Paolo, Matthieu - I'm not currently planning to backport this but if you 
think it's worthwhile, let me know.

-Mat


---------- Forwarded message ----------
Date: Sun, 13 Feb 2022 23:24:18
From: gregkh
Subject: FAILED: patch "[PATCH] selftests: mptcp: add missing join check" failed
      to apply to 5.16-stable tree


The patch below does not apply to the 5.16-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 857898eb4b28daf3faca3ae334c78b2bb141475e Mon Sep 17 00:00:00 2001
From: Matthieu Baerts <matthieu.baerts@tessares.net>
Date: Wed, 9 Feb 2022 17:25:07 -0800
Subject: [PATCH] selftests: mptcp: add missing join check

This function also writes the name of the test with its ID, making clear
a new test has been executed.

Without that, the ADD_ADDR results from this test was appended at the
end of the previous test causing confusions. Especially when the second
test was failing, we had:

   17 signal invalid addresses     syn[ ok ] - synack[ ok ] - ack[ ok ]
                                   add[ ok ] - echo  [ ok ]
                                   add[fail] got 2 ADD_ADDR[s] expected 3

In fact, this 17th test was OK but not the 18th one.

Now we have:

   17 signal invalid addresses     syn[ ok ] - synack[ ok ] - ack[ ok ]
                                   add[ ok ] - echo  [ ok ]
   18 signal addresses race test   syn[fail] got 2 JOIN[s] syn expected 3
    - synack[fail] got 2 JOIN[s] synack expected
    - ack[fail] got 2 JOIN[s] ack expected 3
                                   add[fail] got 2 ADD_ADDR[s] expected 3

Fixes: 33c563ad28e3 ("selftests: mptcp: add_addr and echo race test")
Reported-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index b8bdbec0cf69..c0801df15f54 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -1159,6 +1159,7 @@ signal_address_tests()
  	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags signal
  	ip netns exec $ns2 ./pm_nl_ctl add 10.0.4.2 flags signal
  	run_tests $ns1 $ns2 10.0.1.1
+	chk_join_nr "signal addresses race test" 3 3 3

  	# the server will not signal the address terminating
  	# the MPC subflow