman

workqueue: Fix wq->cpu_pwq leak in alloc_and_link_pwqs() WQ_UNBOUND path

2026-05-23T11:04:58+00:00

commit 0143033dc22cdff912cfc13419f5db92fea3b4cb upstream.

For WQ_UNBOUND workqueues, alloc_and_link_pwqs() allocates wq->cpu_pwq
via alloc_percpu() and then calls apply_workqueue_attrs_locked(). On
failure it returns the error directly, bypassing the enomem: label
which holds the only free_percpu(wq->cpu_pwq) in this function.

The caller's error path kfree()s wq without touching wq->cpu_pwq,
leaking one percpu pointer table (nr_cpu_ids * sizeof(void *) bytes) per
failed call.

If kmemleak is enabled, we can see:

  unreferenced object (percpu) 0xc0fffa5b121048 (size 8):
    comm "insmod", pid 776, jiffies 4294682844
    backtrace (crc 0):
      pcpu_alloc_noprof+0x665/0xac0
      __alloc_workqueue+0x33f/0xa20
      alloc_workqueue_noprof+0x60/0x100

Route the error through the existing enomem: cleanup and any error
before this one.

Cc: stable@kernel.org
Fixes: 636b927eba5b ("workqueue: Make unbound workqueues to use per-cpu pool_workqueues")
Signed-off-by: Breno Leitao 
Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

futex: Prevent lockup in requeue-PI during signal/ timeout wakeup

2026-05-23T11:04:56+00:00

[ Upstream commit bc7304f3ae20972d11db6e0b1b541c63feda5f05 ]

During wait-requeue-pi (task A) and requeue-PI (task B) the following
race can happen:

     Task A                             Task B
  futex_wait_requeue_pi()
    futex_setup_timer()
    futex_do_wait()
                                   futex_requeue()
                                        CLASS(hb, hb1)(&key1);
                                        CLASS(hb, hb2)(&key2);
        *timeout*
    futex_requeue_pi_wakeup_sync()
        requeue_state = Q_REQUEUE_PI_IGNORE

    *blocks on hb->lock*

                                        futex_proxy_trylock_atomic()
                                          futex_requeue_pi_prepare()
                                            Q_REQUEUE_PI_IGNORE => -EAGAIN
                                        double_unlock_hb(hb1, hb2)
                                         *retry*

Task B acquires both hb locks and attempts to acquire the PI-lock of the
top most waiter (task B). Task A is leaving early due to a signal/
timeout and started removing itself from the queue. It updates its
requeue_state but can not remove it from the list because this requires
the hb lock which is owned by task B.

Usually task A is able to swoop the lock after task B unlocked it.
However if task B is of higher priority then task A may not be able to
wake up in time and acquire the lock before task B gets it again.
Especially on a UP system where A is never scheduled.

As a result task A blocks on the lock and task B busy loops, trying to
make progress but live locks the system instead. Tragic.

This can be fixed by removing the top most waiter from the list in this
case. This allows task B to grab the next top waiter (if any) in the
next iteration and make progress.

Remove the top most waiter if futex_requeue_pi_prepare() fails.
Let the waiter conditionally remove itself from the list in
handle_early_requeue_pi_wakeup().

Fixes: 07d91ef510fb1 ("futex: Prevent requeue_pi() lock nesting issue on RT")
Reported-by: Moritz Klammler 
Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Thomas Gleixner 
Link: https://patch.msgid.link/20260428103425.dywXyPd3@linutronix.de
Closes: https://lore.kernel.org/all/VE1PR06MB6894BE61C173D802365BE19DFF4CA@VE1PR06MB6894.eurprd06.prod.outlook.com
Signed-off-by: Sasha Levin

sched/fair: Clear rel_deadline when initializing forked entities

2026-05-23T11:04:54+00:00

[ Upstream commit 3da56dc063cd77b9c0b40add930767fab4e389f3 ]

A yield-triggered crash can happen when a newly forked sched_entity
enters the fair class with se->rel_deadline unexpectedly set.

The failing sequence is:

  1. A task is forked while se->rel_deadline is still set.
  2. __sched_fork() initializes vruntime, vlag and other sched_entity
     state, but does not clear rel_deadline.
  3. On the first enqueue, enqueue_entity() calls place_entity().
  4. Because se->rel_deadline is set, place_entity() treats se->deadline
     as a relative deadline and converts it to an absolute deadline by
     adding the current vruntime.
  5. However, the forked entity's deadline is not a valid inherited
     relative deadline for this new scheduling instance, so the conversion
     produces an abnormally large deadline.
  6. If the task later calls sched_yield(), yield_task_fair() advances
     se->vruntime to se->deadline.
  7. The inflated vruntime is then used by the following enqueue path,
     where the vruntime-derived key can overflow when multiplied by the
     entity weight.
  8. This corrupts cfs_rq->sum_w_vruntime, breaks EEVDF eligibility
     calculation, and can eventually make all entities appear ineligible.
     pick_next_entity() may then return NULL unexpectedly, leading to a
     later NULL dereference.

A captured trace shows the effect clearly. Before yield, the entity's
vruntime was around:

  9834017729983308

After yield_task_fair() executed:

  se->vruntime = se->deadline

the vruntime jumped to:

  19668035460670230

and the deadline was later advanced further to:

  19668035463470230

This shows that the deadline had already become abnormally large before
yield_task_fair() copied it into vruntime.

rel_deadline is only meaningful when se->deadline really carries a
relative deadline that still needs to be placed against vruntime. A
freshly forked sched_entity should not inherit or retain this state.
Clear se->rel_deadline in __sched_fork(), together with the other
sched_entity runtime state, so that the first enqueue does not interpret
the new entity's deadline as a stale relative deadline.

Fixes: 82e9d0456e06 ("sched/fair: Avoid re-setting virtual deadline on 'migrations'")
Analyzed-by: Hui Tang 
Analyzed-by: Zhang Qiao 
Signed-off-by: Zicheng Qu 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://patch.msgid.link/20260424071113.1199600-1-quzicheng@huawei.com
Signed-off-by: Sasha Levin

tracing: branch: Fix inverted check on stat tracer registration

2026-05-23T11:04:52+00:00

[ Upstream commit 3b75dd76e64a04771861bb5647951c264919e563 ]

init_annotated_branch_stats() and all_annotated_branch_stats() check the
return value of register_stat_tracer() with "if (!ret)", but
register_stat_tracer() returns 0 on success and a negative errno on
failure. The inverted check causes the warning to be printed on every
successful registration, e.g.:

  Warning: could not register annotated branches stats

while leaving real failures silent. The initcall also returned a
hard-coded 1 instead of the actual error.

Invert the check and propagate ret so that the warning fires on real
errors and the initcall reports the correct status.

Cc: Mathieu Desnoyers 
Cc: Ingo Molnar 
Cc: Frederic Weisbecker 
Link: https://patch.msgid.link/20260420-tracing-v1-1-d8f4cd0d6af1@debian.org
Fixes: 002bb86d8d42 ("tracing/ftrace: separate events tracing and stats tracing engine")
Signed-off-by: Breno Leitao 
Acked-by: Masami Hiramatsu (Google) 
Signed-off-by: Steven Rostedt 
Signed-off-by: Sasha Levin

cgroup: Increment nr_dying_subsys_* from rmdir context

2026-05-23T11:04:52+00:00

[ Upstream commit 13e786b64bd3fd81c7eb22aa32bf8305c32f2ccf ]

Incrementing nr_dying_subsys_* in offline_css(), which is executed by
cgroup_offline_wq worker, leads to a race where user can see the value
to be 0 if he reads cgroup.stat after calling rmdir and before the worker
executes. This makes the user wrongly expect resources released by the
removed cgroup to be available for a new assignment.

Increment nr_dying_subsys_* from kill_css(), which is called from the
cgroup_rmdir() context.

Fixes: ab0312526867 ("cgroup: Show # of subsystem CSSes in cgroup.stat")
Signed-off-by: Petr Malat 
Signed-off-by: Tejun Heo 
Signed-off-by: Sasha Levin

cgroup/rdma: fix integer overflow in rdmacg_try_charge()

2026-05-23T11:04:51+00:00

[ Upstream commit c802f460dd485c1332b5a35e7adcfb2bc22536a2 ]

The expression `rpool->resources[index].usage + 1` is computed in int
arithmetic before being assigned to s64 variable `new`. When usage equals
INT_MAX (the default "max" value), the addition overflows to INT_MIN.
This negative value then passes the `new > max` check incorrectly,
allowing a charge that should be rejected and corrupting usage to
negative.

Fix by casting usage to s64 before the addition so the arithmetic is
done in 64-bit.

Fixes: 39d3e7584a68 ("rdmacg: Added rdma cgroup controller")
Signed-off-by: cuitao 
Reviewed-by: Michal Koutný 
Signed-off-by: Tejun Heo 
Signed-off-by: Sasha Levin

bpf: Validate node_id in arena_alloc_pages()

2026-05-23T11:04:42+00:00

[ Upstream commit 2845989f2ebaf7848e4eccf9a779daf3156ea0a5 ]

arena_alloc_pages() accepts a plain int node_id and forwards it through
the entire allocation chain without any bounds checking.

Validate node_id before passing it down the allocation chain in
arena_alloc_pages().

Fixes: 317460317a02 ("bpf: Introduce bpf_arena.")
Signed-off-by: Puranjay Mohan 
Reviewed-by: Emil Tsalapatis 
Link: https://lore.kernel.org/r/20260417152135.1383754-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin