From: Ilya Dryomov <ilya.dryomov@inktank.com>
Date: Wed, 5 Feb 2014 13:19:55 +0000 (+0200)
Subject: libceph: do not dereference a NULL bio pointer
X-Git-Tag: v3.14-rc2~11^2
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=0ec1d15ec6ed513ab2cc86c67d94761d71228a32;p=uclinux-h8%2Flinux.git

libceph: do not dereference a NULL bio pointer

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>
Reviewed-by: Sage Weil <sage@inktank.com>
---

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);