From patchwork Mon Nov 26 16:57:17 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [147/270] libceph: avoid NULL kref_put when osd reset races with alloc_msg Date: Mon, 26 Nov 2012 06:57:17 -0000 From: Herton Ronaldo Krzesinski X-Patchwork-Id: 201881 Message-Id: <1353949160-26803-148-git-send-email-herton.krzesinski@canonical.com> To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Sage Weil 3.5.7u1 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Sage Weil commit 9bd952615a42d7e2ce3fa2c632e808e804637a1a upstream. The ceph_on_in_msg_alloc() method drops con->mutex while it allocates a message. If that races with a timeout that resends a zillion messages and resets the connection, and the ->alloc_msg() method returns a NULL message, it will call ceph_msg_put(NULL) and BUG. Fix by only calling put if msg is non-NULL. Fixes http://tracker.newdream.net/issues/3142 Signed-off-by: Sage Weil Signed-off-by: Herton Ronaldo Krzesinski --- net/ceph/messenger.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index 0de041f..692243a 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -2746,7 +2746,8 @@ static int ceph_con_in_msg_alloc(struct ceph_connection *con, int *skip) msg = con->ops->alloc_msg(con, hdr, skip); mutex_lock(&con->mutex); if (con->state != CON_STATE_OPEN) { - ceph_msg_put(msg); + if (msg) + ceph_msg_put(msg); return -EAGAIN; } con->in_msg = msg;