From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755439Ab0CDQbM (ORCPT ); Thu, 4 Mar 2010 11:31:12 -0500 Received: from hera.kernel.org ([140.211.167.34]:48384 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755241Ab0CDQbK (ORCPT ); Thu, 4 Mar 2010 11:31:10 -0500 Date: Thu, 4 Mar 2010 16:30:42 GMT From: tip-bot for Lai Jiangshan Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, rostedt@goodmis.org, tglx@linutronix.de, laijs@cn.fujitsu.com Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, rostedt@goodmis.org, tglx@linutronix.de, laijs@cn.fujitsu.com In-Reply-To: <4B8CE06A.9090207@cn.fujitsu.com> References: <4B8CE06A.9090207@cn.fujitsu.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:tracing/urgent] tracing: Fix warning in s_next of trace file ops Message-ID: Git-Commit-ID: ac91d85456372a90af5b85eb6620fd2efb1e431b 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]); Thu, 04 Mar 2010 16:30:43 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: ac91d85456372a90af5b85eb6620fd2efb1e431b Gitweb: http://git.kernel.org/tip/ac91d85456372a90af5b85eb6620fd2efb1e431b Author: Lai Jiangshan AuthorDate: Tue, 2 Mar 2010 17:54:50 +0800 Committer: Steven Rostedt CommitDate: Tue, 2 Mar 2010 21:11:47 -0500 tracing: Fix warning in s_next of trace file ops This warning in s_next() can be triggered by lseek(): [] ? s_next+0x77/0x80 [] warn_slowpath_common+0x81/0xa0 [] ? s_next+0x77/0x80 [] warn_slowpath_null+0x1a/0x20 [] s_next+0x77/0x80 [] traverse+0x117/0x200 [] seq_lseek+0xa3/0x120 [] ? seq_lseek+0x0/0x120 [] vfs_llseek+0x41/0x50 [] sys_llseek+0x66/0xa0 [] sysenter_do_call+0x12/0x26 The iterator "leftover" variable is zeroed in the opening of the trace file. But lseek can call s_start() which will call s_next() without reseting the "leftover" variable back to zero, which might trigger the WARN_ON_ONCE(iter->leftover) that is in s_next(). Cc: stable@kernel.org Signed-off-by: Lai Jiangshan LKML-Reference: <4B8CE06A.9090207@cn.fujitsu.com> Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 032c57c..5edf410 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1703,6 +1703,7 @@ static void *s_start(struct seq_file *m, loff_t *pos) ftrace_enable_cpu(); + iter->leftover = 0; for (p = iter; p && l < *pos; p = s_next(m, p, &l)) ;