From: Olaf Kirch <olaf.kirch@oracle.com>

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@oracle.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/md/dm-crypt.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletion(-)

diff -puN drivers/md/dm-crypt.c~dm-crypt-fix-avoid-cloned-bio-ref-after-free drivers/md/dm-crypt.c
--- a/drivers/md/dm-crypt.c~dm-crypt-fix-avoid-cloned-bio-ref-after-free
+++ a/drivers/md/dm-crypt.c
@@ -655,9 +655,12 @@ static void process_write(struct crypt_i
 
 		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);
 	}
 }
 
_