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authorCarsten Emde <Carsten.Emde@osadl.org>2009-09-12 00:05:37 +0200
committerSteven Rostedt <rostedt@goodmis.org>2009-09-12 21:31:19 -0400
commitfe63b94a430c0c8058de317f0a8ce921c69dbee4 (patch)
tree113a32a157b4629e7ca37debdc0cdc59a4c11e52 /include/trace/events/block.h
parent689fd8b65d669b96d612ccc37d6fb87bf7ed6907 (diff)
downloadvexpress-lsk-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>
Diffstat (limited to 'include/trace/events/block.h')
-rw-r--r--include/trace/events/block.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/include/trace/events/block.h b/include/trace/events/block.h
index 9a74b468a22..d86af94691c 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);