diff options
| author | Frederic Weisbecker <frederic@kernel.org> | 2024-09-13 23:46:34 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-10-09 12:47:19 -0700 |
| commit | 214e01ad4ed7158cab66498810094fac5d09b218 (patch) | |
| tree | 4bc026aea1ddf33d5653ae0fb2d0ed524b25156b /kernel | |
| parent | 9a8da05d7ad619beb84d0c6904c3fa7022c6fb9b (diff) | |
kthread: unpark only parked kthread
Calling into kthread unparking unconditionally is mostly harmless when
the kthread is already unparked. The wake up is then simply ignored
because the target is not in TASK_PARKED state.
However if the kthread is per CPU, the wake up is preceded by a call
to kthread_bind() which expects the task to be inactive and in
TASK_PARKED state, which obviously isn't the case if it is unparked.
As a result, calling kthread_stop() on an unparked per-cpu kthread
triggers such a warning:
WARNING: CPU: 0 PID: 11 at kernel/kthread.c:525 __kthread_bind_mask kernel/kthread.c:525
<TASK>
kthread_stop+0x17a/0x630 kernel/kthread.c:707
destroy_workqueue+0x136/0xc40 kernel/workqueue.c:5810
wg_destruct+0x1e2/0x2e0 drivers/net/wireguard/device.c:257
netdev_run_todo+0xe1a/0x1000 net/core/dev.c:10693
default_device_exit_batch+0xa14/0xa90 net/core/dev.c:11769
ops_exit_list net/core/net_namespace.c:178 [inline]
cleanup_net+0x89d/0xcc0 net/core/net_namespace.c:640
process_one_work kernel/workqueue.c:3231 [inline]
process_scheduled_works+0xa2c/0x1830 kernel/workqueue.c:3312
worker_thread+0x86d/0xd70 kernel/workqueue.c:3393
kthread+0x2f0/0x390 kernel/kthread.c:389
ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
Fix this with skipping unecessary unparking while stopping a kthread.
Link: https://lkml.kernel.org/r/20240913214634.12557-1-frederic@kernel.org
Fixes: 5c25b5ff89f0 ("workqueue: Tag bound workers with KTHREAD_IS_PER_CPU")
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reported-by: syzbot+943d34fa3cf2191e3068@syzkaller.appspotmail.com
Tested-by: syzbot+943d34fa3cf2191e3068@syzkaller.appspotmail.com
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/kthread.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c index db4ceb0f503c..9bb36897b6c6 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -623,6 +623,8 @@ void kthread_unpark(struct task_struct *k) { struct kthread *kthread = to_kthread(k); + if (!test_bit(KTHREAD_SHOULD_PARK, &kthread->flags)) + return; /* * Newly created kthread was parked when the CPU was offline. * The binding was lost and we need to set it again. |