linux-stable.git/kernel, branch v7.0.13

sched_ext: Don't warn on NULL cgrp_moving_from in scx_cgroup_move_task()

2026-06-19T11:48:12+00:00

[ Upstream commit 02e545c4297a26dbbc41df81b831e7f605bcd306 ]

A WARN fires when systemd's user manager writes "+cpu +memory +pids" to
its own subtree_control while a sched_ext scheduler is loaded:

  WARNING: at kernel/sched/ext.c:3227 scx_cgroup_move_task+0xa8/0xb0
   scx_cgroup_move_task+0xa8/0xb0
   sched_move_task+0x134/0x290
   cpu_cgroup_attach+0x39/0x70
   cgroup_migrate_execute+0x37d/0x450
   cgroup_update_dfl_csses+0x1e3/0x270
   cgroup_subtree_control_write+0x3e7/0x440

scx_cgroup_can_attach() arms cgrp_moving_from only when a task's cpu
cgroup changes. It can still be NULL when scx_cgroup_move_task() runs,
through this sequence:

  Step                               Result
  ---------------------------------  ----------------------------------
  1. cpu enabled on cgroup G         cpu css = A
  2. cpu toggled off then on for G   A killed, B created (same cgroup)
  3. an exiting task keeps A alive   migration skips it, A now stale
  4. +memory migrates G              stale A vs current B pulls cpu in
  5. cpu attach runs for all tasks   hits a live, cpu-unchanged task
  6. scx_cgroup_move_task() on it    cgrp_moving_from NULL -> WARN

The mismatch is that scx_cgroup_can_attach() keys on cgroup identity
while migration drives the move on css identity, so a NULL cgrp_moving_from
here is a legitimate css-only migration, not a missing prep.

The call is already gated on cgrp_moving_from, so just drop the warning.
ops.cgroup_prep_move() and ops.cgroup_move() stay paired.

Fixes: 819513666966 ("sched_ext: Add cgroup support")
Cc: stable@vger.kernel.org # v6.12+
Reported-by: Matt Fleming 
Closes: https://lore.kernel.org/all/20260601124156.2205704-1-mfleming@cloudflare.com/
Signed-off-by: Tejun Heo 
Reviewed-by: Andrea Righi 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

locking/rtmutex: Skip remove_waiter() when waiter is not enqueued

2026-06-19T11:48:05+00:00

commit 40a25d59e85b3c8709ac2424d44f65610467871e upstream.

syzbot triggered the following splat in remove_waiter() via
FUTEX_CMP_REQUEUE_PI:

  KASAN: null-ptr-deref in range [0x0000000000000a88-0x0000000000000a8f]
   class_raw_spinlock_constructor
   remove_waiter+0x159/0x1200 kernel/locking/rtmutex.c:1561
   rt_mutex_start_proxy_lock+0x103/0x120
   futex_requeue+0x10e4/0x20d0
   __x64_sys_futex+0x34f/0x4d0

task_blocks_on_rt_mutex() does not arm the waiter upon deadlock detection,
leaving waiter->task nil, where 3bfdc63936dd ("rtmutex: Use waiter::task instead
of current in remove_waiter()") made this fatal.

Furthermore, rt_mutex_start_proxy_lock() should not be calling into remove_waiter()
upon a successfully grabbing the rtmutex. 1a1fb985f2e2 ("futex: Handle early deadlock
return correctly"), moved the remove_waiter() out of __rt_mutex_start_proxy_lock()
(where 'ret' was only ever 0 or < 0) into the wrapper. Tighten this check to
account for try_to_take_rt_mutex().

Fixes: 3bfdc63936dd ("rtmutex: Use waiter::task instead of current in remove_waiter()")
Reported-by: syzbot+78147abe6c524f183ee9@syzkaller.appspotmail.com
Signed-off-by: Davidlohr Bueso 
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Closes: https://lore.kernel.org/all/69f114ac.050a0220.ac8b.0003.GAE@google.com/
Link: https://patch.msgid.link/20260507112913.1019537-1-dave@stgolabs.net
Signed-off-by: Greg Kroah-Hartman

futex/requeue: Prevent NULL pointer dereference in remove_waiter() on self-deadlock

2026-06-19T11:48:04+00:00

commit 74e144274af39935b0f410c0ee4d2b91c3730414 upstream.

When FUTEX_CMP_REQUEUE_PI requeues a non-top waiter that already owns the
target PI futex, task_blocks_on_rt_mutex() returns -EDEADLK before setting
waiter->task.

The subsequent remove_waiter() in rt_mutex_start_proxy_lock() dereferences
the NULL waiter->task, causing a kernel crash.

Add a self-deadlock check for non-top waiters before calling
rt_mutex_start_proxy_lock(), analogous to the top-waiter check in
futex_lock_pi_atomic().

Fixes: 3bfdc63936dd4773109b7b8c280c0f3b5ae7d349 ("rtmutex: Use waiter::task instead of current in remove_waiter()")
Signed-off-by: Ji'an Zhou 
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

pidfd: refuse access to tasks that have started exiting harder

2026-06-19T11:48:03+00:00

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) 
Signed-off-by: Greg Kroah-Hartman

timers/migration: Fix livelock in tmigr_handle_remote_up()

2026-06-19T11:48:02+00:00

commit d486b4934a8e504376b85cdb3766f306d57aff5b upstream.

tmigr_handle_remote_cpu() skips timer_expire_remote() when cpu ==
smp_processor_id(), assuming the local softirq path already handled this
CPU's timers.

This assumption is wrong because jiffies can advance after the handling of
the CPU's global timers in run_timer_base(BASE_GLOBAL) and before
tmigr_handle_remote() evaluates the expiry times.

As a consequence a timer which expires after the CPU local timer wheel
advanced and becomes expired in the remote handling is ignored and the
callback is never invoked and removed from the timer wheel.

What's worse is that fetch_next_timer_interrupt_remote() keeps reporting it
as expired, and the event is re-queued with expires == now on each
iteration.  The goto-again loop spins indefinitely.

Fix this by calling timer_expire_remote() unconditionally. That's minimal
overhead for the common case as __run_timer_base() returns immediately if
there is nothing to expire in the local wheel.

[ tglx: Amend change log and add a comment ]

Fixes: 7ee988770326 ("timers: Implement the hierarchical pull model")
Reported-by: Alon Kariv 
Signed-off-by: Amit Matityahu 
Signed-off-by: Thomas Gleixner 
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260603170139.33628-1-amitmat@amazon.com
Signed-off-by: Greg Kroah-Hartman

cgroup/cpuset: Use effective_xcpus in partcmd_update add/del mask calculation

2026-06-19T11:47:57+00:00

commit 0a68853de27b522bca2b9934127277185374a24f upstream.

When sibling CPU exclusion occurs, a partition's user_xcpus may contain
CPUs that were never actually granted to it. These CPUs are present in
user_xcpus(cs) but not in cs->effective_xcpus.

The partcmd_update path in update_parent_effective_cpumask() uses
user_xcpus(cs) (via the local variable xcpus) to compute the addmask
(CPUs to return to parent) and delmask (CPUs to request from parent).
This is incorrect:

 1) When newmask removes a CPU that was previously excluded by a
    sibling, addmask incorrectly includes that CPU and tries to return
    it to the parent even though the partition never actually owned it,
    causing CPU overlap with sibling partitions and triggering warnings
    in generate_sched_domains().

 2) When newmask adds a previously excluded CPU that is now available,
    delmask fails to request it from the parent because user_xcpus(cs)
    already includes it.

Fix this by using cs->effective_xcpus instead of user_xcpus(cs) in all
partcmd_update paths that calculate addmask or delmask, including the
PERR_NOCPUS error handling paths.

Reproducers:

  Example 1 - Removing a sibling-excluded CPU incorrectly returns it:

    # cd /sys/fs/cgroup
    # echo "0-1" > a1/cpuset.cpus
    # echo "root" > a1/cpuset.cpus.partition
    # echo "0-2" > b1/cpuset.cpus
    # echo "root" > b1/cpuset.cpus.partition
    # echo "2" > b1/cpuset.cpus
    # cat cpuset.cpus.effective
    # Actual: 0-1,3    Expected: 3

  Example 2 - Expanding to a previously excluded CPU fails to request it:

    # cd /sys/fs/cgroup
    # echo "0-1" > a1/cpuset.cpus
    # echo "root" > a1/cpuset.cpus.partition
    # echo "0-2" > b1/cpuset.cpus
    # echo "root" > b1/cpuset.cpus.partition
    # echo "member" > a1/cpuset.cpus.partition
    # echo "1-2" > b1/cpuset.cpus
    # cat cpuset.cpus.effective
    # Actual: 0-1,3    Expected: 0,3

Fixes: 2a3602030d80 ("cgroup/cpuset: Don't invalidate sibling partitions on cpuset.cpus conflict")
Cc: stable@vger.kernel.org # v7.0+
Suggested-by: Zhang Guopeng 
Signed-off-by: Sun Shaojie 
Reviewed-by: Waiman Long 
Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

tracing/probes: Point the error offset correctly for eprobe argument error

2026-06-19T11:47:57+00:00

commit 85e0f27dd1396307913ffc5745b0c05137e9beac upstream.

Fix to point the error offset correctly for eprobe argument error.
In the cleanup commit 1b8b0cd754cd ("tracing/probes: Move event parameter
fetching code to common parser"), due to incorrect backward compatibility
aimed at conforming to the test specifications, the error location was set
to 0 when a non-existent formal parameter was specified for Eprobe.
However, this should be corrected in both the test and the implementation
to point correct error position.

Link: https://lore.kernel.org/all/177967567399.209006.1451571244515632097.stgit@devnote2/

Fixes: 1b8b0cd754cd ("tracing/probes: Move event parameter fetching code to common parser")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) 
Reviewed-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

dma-debug: fix physical address retrieval in debug_dma_sync_sg_for_device

2026-06-19T11:47:49+00:00

[ Upstream commit 9bfaa86b405381326c971984fd6da184c289713f ]

In debug_dma_sync_sg_for_device(), when iterating over a scatterlist,
the debug entry population mistakenly uses the head of the scatterlist
'sg' to fetch the physical address via sg_phys(), instead of using the
current iterator variable 's'.

This causes dma-debug to track the physical address of the very first
scatterlist entry for all subsequent entries in the list.

Fix this by passing the correct loop iterator 's' to sg_phys()

Fixes: 9d4f645a1fd49ee ("dma-debug: store a phys_addr_t in struct dma_debug_entry")
Signed-off-by: Li RongQing 
Signed-off-by: Marek Szyprowski 
Link: https://lore.kernel.org/r/20260603123708.1665-1-lirongqing@baidu.com
Signed-off-by: Sasha Levin

dma-mapping: direct: fix missing mapping for THRU_HOST_BRIDGE segments

2026-06-19T11:47:49+00:00

[ Upstream commit 560000d619ef162568746ce287f0c725e24ea967 ]

In dma_direct_map_sg(), the case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE
incorrectly used 'break' instead of falling through to MAP_NONE.
As a result, segments traversing the host bridge skipped the required
dma_direct_map_phys() call entirely, leaving sg->dma_address
uninitialized and leading to DMA failures. Fix this by using
'fallthrough;'.

Fixes: a25e7962db0d79 ("PCI/P2PDMA: Refactor the p2pdma mapping helpers")
Reviewed-by: Logan Gunthorpe 
Signed-off-by: Li RongQing 
Signed-off-by: Marek Szyprowski 
Link: https://lore.kernel.org/r/20260603013723.2439-1-lirongqing@baidu.com
Signed-off-by: Sasha Levin

time: Fix off-by-one in settimeofday() usec validation

2026-06-19T11:47:48+00:00

[ 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 
Signed-off-by: Thomas Gleixner 
Acked-by: John Stultz 
Link: https://patch.msgid.link/4rikk44zew3s6577dugmx4jyblz7o5c57niuap6ct3td5yfm6w@gh7pcumg7qor
Signed-off-by: Sasha Levin