From: Tejun Heo <tj@kernel.org>
To: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 15/21] workqueue: remove worker_maybe_bind_and_lock()
Date: Wed, 20 Mar 2013 11:10:10 -0700 [thread overview]
Message-ID: <20130320181010.GA30484@htj.dyndns.org> (raw)
In-Reply-To: <1363721306-2030-16-git-send-email-laijs@cn.fujitsu.com>
On Wed, Mar 20, 2013 at 03:28:15AM +0800, Lai Jiangshan wrote:
> static struct worker *alloc_worker(void)
> {
> struct worker *worker;
> @@ -2326,7 +2262,8 @@ repeat:
> spin_unlock_irq(&wq_mayday_lock);
>
> /* migrate to the target cpu if possible */
> - worker_maybe_bind_and_lock(pool);
> + set_cpus_allowed_ptr(current, pool->attrs->cpumask);
> + spin_lock_irq(&pool->lock);
> rescuer->pool = pool;
You can't do this. The CPU might go up between set_cpus_allowed_ptr()
and spin_lock_irq() and the rescuer can end up executing a work item
which was issued while the target CPU is up on the wrong CPU.
Thanks.
--
tejun
next prev parent reply other threads:[~2013-03-20 18:10 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-19 19:28 [PATCH 00/21] workqueue: cleanups and better locking for recent changes Lai Jiangshan
2013-03-19 19:28 ` [PATCH 01/21] workqueue: add missing POOL_FREEZING Lai Jiangshan
2013-03-20 17:18 ` Tejun Heo
2013-03-20 17:24 ` Tejun Heo
2013-03-19 19:28 ` [PATCH 02/21] workqueue: don't free pool->worker_idr by RCU Lai Jiangshan
2013-03-20 17:29 ` Tejun Heo
2013-03-19 19:28 ` [PATCH 03/21] workqueue: simplify current_is_workqueue_rescuer() Lai Jiangshan
2013-03-20 17:33 ` Tejun Heo
2013-03-19 19:28 ` [PATCH 04/21] workqueue: swap the two branches in pwq_adjust_max_active() to get better readability Lai Jiangshan
2013-03-20 17:39 ` Tejun Heo
2013-03-19 19:28 ` [PATCH 05/21] workqueue: kick workers in pwq_adjust_max_active() Lai Jiangshan
2013-03-20 17:56 ` [PATCH] workqueue: kick a worker " Tejun Heo
2013-03-19 19:28 ` [PATCH 06/21] workqueue: separate out pools locking into pools_mutex Lai Jiangshan
2013-03-20 17:58 ` Tejun Heo
2013-03-19 19:28 ` [PATCH 07/21] workqueue: rename wq_mutex to wqs_mutex Lai Jiangshan
2013-03-19 19:28 ` [PATCH 08/21] workqueue: rename wq->flush_mutex to wq->mutex Lai Jiangshan
2013-03-19 19:28 ` [PATCH 09/21] workqueue: use wq->mutex to protects ->nr_drainers and __WQ_DRAINING Lai Jiangshan
2013-03-19 19:28 ` [PATCH 10/21] workqueue: use rcu_read_lock_sched() instead for accessing pwq in RCU Lai Jiangshan
2013-03-20 18:01 ` Tejun Heo
2013-03-19 19:28 ` [PATCH 11/21] workqueue: also allowed wq->mutex protect for_each_pwq() Lai Jiangshan
2013-03-19 19:28 ` [PATCH 12/21] workqueue: use wq->mutex to protect saved_max_active Lai Jiangshan
2013-03-19 19:28 ` [PATCH 13/21] workqueue: remove unused pwq_lock Lai Jiangshan
2013-03-19 19:28 ` [PATCH 14/21] workqueue: add wq->freezing and remove POOL_FREEZING Lai Jiangshan
2013-03-19 19:28 ` [PATCH 15/21] workqueue: remove worker_maybe_bind_and_lock() Lai Jiangshan
2013-03-20 18:10 ` Tejun Heo [this message]
2013-03-21 11:03 ` Lai Jiangshan
2013-03-21 17:41 ` Tejun Heo
2013-03-19 19:28 ` [PATCH 16/21] workqueue: rename rebind_workers() to associate_cpu_pool() Lai Jiangshan
2013-03-19 19:28 ` [PATCH 17/21] workqueue: simplify workqueue_cpu_up_callback(CPU_ONLINE) Lai Jiangshan
2013-03-20 18:16 ` Tejun Heo
2013-03-19 19:28 ` [PATCH 18/21] workqueue: read POOL_DISASSOCIATED bit under pool->lock Lai Jiangshan
2013-03-20 18:19 ` Tejun Heo
2013-03-19 19:28 ` [PATCH 19/21] workqueue: remove @p_last_pwq from init_and_link_pwq() Lai Jiangshan
2013-03-19 19:28 ` [PATCH 20/21] workqueue: modify wq->freezing only when freezable Lai Jiangshan
2013-03-19 19:28 ` [PATCH 21/21] workqueue: avoid false negative in assert_manager_or_pool_lock() Lai Jiangshan
2013-03-20 18:22 ` Tejun Heo
2013-03-20 16:38 ` [PATCH 00/21] workqueue: cleanups and better locking for recent changes Lai Jiangshan
2013-03-20 16:40 ` Tejun Heo
2013-03-20 18:30 ` Tejun Heo
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