Skip to contentSkip to conversation

trace event block fix unassigned field

PATCH In review Mathieu Desnoyers 2 participants 3 messages Jan 6, 2011

Subsystems (2)
Tracing Device mapper
lore
Share & tools
lore

Mathieu Desnoyers

author reviewer
#0 lore raw

PATCH 1/1 trace event block fix unassigned field

The "error" field in block_bio_complete is not assigned, leaving the memory area uninitialized (keeping garbage data). Pass an additional tracepoint argument to this event to initialize this field.

From: Jeff Moyer <[email protected]>

Signed-off-by Jeff Moyer <[email protected]>
Signed-off-by Mathieu Desnoyers <[email protected]>
CC Steven Rostedt <[email protected]>
CC Frederic Weisbecker <[email protected]>
CC Ingo Molnar <[email protected]>
CC Thomas Gleixner <[email protected]>
CC Jens Axboe <[email protected]>
CC Li Zefan <[email protected]>
CC [email protected]
---
 drivers/md/dm.c              |    2 +-
 include/trace/events/block.h |    6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)
include/trace/events/block.h +4 -2
Index: linux-2.6-lttng/include/trace/events/block.h
===================================================================
@@ -206,15 +206,16 @@ TRACE_EVENT(block_bio_bounce,
  * block_bio_complete - completed all work on the block operation
  * @q: queue holding the block operation
  * @bio: block operation completed
+ * @error: io error value
  *
  * This tracepoint indicates there is no further work to do on this
  * block IO operation @bio.
  */
 TRACE_EVENT(block_bio_complete,
 
-	TP_PROTO(struct request_queue *q, struct bio *bio),
+	TP_PROTO(struct request_queue *q, struct bio *bio, int error),
 
-	TP_ARGS(q, bio),
+	TP_ARGS(q, bio, error),
 
 	TP_STRUCT__entry(
 		__field( dev_t,		dev		)

@@ -228,6 +229,7 @@ TRACE_EVENT(block_bio_complete,
 		__entry->dev		= bio->bi_bdev->bd_dev;
 		__entry->sector		= bio->bi_sector;
 		__entry->nr_sector	= bio->bi_size >> 9;
+		__entry->error		= error;
 		blk_fill_rwbs(__entry->rwbs, bio->bi_rw, bio->bi_size);
 	),
drivers/md/dm.c +1 -1
Index: linux-2.6-lttng/drivers/md/dm.c
===================================================================
@@ -659,7 +659,7 @@ static void dec_pending(struct dm_io *io
 			free_io(md, io);
 
 			if (io_error != DM_ENDIO_REQUEUE) {
-				trace_block_bio_complete(md->queue, bio);
+				trace_block_bio_complete(md->queue, bio, io_error);
 
 				bio_endio(bio, io_error);
 			}
Signature · 4 lines
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
#1 lore raw
Quoted 3 lines · Mathieu Desnoyers

The "error" field in block_bio_complete is not assigned, leaving the memory area uninitialized (keeping garbage data). Pass an additional tracepoint argument to this event to initialize this field.

Thanks guys, applied.

Signature · 1 line
Jens Axboe
author reviewer
#2 lore raw
Quoted 6 lines · * Jens Axboe ([email protected]) wrote:
Quoted 3 lines · Mathieu Desnoyers

The "error" field in block_bio_complete is not assigned, leaving the memory area uninitialized (keeping garbage data). Pass an additional tracepoint argument to this event to initialize this field.

Thanks guys, applied.

Thanks Jens. A side-note for Frederic and Steven: for this patch specifically, going through the block layer tree seems like the right approach, because we also modify the tracepoint caller code.

Thanks,

Mathieu

Signature · 4 lines
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com