[PATC net-next] tcp: must block bh in __inet_twsk_hashdance()

[Eric Dumazet]

From: Eric Dumazet <eduma...@google.com>

__inet_twsk_hashdance() might be called from process context,
better block BH before acquiring bind hash and established locks

Fixes: c10d9310edf5 ("tcp: do not assume TCP code is non preemptible")
Signed-off-by: Eric Dumazet <eduma...@google.com>
---
 net/ipv4/inet_timewait_sock.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index 
99ee5c4a9b6844929a995b0b4b5bd693bb211123..2065816748066986f0356df168c2d76fe2d53d85
 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -94,7 +94,7 @@ static void inet_twsk_add_bind_node(struct inet_timewait_sock 
*tw,
 }
 
 /*
- * Enter the time wait state. This is called with locally disabled BH.
+ * Enter the time wait state.
  * Essentially we whip up a timewait bucket, copy the relevant info into it
  * from the SK, and mess with hash chains and list linkage.
  */
@@ -112,7 +112,7 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, 
struct sock *sk,
         */
        bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), inet->inet_num,
                        hashinfo->bhash_size)];
-       spin_lock(&bhead->lock);
+       spin_lock_bh(&bhead->lock);
        tw->tw_tb = icsk->icsk_bind_hash;
        WARN_ON(!icsk->icsk_bind_hash);
        inet_twsk_add_bind_node(tw, &tw->tw_tb->owners);
@@ -138,7 +138,7 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, 
struct sock *sk,
        if (__sk_nulls_del_node_init_rcu(sk))
                sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
 
-       spin_unlock(lock);
+       spin_unlock_bh(lock);
 }
 EXPORT_SYMBOL_GPL(__inet_twsk_hashdance);