From 3a493b762f31fc0c571051cdfb0d80f49498e5fd Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 15 Feb 2019 13:36:20 -0800 Subject: tcp: clear icsk_backoff in tcp_write_queue_purge() [ Upstream commit 04c03114be82194d4a4858d41dba8e286ad1787c ] soukjin bae reported a crash in tcp_v4_err() handling ICMP_DEST_UNREACH after tcp_write_queue_head(sk) returned a NULL pointer. Current logic should have prevented this : if (seq != tp->snd_una || !icsk->icsk_retransmits || !icsk->icsk_backoff || fastopen) break; Problem is the write queue might have been purged and icsk_backoff has not been cleared. Signed-off-by: Eric Dumazet Reported-by: soukjin bae Acked-by: Neal Cardwell Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp.c | 1 - 1 file changed, 1 deletion(-) (limited to 'net/ipv4') diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index fd14501ac3af..00ae9a1d44ed 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2347,7 +2347,6 @@ int tcp_disconnect(struct sock *sk, int flags) tp->write_seq += tp->max_window + 2; if (tp->write_seq == 0) tp->write_seq = 1; - icsk->icsk_backoff = 0; tp->snd_cwnd = 2; icsk->icsk_probes_out = 0; tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; -- cgit v1.2.3