net: tcp: remove BUG_ON from tcp_v4_err

if skb is NULL pointer, and the following access of skb's
skb_mstamp_ns will trigger panic, which is same as BUG_ON

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index a336787..5424a40 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -542,7 +542,6 @@ int tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
                icsk->icsk_rto = inet_csk_rto_backoff(icsk, TCP_RTO_MAX);
 
                skb = tcp_rtx_queue_head(sk);
-               BUG_ON(!skb);
 
                tcp_mstamp_refresh(tp);
                delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));