Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762978AbZCTKbU (ORCPT ); Fri, 20 Mar 2009 06:31:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762681AbZCTK21 (ORCPT ); Fri, 20 Mar 2009 06:28:27 -0400 Received: from hera.kernel.org ([140.211.167.34]:35364 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761784AbZCTK2Z (ORCPT ); Fri, 20 Mar 2009 06:28:25 -0400 Date: Fri, 20 Mar 2009 10:26:44 GMT From: Li Zefan To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, acme@redhat.com, hpa@zytor.com, mingo@redhat.com, lizf@cn.fujitsu.com, jens.axboe@oracle.com, fweisbec@gmail.com, rostedt@goodmis.org, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, acme@redhat.com, linux-kernel@vger.kernel.org, lizf@cn.fujitsu.com, jens.axboe@oracle.com, fweisbec@gmail.com, rostedt@goodmis.org, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <49C30098.6080107@cn.fujitsu.com> References: <49C30098.6080107@cn.fujitsu.com> Subject: [tip:tracing/blktrace] blktrace: avoid accessing NULL bdev->bd_disk Message-ID: Git-Commit-ID: afaebb6720cc62df1b03e36c2f699b00cfee784e 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-4.0 (hera.kernel.org [127.0.0.1]); Fri, 20 Mar 2009 10:26:46 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2248 Lines: 73 Commit-ID: afaebb6720cc62df1b03e36c2f699b00cfee784e Gitweb: http://git.kernel.org/tip/afaebb6720cc62df1b03e36c2f699b00cfee784e Author: Li Zefan AuthorDate: Fri, 20 Mar 2009 10:34:00 +0800 Committer: Ingo Molnar CommitDate: Fri, 20 Mar 2009 11:20:07 +0100 blktrace: avoid accessing NULL bdev->bd_disk bdev->bd_disk can be NULL, if the block device is not opened. Try this against an unmounted partition, and you'll see NULL dereference: # echo 1 > /sys/block/sda/sda5/enable Signed-off-by: Li Zefan Cc: Jens Axboe Cc: Arnaldo Carvalho de Melo Cc: Steven Rostedt Acked-by: Frederic Weisbecker LKML-Reference: <49C30098.6080107@cn.fujitsu.com> Signed-off-by: Ingo Molnar --- kernel/trace/blktrace.c | 13 +++++++++++-- 1 files changed, 11 insertions(+), 2 deletions(-) diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index dfee6f9..108f4f7 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -1362,6 +1362,14 @@ static int blk_str2act_mask(const char *str) return mask; } +static struct request_queue *blk_trace_get_queue(struct block_device *bdev) +{ + if (bdev->bd_disk == NULL) + return NULL; + + return bdev_get_queue(bdev); +} + static ssize_t sysfs_blk_trace_attr_show(struct device *dev, struct device_attribute *attr, char *buf) @@ -1376,9 +1384,10 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev, if (bdev == NULL) goto out_unlock_kernel; - q = bdev_get_queue(bdev); + q = blk_trace_get_queue(bdev); if (q == NULL) goto out_bdput; + mutex_lock(&bdev->bd_mutex); if (attr == &dev_attr_enable) { @@ -1435,7 +1444,7 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev, if (bdev == NULL) goto out_unlock_kernel; - q = bdev_get_queue(bdev); + q = blk_trace_get_queue(bdev); if (q == NULL) goto out_bdput; -- 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/