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From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, linux-mm@kvack.org,
	mm-commits@vger.kernel.org, pmladek@suse.com,
	qiang.zhang@windriver.com, stable@vger.kernel.org, tj@kernel.org,
	torvalds@linux-foundation.org
Subject: [patch 10/15] kthread_worker: prevent queuing delayed work from timer_fn when it is being canceled
Date: Sun, 01 Nov 2020 17:07:53 -0800	[thread overview]
Message-ID: <20201102010753.nF453nOWt%akpm@linux-foundation.org> (raw)
In-Reply-To: <20201101170656.48abbd5e88375219f868af5e@linux-foundation.org>

From: Zqiang <qiang.zhang@windriver.com>
Subject: 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.

Link: https://lkml.kernel.org/r/20201014083030.16895-1-qiang.zhang@windriver.com
Signed-off-by: Zqiang <qiang.zhang@windriver.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/kthread.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/kernel/kthread.c~kthread_worker-prevent-queuing-delayed-work-from-timer_fn-when-it-is-being-canceled
+++ a/kernel/kthread.c
@@ -897,7 +897,8 @@ void kthread_delayed_work_timer_fn(struc
 	/* 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);
 }
_


  parent reply	other threads:[~2020-11-02  1:07 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-02  1:06 incoming Andrew Morton
2020-11-02  1:07 ` [patch 01/15] mm/mremap_pages: fix static key devmap_managed_key updates Andrew Morton
2020-11-02  1:07 ` [patch 02/15] hugetlb_cgroup: fix reservation accounting Andrew Morton
2020-11-02  1:07 ` [patch 03/15] mm: memcontrol: correct the NR_ANON_THPS counter of hierarchical memcg Andrew Morton
2020-11-02  1:07 ` [patch 04/15] mm: memcg: link page counters to root if use_hierarchy is false Andrew Morton
2020-11-02  1:07 ` [patch 05/15] kasan: adopt KUNIT tests to SW_TAGS mode Andrew Morton
2020-11-02  1:07 ` [patch 06/15] mm: mempolicy: fix potential pte_unmap_unlock pte error Andrew Morton
2020-11-02  1:07 ` [patch 07/15] ptrace: fix task_join_group_stop() for the case when current is traced Andrew Morton
2020-11-02  1:07 ` [patch 08/15] lib/crc32test: remove extra local_irq_disable/enable Andrew Morton
2020-11-02  1:07 ` [patch 09/15] mm/truncate.c: make __invalidate_mapping_pages() static Andrew Morton
2020-11-02  1:07 ` Andrew Morton [this message]
2020-11-02  1:07 ` [patch 11/15] mm, oom: keep oom_adj under or at upper limit when printing Andrew Morton
2020-11-02  1:08 ` [patch 12/15] mm: always have io_remap_pfn_range() set pgprot_decrypted() Andrew Morton
2020-11-02  1:08 ` [patch 13/15] epoll: check ep_events_available() upon timeout Andrew Morton
2020-11-02 17:08   ` Linus Torvalds
2020-11-02 17:48     ` Soheil Hassas Yeganeh
2020-11-02 18:51       ` Linus Torvalds
2020-11-02 19:38         ` Linus Torvalds
2020-11-02 19:54         ` Soheil Hassas Yeganeh
2020-11-02 20:12           ` Linus Torvalds
2020-11-02  1:08 ` [patch 14/15] epoll: add a selftest for epoll timeout race Andrew Morton
2020-11-02  1:08 ` [patch 15/15] kernel/hung_task.c: make type annotations consistent Andrew Morton

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