From a466589807a13da2b7fbb2776e01634b38a4233b 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 --- include/net/tcp.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/net') diff --git a/include/net/tcp.h b/include/net/tcp.h index a99f75ef6a73..14ec97309581 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1457,6 +1457,7 @@ static inline void tcp_write_queue_purge(struct sock *sk) sk_wmem_free_skb(sk, skb); sk_mem_reclaim(sk); tcp_clear_all_retrans_hints(tcp_sk(sk)); + inet_csk(sk)->icsk_backoff = 0; } static inline struct sk_buff *tcp_write_queue_head(const struct sock *sk) -- cgit v1.2.3