| From | alexander.levin@verizon ... | Subject | [PATCH AUTOSEL for 4.9 41/54] tcp: correct memory barrier usage in tcp_check_space() | Date | Wed, 22 Nov 2017 22:24:01 +0000 |
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From: Jason Baron <jbaron@akamai.com>
[ Upstream commit 56d806222ace4c3aeae516cd7a855340fb2839d8 ]
sock_reset_flag() maps to __clear_bit() not the atomic version clear_bit(). Thus, we need smp_mb(), smp_mb__after_atomic() is not sufficient.
Fixes: 3c7151275c0c ("tcp: add memory barriers to write space paths") Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Jason Baron <jbaron@akamai.com> Acked-by: Eric Dumazet <edumazet@google.com> Reported-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> --- net/ipv4/tcp_input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 8fcd0c642742..05255a286888 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5081,7 +5081,7 @@ static void tcp_check_space(struct sock *sk) if (sock_flag(sk, SOCK_QUEUE_SHRUNK)) { sock_reset_flag(sk, SOCK_QUEUE_SHRUNK); /* pairs with tcp_poll() */ - smp_mb__after_atomic(); + smp_mb(); if (sk->sk_socket && test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) tcp_new_space(sk); -- 2.11.0
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