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libceph: do not dereference a NULL bio pointer

Message ID 1391608063-5744-1-git-send-email-ilya.dryomov@inktank.com (mailing list archive)
State New, archived
Headers show

Commit Message

Ilya Dryomov Feb. 5, 2014, 1:47 p.m. UTC 
Commit f38a5181d9f3 ("ceph: Convert to immutable biovecs") introduced
a NULL pointer dereference, which broke rbd in -rc1.  Fix it.

Cc: Kent Overstreet <kmo@daterainc.com>
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
---
 net/ceph/messenger.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
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Patch

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 0e478a0f4204..30efc5c18622 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -840,9 +840,13 @@  static bool ceph_msg_data_bio_advance(struct ceph_msg_data_cursor *cursor,
 
 	if (!cursor->bvec_iter.bi_size) {
 		bio = bio->bi_next;
-		cursor->bvec_iter = bio->bi_iter;
+		cursor->bio = bio;
+		if (bio)
+			cursor->bvec_iter = bio->bi_iter;
+		else
+			memset(&cursor->bvec_iter, 0,
+			       sizeof(cursor->bvec_iter));
 	}
-	cursor->bio = bio;
 
 	if (!cursor->last_piece) {
 		BUG_ON(!cursor->resid);