From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758055Ab2IZRVw (ORCPT ); Wed, 26 Sep 2012 13:21:52 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:10407 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1756607Ab2IZRSm (ORCPT ); Wed, 26 Sep 2012 13:18:42 -0400 X-IronPort-AV: E=Sophos;i="4.80,492,1344182400"; d="scan'208";a="5922247" From: Lai Jiangshan To: Tejun Heo , linux-kernel@vger.kernel.org Cc: Lai Jiangshan , tangchen , Ingo Molnar , Peter Zijlstra Subject: [PATCH 02/12] workqueue: disallow set_cpus_allowed_ptr() from work item Date: Thu, 27 Sep 2012 01:20:33 +0800 Message-Id: <1348680043-5077-3-git-send-email-laijs@cn.fujitsu.com> X-Mailer: git-send-email 1.7.4.4 In-Reply-To: <1348680043-5077-1-git-send-email-laijs@cn.fujitsu.com> References: <1348680043-5077-1-git-send-email-laijs@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/09/27 01:18:45, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/09/27 01:18:45, Serialize complete at 2012/09/27 01:18:45 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org workers depend on local-wake-up, if a work function change its CPU, it will corrupt workqueue, disallow this behavior. When set_cpus_allowed_ptr() is called from workqueue.c in worker_thread(), we clear the PF_WQ_WORKER before set_cpus_allowed_ptr() and set it back after. (rescuer thread has no PF_WQ_WORKER, skip this behavior) It prevents other/future BUGs like https://bugzilla.kernel.org/show_bug.cgi?id=47301. CC: tangchen Signed-off-by: Lai Jiangshan --- kernel/sched/core.c | 8 +++++--- kernel/workqueue.c | 10 +++++++++- 2 files changed, 14 insertions(+), 4 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index d325c4b..355d3cc 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5187,9 +5187,11 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) goto out; } - if (unlikely((p->flags & PF_THREAD_BOUND) && p != current)) { - ret = -EINVAL; - goto out; + if (unlikely(p->flags & PF_THREAD_BOUND)) { + if (WARN_ON_ONCE(p->flags & PF_WQ_WORKER) || p != current) { + ret = -EINVAL; + goto out; + } } do_set_cpus_allowed(p, new_mask); diff --git a/kernel/workqueue.c b/kernel/workqueue.c index ec882a6..c55884d 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1600,6 +1600,7 @@ __acquires(&gcwq->lock) struct global_cwq *gcwq = worker->pool->gcwq; struct task_struct *task = worker->task; + BUG_ON(task != current); while (true) { /* * The following call may fail, succeed or succeed @@ -1607,9 +1608,16 @@ __acquires(&gcwq->lock) * it races with cpu hotunplug operation. Verify * against GCWQ_DISASSOCIATED. */ - if (!(gcwq->flags & GCWQ_DISASSOCIATED)) + if (!(gcwq->flags & GCWQ_DISASSOCIATED)) { + if (!(worker->flags & WORKER_RESCUER)) + task->flags &= ~PF_WQ_WORKER; + set_cpus_allowed_ptr(task, get_cpu_mask(gcwq->cpu)); + if (!(worker->flags & WORKER_RESCUER)) + task->flags |= PF_WQ_WORKER; + } + spin_lock_irq(&gcwq->lock); if (gcwq->flags & GCWQ_DISASSOCIATED) return false; -- 1.7.7.6