From: Alok Tiwari In rxrpc_post_response(), the code should be comparing the challenge serial number from the cached response before deciding to switch to a newer response, but looks at the newer packet private data instead, rendering the comparison always false. Fix this by switching to look at the older packet. Fix further[1] to substitute the new packet in place of the old one if newer and also to release whichever we don't use. Fixes: 5800b1cf3fd8 ("rxrpc: Allow CHALLENGEs to the passed to the app for a RESPONSE") Signed-off-by: Alok Tiwari Signed-off-by: David Howells Reviewed-by: Jeffrey Altman cc: Marc Dionne cc: Eric Dumazet cc: "David S. Miller" cc: Jakub Kicinski cc: Paolo Abeni cc: Simon Horman cc: linux-afs@lists.infradead.org cc: netdev@vger.kernel.org cc: stable@kernel.org Link: https://sashiko.dev/#/patchset/20260319150150.4189381-1-dhowells%40redhat.com [1] --- include/trace/events/rxrpc.h | 1 + net/rxrpc/conn_event.c | 5 +++-- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h index 869f97c9bf73..5edad6a624ad 100644 --- a/include/trace/events/rxrpc.h +++ b/include/trace/events/rxrpc.h @@ -185,6 +185,7 @@ EM(rxrpc_skb_put_input, "PUT input ") \ EM(rxrpc_skb_put_jumbo_subpacket, "PUT jumbo-sub") \ EM(rxrpc_skb_put_oob, "PUT oob ") \ + EM(rxrpc_skb_put_old_response, "PUT old-resp ") \ EM(rxrpc_skb_put_purge, "PUT purge ") \ EM(rxrpc_skb_put_purge_oob, "PUT purge-oob") \ EM(rxrpc_skb_put_response, "PUT response ") \ diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c index 98ad9b51ca2c..c50cbfc5a313 100644 --- a/net/rxrpc/conn_event.c +++ b/net/rxrpc/conn_event.c @@ -557,11 +557,11 @@ void rxrpc_post_response(struct rxrpc_connection *conn, struct sk_buff *skb) spin_lock_irq(&local->lock); old = conn->tx_response; if (old) { - struct rxrpc_skb_priv *osp = rxrpc_skb(skb); + struct rxrpc_skb_priv *osp = rxrpc_skb(old); /* Always go with the response to the most recent challenge. */ if (after(sp->resp.challenge_serial, osp->resp.challenge_serial)) - conn->tx_response = old; + conn->tx_response = skb; else old = skb; } else { @@ -569,4 +569,5 @@ void rxrpc_post_response(struct rxrpc_connection *conn, struct sk_buff *skb) } spin_unlock_irq(&local->lock); rxrpc_poke_conn(conn, rxrpc_conn_get_poke_response); + rxrpc_free_skb(old, rxrpc_skb_put_old_response); }