Commit acb4a6bf authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

tcp: ensure prior synack rtx behavior with small backlogs

Some applications use a listen() backlog of 1.

Prior kernels were silently enforcing a qlen_log of 4, so that we were
sending up to /proc/sys/net/ipv4/tcp_synack_retries SYNACK messages.

Fixes: ef547f2a ("tcp: remove max_qlen_log")
Signed-off-by: default avatarEric Dumazet <>
Signed-off-by: default avatarDavid S. Miller <>
parent 686a5624
......@@ -579,7 +579,7 @@ static void reqsk_timer_handler(unsigned long data)
* ones are about to clog our table.
qlen = reqsk_queue_len(queue);
if ((qlen << 1) > sk_listener->sk_max_ack_backlog) {
if ((qlen << 1) > max(8U, sk_listener->sk_max_ack_backlog)) {
int young = reqsk_queue_len_young(queue) << 1;
while (thresh > 2) {
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