From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757989Ab0LBSrW (ORCPT ); Thu, 2 Dec 2010 13:47:22 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:35785 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757701Ab0LBSqr (ORCPT ); Thu, 2 Dec 2010 13:46:47 -0500 X-Authority-Analysis: v=1.1 cv=6ptpMFIBtxRk0xdOb6IhJTbTLVRlKjWFes7R4SsWCrA= c=1 sm=0 a=Sb8Y8iSdrvsA:10 a=bbbx4UPp9XUA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=1XWaLZrsAAAA:8 a=VwQbUJbxAAAA:8 a=meVymXHHAAAA:8 a=SSXtWKYvI7l3pPZqTPQA:9 a=XfJfwqs6nDMPXEFrWnfIfUaq2vAA:4 a=UTB_XpHje0EA:10 a=LI9Vle30uBYA:10 a=jeBq3FmKZ4MA:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Message-Id: <20101202184645.049700085@goodmis.org> User-Agent: quilt/0.48-1 Date: Thu, 02 Dec 2010 13:46:13 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Frederic Weisbecker , , Slava Pestov Subject: [PATCH 1/3] tracing: Fix panic when lseek() called on "trace" opened for writing References: <20101202184612.129218522@goodmis.org> Content-Disposition: inline; filename=0001-tracing-Fix-panic-when-lseek-called-on-trace-opened-.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Slava Pestov 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. Cc: Signed-off-by: Slava Pestov LKML-Reference: <1290640396-24179-1-git-send-email-slavapestov@google.com> Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 10 +++++++++- 1 files changed, 9 insertions(+), 1 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index ee6a733..21db0de 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2339,11 +2339,19 @@ tracing_write_stub(struct file *filp, const char __user *ubuf, return count; } +static loff_t tracing_seek(struct file *file, loff_t offset, int origin) +{ + if (file->f_mode & FMODE_READ) + return seq_lseek(file, offset, origin); + else + return 0; +} + static const struct file_operations tracing_fops = { .open = tracing_open, .read = seq_read, .write = tracing_write_stub, - .llseek = seq_lseek, + .llseek = tracing_seek, .release = tracing_release, }; -- 1.7.2.3