4.9.65-rt57-rc2 stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> Lockdep may complain about an unsafe locking scenario: | CPU0 CPU1 | ---- ---- | lock((tcp_sk_lock).lock); | lock(&per_cpu(local_softirq_locks[i], __cpu).lock); | lock((tcp_sk_lock).lock); | lock(&per_cpu(local_softirq_locks[i], __cpu).lock); in the call paths: do_current_softirqs -> tcp_v4_send_ack() vs tcp_v4_send_reset -> do_current_softirqs(). This should not happen since local_softirq_locks is per CPU. Reversing the order makes lockdep happy. Reported-by: Jacek Konieczny <jajcus@xxxxxxxxxx> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> --- 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 3336e1534bc5..3b7298459c87 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -698,8 +698,8 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) arg.tos = ip_hdr(skb)->tos; - local_lock(tcp_sk_lock); local_bh_disable(); + local_lock(tcp_sk_lock); 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, @@ -707,8 +707,8 @@ 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); - local_bh_enable(); local_unlock(tcp_sk_lock); + local_bh_enable(); #ifdef CONFIG_TCP_MD5SIG out: @@ -784,16 +784,16 @@ static void tcp_v4_send_ack(struct net *net, if (oif) arg.bound_dev_if = oif; arg.tos = tos; - local_lock(tcp_sk_lock); local_bh_disable(); + local_lock(tcp_sk_lock); 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); - local_bh_enable(); local_unlock(tcp_sk_lock); + local_bh_enable(); } static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) -- 2.13.2 -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
