From 47dcc20a39d06585bf3cb9fb381f0e81c20002c3 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Fri, 6 May 2016 09:46:18 -0700
Subject: [PATCH] ipv4: tcp: ip_send_unicast_reply() is not BH safe
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 <edumazet@google.com>
Reported-by: Andres Lagar-Cavilla <andreslc@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
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 a7ab9472d645..8219d0d8dc83 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)
--
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