| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.7 77/79] mptcp: fix bogus sendmsg() return code under pressure | Date | Mon, 10 Aug 2020 17:21:36 +0200 |
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From: Paolo Abeni <pabeni@redhat.com>
[ Upstream commit 8555c6bfd5fddb1cf363d3cd157d70a1bb27f718 ]
In case of memory pressure, mptcp_sendmsg() may call sk_stream_wait_memory() after succesfully xmitting some bytes. If the latter fails we currently return to the user-space the error code, ignoring the succeful xmit.
Address the issue always checking for the xmitted bytes before mptcp_sendmsg() completes.
Fixes: f296234c98a8 ("mptcp: Add handling of incoming MP_JOIN requests") Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/mptcp/protocol.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -802,7 +802,6 @@ fallback: mptcp_set_timeout(sk, ssk); if (copied) { - ret = copied; tcp_push(ssk, msg->msg_flags, mss_now, tcp_sk(ssk)->nonagle, size_goal); @@ -815,7 +814,7 @@ fallback: release_sock(ssk); out: release_sock(sk); - return ret; + return copied ? : ret; } static void mptcp_wait_data(struct sock *sk, long *timeo)
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