libceph: fix preallocation check in get_reply()
The check that makes sure that we have enough memory allocated to read
in the entire header of the message in question is currently busted.
It compares front_len of the incoming message with iov_len field of
ceph_msg::front structure, which is used primarily to indicate the
amount of data already read in, and not the size of the allocated
buffer. Under certain conditions (e.g. a short read from a socket
followed by that socket's shutdown and owning ceph_connection reset)
this results in a warning similar to
[85688.975866] libceph: get_reply front 198 > preallocated 122 (4#0)
and, through another bug, leads to forever hung tasks and forced
reboots. Fix this by comparing front_len with front_alloc_len field of
struct ceph_msg, which stores the actual size of the buffer.
Fixes: http://tracker.ceph.com/issues/5425
Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 7619c37..7331951 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -2522,9 +2522,9 @@
req->r_reply, req->r_reply->con);
ceph_msg_revoke_incoming(req->r_reply);
- if (front_len > req->r_reply->front.iov_len) {
+ if (front_len > req->r_reply->front_alloc_len) {
pr_warning("get_reply front %d > preallocated %d (%u#%llu)\n",
- front_len, (int)req->r_reply->front.iov_len,
+ front_len, req->r_reply->front_alloc_len,
(unsigned int)con->peer_name.type,
le64_to_cpu(con->peer_name.num));
m = ceph_msg_new(CEPH_MSG_OSD_OPREPLY, front_len, GFP_NOFS,