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authorZqiang <qiang.zhang@windriver.com>2020-11-01 17:07:53 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-11-02 12:14:19 -0800
commit6993d0fdbee0eb38bfac350aa016f65ad11ed3b1 (patch)
treecad795370c775bae518a8a1fe2bdc35e1a4edb9e /kernel
parenta77eedbc871ee3b435bffc30b123b60eecca402c (diff)
kthread_worker: prevent queuing delayed work from timer_fn when it is being canceled
There is a small race window when a delayed work is being canceled and the work still might be queued from the timer_fn: CPU0 CPU1 kthread_cancel_delayed_work_sync() __kthread_cancel_work_sync() __kthread_cancel_work() work->canceling++; kthread_delayed_work_timer_fn() kthread_insert_work(); BUG: kthread_insert_work() should not get called when work->canceling is set. Signed-off-by: Zqiang <qiang.zhang@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20201014083030.16895-1-qiang.zhang@windriver.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kthread.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/kthread.c b/kernel/kthread.c
index e29773c82b70..933a625621b8 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -897,7 +897,8 @@ void kthread_delayed_work_timer_fn(struct timer_list *t)
/* Move the work from worker->delayed_work_list. */
WARN_ON_ONCE(list_empty(&work->node));
list_del_init(&work->node);
- kthread_insert_work(worker, work, &worker->work_list);
+ if (!work->canceling)
+ kthread_insert_work(worker, work, &worker->work_list);
raw_spin_unlock_irqrestore(&worker->lock, flags);
}