workqueue: fix max_active handling in init_and_link_pwq() (983ca25e) · Commits · 戴 / test

Since ("workqueue: implement apply_workqueue_attrs()"), init_and_link_pwq() may be called to initialize a new pool_workqueue for a workqueue which is already online, but the function was setting pwq->max_active to wq->saved_max_active without proper synchronization. Fix it by calling pwq_adjust_max_active() under proper locking instead of manually setting max_active. Signed-off-by:

Tejun Heo <tj@kernel.org>

kernel/workqueue.c

+9 −5

Original line number	Diff line number	Diff line
		@@ -3771,21 +3771,25 @@ static void init_and_link_pwq(struct pool_workqueue *pwq,
		pwq->wq = wq;
		pwq->flush_color = -1;
		pwq->refcnt = 1;
		pwq->max_active = wq->saved_max_active;
		INIT_LIST_HEAD(&pwq->delayed_works);
		INIT_LIST_HEAD(&pwq->mayday_node);
		INIT_WORK(&pwq->unbound_release_work, pwq_unbound_release_workfn);

		/*
		* Link @pwq and set the matching work_color. This is synchronized
		* with flush_mutex to avoid confusing flush_workqueue().
		*/
		mutex_lock(&wq->flush_mutex);
		spin_lock_irq(&workqueue_lock);

		/*
		* Set the matching work_color. This is synchronized with
		* flush_mutex to avoid confusing flush_workqueue().
		*/
		if (p_last_pwq)
		*p_last_pwq = first_pwq(wq);
		pwq->work_color = wq->work_color;

		/* sync max_active to the current setting */
		pwq_adjust_max_active(pwq);

		/* link in @pwq */
		list_add_rcu(&pwq->pwqs_node, &wq->pwqs);

		spin_unlock_irq(&workqueue_lock);

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