mptcp: avoid bogus reset on fallback close

commit ff18f9e upstream. Since the blamed commit, the MPTCP protocol unconditionally sends TCP resets on all the subflows on disconnect(). That fits full-blown MPTCP sockets - to implement the fastclose mechanism - but causes unexpected corruption of the data stream, caught as sporadic self-tests failures. Fixes: d21f834 ("mptcp: use fastclose on more edge scenarios") Cc: [email protected] Tested-by: Matthieu Baerts <[email protected]> Closes: multipath-tcp/mptcp_net-next#419 Signed-off-by: Paolo Abeni <[email protected]> Reviewed-by: Matthieu Baerts <[email protected]> Signed-off-by: Matthieu Baerts <[email protected]> Link: https://lore.kernel.org/r/20230803-upstream-net-20230803-misc-fixes-6-5-v1-3-6671b1ab11cc@tessares.net Signed-off-by: Jakub Kicinski <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
gregkh · Aug 16, 2023 · 3c78824 · 3c78824
1 parent 4f733a0
commit 3c78824
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
@@ -2335,7 +2335,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 
 	lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);
 
-	if (flags & MPTCP_CF_FASTCLOSE) {
+	if ((flags & MPTCP_CF_FASTCLOSE) && !__mptcp_check_fallback(msk)) {
 		/* be sure to force the tcp_disconnect() path,
 		 * to generate the egress reset
 		 */