Commit ba3bb0e7 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

tcp: fix SO_RCVLOWAT possible hangs under high mem pressure

Whenever tcp_try_rmem_schedule() returns an error, we are under
trouble and should make sure to wakeup readers so that they
can drain socket queues and eventually make room.

Fixes: 03f45c88 ("tcp: avoid extra wakeups for SO_RCVLOWAT users")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0da7536f
...@@ -4582,6 +4582,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb) ...@@ -4582,6 +4582,7 @@ static void tcp_data_queue_ofo(struct sock *sk, struct sk_buff *skb)
if (unlikely(tcp_try_rmem_schedule(sk, skb, skb->truesize))) { if (unlikely(tcp_try_rmem_schedule(sk, skb, skb->truesize))) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFODROP); NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPOFODROP);
sk->sk_data_ready(sk);
tcp_drop(sk, skb); tcp_drop(sk, skb);
return; return;
} }
...@@ -4828,6 +4829,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb) ...@@ -4828,6 +4829,7 @@ static void tcp_data_queue(struct sock *sk, struct sk_buff *skb)
sk_forced_mem_schedule(sk, skb->truesize); sk_forced_mem_schedule(sk, skb->truesize);
else if (tcp_try_rmem_schedule(sk, skb, skb->truesize)) { else if (tcp_try_rmem_schedule(sk, skb, skb->truesize)) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP); NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRCVQDROP);
sk->sk_data_ready(sk);
goto drop; goto drop;
} }
......
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