From: Eric Dumazet <eduma...@google.com> I forgot that ip_send_unicast_reply() is not BH safe (yet).
Disabling preemption before calling it was not a good move. Fixes: c10d9310edf5 ("tcp: do not assume TCP code is non preemptible") Signed-off-by: Eric Dumazet <eduma...@google.com> Reported-by: Andres Lagar-Cavilla <andre...@google.com> --- net/ipv4/tcp_ipv4.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index a7ab9472d64560d86ea24ac1b6e1a7800f89989d..8219d0d8dc8370d0d3e6fc4cd17b4925617968ab 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -692,7 +692,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) offsetof(struct inet_timewait_sock, tw_bound_dev_if)); arg.tos = ip_hdr(skb)->tos; - preempt_disable(); + local_bh_disable(); ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk), skb, &TCP_SKB_CB(skb)->header.h4.opt, ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, @@ -700,7 +700,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) __TCP_INC_STATS(net, TCP_MIB_OUTSEGS); __TCP_INC_STATS(net, TCP_MIB_OUTRSTS); - preempt_enable(); + local_bh_enable(); #ifdef CONFIG_TCP_MD5SIG out: @@ -776,14 +776,14 @@ static void tcp_v4_send_ack(struct net *net, if (oif) arg.bound_dev_if = oif; arg.tos = tos; - preempt_disable(); + local_bh_disable(); ip_send_unicast_reply(*this_cpu_ptr(net->ipv4.tcp_sk), skb, &TCP_SKB_CB(skb)->header.h4.opt, ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, &arg, arg.iov[0].iov_len); __TCP_INC_STATS(net, TCP_MIB_OUTSEGS); - preempt_enable(); + local_bh_enable(); } static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb)