From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754440Ab0DBTIZ (ORCPT ); Fri, 2 Apr 2010 15:08:25 -0400 Received: from hera.kernel.org ([140.211.167.34]:47824 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753778Ab0DBTIS (ORCPT ); Fri, 2 Apr 2010 15:08:18 -0400 Date: Fri, 2 Apr 2010 19:07:46 GMT From: tip-bot for Mike Galbraith Cc: linux-kernel@vger.kernel.org, acme@redhat.com, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, lizf@cn.fujitsu.com, efault@gmx.de, fweisbec@gmail.com, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, acme@redhat.com, linux-kernel@vger.kernel.org, fweisbec@gmail.com, lizf@cn.fujitsu.com, a.p.zijlstra@chello.nl, efault@gmx.de, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <1269598293.6174.8.camel@marge.simson.net> References: <1269598293.6174.8.camel@marge.simson.net> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf: Fix 'perf sched record' deadlock Message-ID: Git-Commit-ID: 8bb39f9aa068262732fe44b965d7a6eb5a5a7d67 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Fri, 02 Apr 2010 19:07:47 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 8bb39f9aa068262732fe44b965d7a6eb5a5a7d67 Gitweb: http://git.kernel.org/tip/8bb39f9aa068262732fe44b965d7a6eb5a5a7d67 Author: Mike Galbraith AuthorDate: Fri, 26 Mar 2010 11:11:33 +0100 Committer: Ingo Molnar CommitDate: Fri, 2 Apr 2010 19:30:05 +0200 perf: Fix 'perf sched record' deadlock perf sched record can deadlock a box should the holder of handle->data->lock take an interrupt, and then attempt to acquire an rq lock held by a CPU trying to acquire the same lock. Disable interrupts. CPU0 CPU1 sched event with rq->lock held grab handle->data->lock spin on handle->data->lock interrupt try to grab rq->lock Reported-by: Li Zefan Signed-off-by: Mike Galbraith Tested-by: Li Zefan Signed-off-by: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker LKML-Reference: <1269598293.6174.8.camel@marge.simson.net> Signed-off-by: Ingo Molnar --- kernel/perf_event.c | 15 ++++++++++++--- 1 files changed, 12 insertions(+), 3 deletions(-) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index b0feb47..96aae13 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -3376,15 +3376,23 @@ static void perf_event_task_output(struct perf_event *event, struct perf_task_event *task_event) { struct perf_output_handle handle; - int size; struct task_struct *task = task_event->task; - int ret; + unsigned long flags; + int size, ret; + + /* + * If this CPU attempts to acquire an rq lock held by a CPU spinning + * in perf_output_lock() from interrupt context, it's game over. + */ + local_irq_save(flags); size = task_event->event_id.header.size; ret = perf_output_begin(&handle, event, size, 0, 0); - if (ret) + if (ret) { + local_irq_restore(flags); return; + } task_event->event_id.pid = perf_event_pid(event, task); task_event->event_id.ppid = perf_event_pid(event, current); @@ -3395,6 +3403,7 @@ static void perf_event_task_output(struct perf_event *event, perf_output_put(&handle, task_event->event_id); perf_output_end(&handle); + local_irq_restore(flags); } static int perf_event_task_match(struct perf_event *event)