Messages in this thread | | | Date | Wed, 19 Feb 2014 19:11:42 -0500 | From | Tejun Heo <> | Subject | Re: [PATCH] workqueue: Fix possible unexpectedly worker wakeup before started |
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Hello, Lai.
On Wed, Feb 19, 2014 at 11:47:58AM +0800, Lai Jiangshan wrote: > If a worker is wokenup unexpectedly, it will start to work incorretly. > Although it hardly happen, we should catch it and wait for being started > if it does happen.
Can this actually happen? If so, how?
> Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> > --- > kernel/workqueue.c | 6 ++++++ > 1 files changed, 6 insertions(+), 0 deletions(-) > > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index 82ef9f3..bee5fe1 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -2284,6 +2284,12 @@ static int worker_thread(void *__worker) > struct worker *worker = __worker; > struct worker_pool *pool = worker->pool; > > + if (WARN_ON_ONCE(!(worker->flags & WORKER_STARTED))) {
And if this is something which can legitimately happen, why are we triggering WARN on it?
> + /* The worker is wokenup unexpectedly before started */ > + mutex_lock(&pool->manager_mutex); > + mutex_unlock(&pool->manager_mutex);
And what does these mutex cycling achieve (they need comment)?
Thanks.
-- tejun
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