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| author | Li Zefan <lizf@cn.fujitsu.com> | 2009-03-20 03:34:00 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-03-21 16:17:24 +0100 |
| commit | b125130b22d67f249beba10b71a254558b5279d0 (patch) | |
| tree | f42f4f732a2d7920009f34d798d1803def38ea44 /kernel/trace/blktrace.c | |
| parent | blktrace: remove sysfs_blk_trace_enable_show/store() (diff) | |
| download | linux-b125130b22d67f249beba10b71a254558b5279d0.tar.xz linux-b125130b22d67f249beba10b71a254558b5279d0.zip | |
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 <lizf@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <49C30098.6080107@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace/blktrace.c')
| -rw-r--r-- | 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 dfee6f915179..108f4f7715a5 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; |