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* [PATCH net-next] mptcp: update rtx timeout only if required.
@ 2020-11-18 22:05 Paolo Abeni
  2020-11-19  0:42 ` [MPTCP] " Mat Martineau
  0 siblings, 1 reply; 4+ messages in thread
From: Paolo Abeni @ 2020-11-18 22:05 UTC (permalink / raw)
  To: netdev; +Cc: Jakub Kicinski, mptcp

We must start the retransmission timer only there are
pending data in the rtx queue.
Otherwise we can hit a WARN_ON in mptcp_reset_timer(),
as syzbot demonstrated.

Reported-and-tested-by: syzbot+42aa53dafb66a07e5a24@syzkaller.appspotmail.com
Fixes: d9ca1de8c0cd ("mptcp: move page frag allocation in mptcp_sendmsg()")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/mptcp/protocol.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 8df013daea88..aeda4357de9a 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1261,11 +1261,12 @@ static void mptcp_push_pending(struct sock *sk, unsigned int flags)
 		mptcp_push_release(sk, ssk, &info);
 
 out:
-	/* start the timer, if it's not pending */
-	if (!mptcp_timer_pending(sk))
-		mptcp_reset_timer(sk);
-	if (copied)
+	if (copied) {
+		/* start the timer, if it's not pending */
+		if (!mptcp_timer_pending(sk))
+			mptcp_reset_timer(sk);
 		__mptcp_check_send_data_fin(sk);
+	}
 }
 
 static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
-- 
2.26.2


^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2020-11-20  5:55 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2020-11-18 22:05 [PATCH net-next] mptcp: update rtx timeout only if required Paolo Abeni
2020-11-19  0:42 ` [MPTCP] " Mat Martineau
2020-11-19 14:19   ` Naresh Kamboju
2020-11-20  5:55     ` Jakub Kicinski

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