3.13-stable review patch. If anyone has any objections, please let me know.
------------------ From: Ilya Dryomov <[email protected]> commit f2be82b0058e90b5d9ac2cb896b4914276fb50ef upstream. 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 <[email protected]> Reviewed-by: Sage Weil <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- net/ceph/messenger.c | 3 +-- net/ceph/osd_client.c | 4 ++-- 2 files changed, 3 insertions(+), 4 deletions(-) --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -3126,7 +3126,6 @@ struct ceph_msg *ceph_msg_new(int type, INIT_LIST_HEAD(&m->data); /* front */ - m->front_alloc_len = front_len; if (front_len) { if (front_len > PAGE_CACHE_SIZE) { m->front.iov_base = __vmalloc(front_len, flags, @@ -3143,7 +3142,7 @@ struct ceph_msg *ceph_msg_new(int type, } else { m->front.iov_base = NULL; } - m->front.iov_len = front_len; + m->front_alloc_len = m->front.iov_len = front_len; dout("ceph_msg_new %p front %d\n", m, front_len); return m; --- a/net/ceph/osd_client.c +++ b/net/ceph/osd_client.c @@ -2515,9 +2515,9 @@ static struct ceph_msg *get_reply(struct 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, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
