Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933138Ab0LUA4D (ORCPT ); Mon, 20 Dec 2010 19:56:03 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:58921 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S932628Ab0LUA4B (ORCPT ); Mon, 20 Dec 2010 19:56:01 -0500 Message-ID: <4D0FFB1A.7070407@cn.fujitsu.com> Date: Tue, 21 Dec 2010 08:55:54 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1b3pre) Gecko/20090513 Fedora/3.0-2.3.beta2.fc11 Thunderbird/3.0b2 MIME-Version: 1.0 To: Steven Rostedt CC: Frederic Weisbecker , Jiri Olsa , LKML , Hiroyuki KAMEZAWA Subject: Re: [PATCH] tracing: Fix preempt count leak References: <4D0089AC.1020802@cn.fujitsu.com> In-Reply-To: <4D0089AC.1020802@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2010-12-21 08:55:47, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2010-12-21 08:55:49, Serialize complete at 2010-12-21 08:55:49 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1596 Lines: 50 Any comment? 15:47, Li Zefan wrote: > While running my ftrace stress test, this showed up: > > BUG: sleeping function called from invalid context at mm/mmap.c:233 > ... > note: cat[3293] exited with preempt_count 1 > > The bug was introduced by commit 91e86e560d0b3ce4c5fc64fd2bbb99f856a30a4e > ("tracing: Fix recursive user stack trace") > > Signed-off-by: Li Zefan > --- > kernel/trace/trace.c | 6 ++---- > 1 files changed, 2 insertions(+), 4 deletions(-) > > diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c > index c380612..5767457 100644 > --- a/kernel/trace/trace.c > +++ b/kernel/trace/trace.c > @@ -1313,12 +1313,10 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) > > __this_cpu_inc(user_stack_count); > > - > - > event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK, > sizeof(*entry), flags, pc); > if (!event) > - return; > + goto out_drop_count; > entry = ring_buffer_event_data(event); > > entry->tgid = current->tgid; > @@ -1333,8 +1331,8 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc) > if (!filter_check_discard(call, entry, buffer, event)) > ring_buffer_unlock_commit(buffer, event); > > + out_drop_count: > __this_cpu_dec(user_stack_count); > - > out: > preempt_enable(); > } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/