From: Olaf Kirch <olaf.kirch@oracle.com>
Date: Wed, 9 May 2007 09:32:52 +0000 (-0700)
Subject: dm crypt: fix avoid cloned bio ref after free
X-Git-Tag: v2.6.22-rc1~310
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=98221eb757de03d9aa6262b1eded2be708640ccc;p=linux-2.6

dm crypt: fix avoid cloned bio ref after free

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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index db439363f9..1dc2c62200 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);
 	}
 }