Merge tag 'rxrpc-fixes-20200203' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

David Howells says:

====================
RxRPC fixes

Here are a number of fixes for AF_RXRPC:

 (1) Fix a potential use after free in rxrpc_put_local() where it was
     accessing the object just put to get tracing information.

 (2) Fix insufficient notifications being generated by the function that
     queues data packets on a call.  This occasionally causes recvmsg() to
     stall indefinitely.

 (3) Fix a number of packet-transmitting work functions to hold an active
     count on the local endpoint so that the UDP socket doesn't get
     destroyed whilst they're calling kernel_sendmsg() on it.

 (4) Fix a NULL pointer deref that stemmed from a call's connection pointer
     being cleared when the call was disconnected.

Changes:

 v2: Removed a couple of BUG() statements that got added.
====================

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 23 insertions, 19 deletions

diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c
index 48f67a9b1037..923b263c401b 100644
--- a/net/rxrpc/peer_event.c
+++ b/net/rxrpc/peer_event.c
@@ -364,27 +364,31 @@ static void rxrpc_peer_keepalive_dispatch(struct rxrpc_net *rxnet,
 		if (!rxrpc_get_peer_maybe(peer))
 			continue;
 
-		spin_unlock_bh(&rxnet->peer_hash_lock);
-
-		keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME;
-		slot = keepalive_at - base;
-		_debug("%02x peer %u t=%d {%pISp}",
-		       cursor, peer->debug_id, slot, &peer->srx.transport);
+		if (__rxrpc_use_local(peer->local)) {
+			spin_unlock_bh(&rxnet->peer_hash_lock);
+
+			keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME;
+			slot = keepalive_at - base;
+			_debug("%02x peer %u t=%d {%pISp}",
+			       cursor, peer->debug_id, slot, &peer->srx.transport);
+
+			if (keepalive_at <= base ||
+			    keepalive_at > base + RXRPC_KEEPALIVE_TIME) {
+				rxrpc_send_keepalive(peer);
+				slot = RXRPC_KEEPALIVE_TIME;
+			}
 
-		if (keepalive_at <= base ||
-		    keepalive_at > base + RXRPC_KEEPALIVE_TIME) {
-			rxrpc_send_keepalive(peer);
-			slot = RXRPC_KEEPALIVE_TIME;
+			/* A transmission to this peer occurred since last we
+			 * examined it so put it into the appropriate future
+			 * bucket.
+			 */
+			slot += cursor;
+			slot &= mask;
+			spin_lock_bh(&rxnet->peer_hash_lock);
+			list_add_tail(&peer->keepalive_link,
+				      &rxnet->peer_keepalive[slot & mask]);
+			rxrpc_unuse_local(peer->local);
 		}
-
-		/* A transmission to this peer occurred since last we examined
-		 * it so put it into the appropriate future bucket.
-		 */
-		slot += cursor;
-		slot &= mask;
-		spin_lock_bh(&rxnet->peer_hash_lock);
-		list_add_tail(&peer->keepalive_link,
-			      &rxnet->peer_keepalive[slot & mask]);
 		rxrpc_put_peer_locked(peer);
 	}