From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754102Ab1BOCB5 (ORCPT ); Mon, 14 Feb 2011 21:01:57 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.125]:63778 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754021Ab1BOCB4 (ORCPT ); Mon, 14 Feb 2011 21:01:56 -0500 X-Authority-Analysis: v=1.1 cv=dquaJDitHqzHCdqWSoZ6IgapSuTzW/4TaRYx9N9k4W8= c=1 sm=0 a=M7KJ_pm0K9UA:10 a=Q9fys5e9bTEA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=1XWaLZrsAAAA:8 a=mIxFq-LZL0PHU3xRJtEA:9 a=n086jQ4M3z1nIQOesVbm-g6kiawA:4 a=PUjeQqilurYA:10 a=UTB_XpHje0EA:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Subject: Re: [Stable-review] [PATCH 20/23] tracing: Fix panic when lseek() called on "trace" opened for writing From: Steven Rostedt To: Ben Hutchings Cc: Willy Tarreau , linux-kernel@vger.kernel.org, stable@kernel.org, stable-review@kernel.org, Slava Pestov , Greg Kroah-Hartman In-Reply-To: <1297733919.3104.126.camel@localhost> References: <20110206232253.378726212@pcw.home.local> <1297725267.3104.84.camel@localhost> <1297733613.23343.92.camel@gandalf.stny.rr.com> <1297733919.3104.126.camel@localhost> Content-Type: text/plain; charset="ISO-8859-15" Date: Mon, 14 Feb 2011 21:01:54 -0500 Message-ID: <1297735314.23343.94.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2011-02-15 at 01:38 +0000, Ben Hutchings wrote: > On Mon, 2011-02-14 at 20:33 -0500, Steven Rostedt wrote: > > On Mon, 2011-02-14 at 23:14 +0000, Ben Hutchings wrote: > > > On Mon, 2011-02-07 at 00:23 +0100, Willy Tarreau wrote: > > > > 2.6.27.58-stable review patch. If anyone has any objections, please let us know. > > > > > > > > ------------------ > > > > > > > > From: Slava Pestov > > > > > > > > commit 364829b1263b44aa60383824e4c1289d83d78ca7 upstream. > > > > > > > > The file_ops struct for the "trace" special file defined llseek as seq_lseek(). > > > > However, if the file was opened for writing only, seq_open() was not called, > > > > and the seek would dereference a null pointer, file->private_data. > > > > > > > > This patch introduces a new wrapper for seq_lseek() which checks if the file > > > > descriptor is opened for reading first. If not, it does nothing. > > > [...] > > > > --- longterm-2.6.27.orig/kernel/trace/trace.c 2011-01-23 10:52:37.000000000 +0100 > > > > +++ longterm-2.6.27/kernel/trace/trace.c 2011-01-29 11:42:07.287067215 +0100 > > > > @@ -2041,17 +2041,25 @@ > > > > return ret; > > > > } > > > > > > > > +static loff_t tracing_seek(struct file *file, loff_t offset, int origin) > > > [...] > > > > + .llseek = tracing_lseek, > > > [...] > > > > + .llseek = tracing_lseek, > > > [...] > > > > > > These names don't agree! > > > > What don't they agree on? > > Whether seek is spelt with an 'l'... Ah, I was looking at the two .llseek lines ;) Yeah, in mainline it's just tracing_seek. -- Steve