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 <[email protected]>
Acked-by: Frederic Weisbecker <[email protected]>
Acked-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Steven Rostedt <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions