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authorSage Weil <sage@inktank.com>2012-10-25 08:49:41 -0700
committerAlex Elder <elder@inktank.com>2012-10-26 16:35:04 -0500
commit7246240c7c186542f73af4fadc744d66440f616f (patch)
tree2b6270df2edae0dcc6e7c7c3474ff9c46d841e55
parent0f9831a89310cebba52d3f526e6cc5c2e403e6f1 (diff)
libceph: avoid NULL kref_put from NULL alloc_msg return
The ceph_on_in_msg_alloc() method calls the ->alloc_msg() helper which may return NULL. It also drops con->mutex while it allocates a message, which means that the connection state may change (e.g., get closed). If that happens, we clean up and bail out. Avoid calling ceph_msg_put() on a NULL return value and triggering a crash. This was observed when an ->alloc_msg() call races with a timeout that resends a zillion messages and resets the connection, and ->alloc_msg() returns NULL (because the request was resent to another target). Fixes http://tracker.newdream.net/issues/3342 Signed-off-by: Sage Weil <sage@inktank.com> Reviewed-by: Alex Elder <elder@inktank.com>
-rw-r--r--net/ceph/messenger.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 66f6f56bcb2..1041114453d 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -2742,7 +2742,8 @@ 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;