From dadbc042500b57cb2ceb25bc0ec39583142e0c45 Mon Sep 17 00:00:00 2001 From: Randall Stewart Date: Mon, 6 Dec 2021 09:56:09 -0500 Subject: [PATCH] tcp: rack fails to send out a TLP after a MTU change When rack sends out a TLP it sets up various state to make sure it avoids the cwnd (its been more than 1 RTT since our last send) and it may at times send new data. If an MTU change as occurred and our cwnd has collapsed we can have a situation where must_retran flag is set and we obey the cwnd thus never sending the TLP and then sitting stuck. This one line fix addresses that problem Reviewed by: Michael Tuexen Sponsored by: Netflix Inc. Differential Revision: https://reviews.freebsd.org/D33231 --- sys/netinet/tcp_stacks/rack.c | 1 + 1 file changed, 1 insertion(+) diff --git a/sys/netinet/tcp_stacks/rack.c b/sys/netinet/tcp_stacks/rack.c index 7391734a9786..16faa887530f 100644 --- a/sys/netinet/tcp_stacks/rack.c +++ b/sys/netinet/tcp_stacks/rack.c @@ -17139,6 +17139,7 @@ rack_output(struct tcpcb *tp) len = cwin; } if (rack->r_must_retran && + (doing_tlp == 0) && (rsm == NULL)) { /* * Non-Sack and we had a RTO or Sack/non-Sack and a