diff options
| author | Carsten Emde <Carsten.Emde@osadl.org> | 2009-09-12 00:05:37 +0200 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2009-09-12 21:31:19 -0400 |
| commit | fe63b94a430c0c8058de317f0a8ce921c69dbee4 (patch) | |
| tree | 113a32a157b4629e7ca37debdc0cdc59a4c11e52 | |
| parent | 689fd8b65d669b96d612ccc37d6fb87bf7ed6907 (diff) | |
| download | linux-fe63b94a430c0c8058de317f0a8ce921c69dbee4.tar.gz | |
tracing: prevent NULL pointer dereference in ftrace_raw_event_block_bio_bounce
Booting 2.6.31 and executing
echo 1 >/sys/kernel/debug/tracing/events/enable
leads to
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<c032a583>] ftrace_raw_event_block_bio_bounce+0x4b/0xb9
Apparently,
bio = bio_map_user(q, NULL, uaddr, len, reading, gfp_mask);
is called in block/blk-map.c:58 where bio->bi_bdev in set to NULL and
still is NULL when an attempt is made to evaluate bio->bi_bdev->bd_dev
in include/trace/events/block.h:189.
The tracepoint should ensure bio->bi_bdev is not dereferenced, if NULL.
Signed-off-by: Carsten Emde <C.Emde@osadl.org>
LKML-Reference: <4AAAC9B1.9060505@osadl.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| -rw-r--r-- | include/trace/events/block.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/include/trace/events/block.h b/include/trace/events/block.h index 9a74b468a229..d86af94691c2 100644 --- a/include/trace/events/block.h +++ b/include/trace/events/block.h @@ -171,6 +171,7 @@ TRACE_EVENT(block_rq_complete, (unsigned long long)__entry->sector, __entry->nr_sector, __entry->errors) ); + TRACE_EVENT(block_bio_bounce, TP_PROTO(struct request_queue *q, struct bio *bio), @@ -186,7 +187,8 @@ TRACE_EVENT(block_bio_bounce, ), TP_fast_assign( - __entry->dev = bio->bi_bdev->bd_dev; + __entry->dev = bio->bi_bdev ? + bio->bi_bdev->bd_dev : 0; __entry->sector = bio->bi_sector; __entry->nr_sector = bio->bi_size >> 9; blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size); |