[2.6.20.16 review 17/28] dm crypt: fix avoid cloned bio ref after free

[Willy Tarreau]

Do not access the bio after generic_make_request

We should never access a bio after generic_make_request - there's no guarantee
it still exists.

Signed-off-by: Olaf Kirch <olaf.kirch@xxxxxxxxxx>
Signed-off-by: Alasdair G Kergon <agk@xxxxxxxxxx>
Cc: Jens Axboe <jens.axboe@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 drivers/md/dm-crypt.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index bffaf1c..28831a9 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -655,9 +655,12 @@ static void process_write(struct crypt_io *io)
 
 		generic_make_request(clone);
 
+		/* Do not reference clone after this - it
+		 * may be gone already. */
+
 		/* out of memory -> run queues */
 		if (remaining)
-			congestion_wait(bio_data_dir(clone), HZ/100);
+			congestion_wait(WRITE, HZ/100);
 	}
 }
 
-- 
1.5.2.4

-- 
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