diff mbox series

[net-next] mptcp: update rtx timeout only if required.

Message ID 1a72039f112cae048c44d398ffa14e0a1432db3d.1605737083.git.pabeni@redhat.com (mailing list archive)
State Accepted
Delegated to: Netdev Maintainers
Headers show
Series [net-next] mptcp: update rtx timeout only if required. | expand

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netdev/stable success Stable not CCed

Commit Message

Paolo Abeni Nov. 18, 2020, 10:05 p.m. UTC
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(-)

Comments

Mat Martineau Nov. 19, 2020, 12:42 a.m. UTC | #1
On Wed, 18 Nov 2020, Paolo Abeni wrote:

> 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(-)
>

Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>

--
Mat Martineau
Intel
Naresh Kamboju Nov. 19, 2020, 2:19 p.m. UTC | #2
On Thu, 19 Nov 2020 at 06:13, Mat Martineau
<mathew.j.martineau@linux.intel.com> wrote:
>
>
> On Wed, 18 Nov 2020, Paolo Abeni wrote:
>
> > 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(-)
> >
>
> Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>

Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>

The reported kernel warning was fixed after applying this fix on top of
Linux next tag  20201119.

- Naresh
Jakub Kicinski Nov. 20, 2020, 5:55 a.m. UTC | #3
On Thu, 19 Nov 2020 19:49:16 +0530 Naresh Kamboju wrote:
> > > 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>
> >
> > Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>  
> 
> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
> Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>

Applied, thanks!
diff mbox series

Patch

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)