FAILED: patch "[PATCH] selftests: mptcp: join: check RM_ADDR not sent over same" failed to apply to 5.15-stable tree

PATCH [email protected] 2 participants 2 messages Mar 9

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author maintainer

2026-03-09 10:30 UTC #0 lore raw

The patch below does not apply to the 5.15-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 <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 560edd99b5f58b2d4bbe3c8e51e1eed68d887b0e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026030948-nickname-laxative-fd1d@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 560edd99b5f58b2d4bbe3c8e51e1eed68d887b0e Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <[email protected]>
Date: Tue, 3 Mar 2026 11:56:04 +0100
Subject: [PATCH] selftests: mptcp: join: check RM_ADDR not sent over same
subflow

This validates the previous commit: RM_ADDR were sent over the first found active subflow which could be the same as the one being removed. It is more likely to loose this notification.

For this check, RM_ADDR are explicitly dropped when trying to send them over the initial subflow, when removing the endpoint attached to it. If it is dropped, the test will complain because some RM_ADDR have not been received.

Note that only the RM_ADDR are dropped, to allow the linked subflow to be quickly and cleanly closed. To only drop those RM_ADDR, a cBPF byte code is used. If the IPTables commands fail, that's OK, the tests will continue to pass, but not validate this part. This can be ignored:
another subtest fully depends on such command, and will be marked as skipped.

The 'Fixes' tag here below is the same as the one from the previous
commit: this patch here is not fixing anything wrong in the selftests, but it validates the previous fix for an issue introduced by this commit ID.

Fixes 8dd5efb1f91b ("mptcp: send ack for rm_addr")

Cc [email protected]

Reviewed-by Mat Martineau <[email protected]>

Signed-off-by Matthieu Baerts (NGI0) <[email protected]>

Link https://patch.msgid.link/20260303-net-mptcp-misc-fixes-7-0-rc2-v1-3-4b5462b6f016@kernel.org open here

Signed-off-by Jakub Kicinski <[email protected]>

tools/testing/selftests/net/mptcp/mptcp_join.sh +36 -0

index dc1f200aaa81..058ad5a13d24 100755
@@ -104,6 +104,24 @@ CBPF_MPTCP_SUBOPTION_ADD_ADDR="14,
 			       6 0 0 65535,
 			       6 0 0 0"
 
+# IPv4: TCP hdr of 48B, a first suboption of 12B (DACK8), the RM_ADDR suboption
+# generated using "nfbpf_compile '(ip[32] & 0xf0) == 0xc0 && ip[53] == 0x0c &&
+#				  (ip[66] & 0xf0) == 0x40'"
+CBPF_MPTCP_SUBOPTION_RM_ADDR="13,
+			      48 0 0 0,
+			      84 0 0 240,
+			      21 0 9 64,
+			      48 0 0 32,
+			      84 0 0 240,
+			      21 0 6 192,
+			      48 0 0 53,
+			      21 0 4 12,
+			      48 0 0 66,
+			      84 0 0 240,
+			      21 0 1 64,
+			      6 0 0 65535,
+			      6 0 0 0"
+
 init_partial()
 {
 	capout=$(mktemp)

@@ -4217,6 +4235,14 @@ endpoint_tests()
 		chk_subflow_nr "after no reject" 3
 		chk_mptcp_info subflows 2 subflows 2
 
+		# To make sure RM_ADDR are sent over a different subflow, but
+		# allow the rest to quickly and cleanly close the subflow
+		local ipt=1
+		ip netns exec "${ns2}" ${iptables} -I OUTPUT -s "10.0.1.2" \
+			-p tcp -m tcp --tcp-option 30 \
+			-m bpf --bytecode \
+			"$CBPF_MPTCP_SUBOPTION_RM_ADDR" \
+			-j DROP || ipt=0
 		local i
 		for i in $(seq 3); do
 			pm_nl_del_endpoint $ns2 1 10.0.1.2

@@ -4229,6 +4255,7 @@ endpoint_tests()
 			chk_subflow_nr "after re-add id 0 ($i)" 3
 			chk_mptcp_info subflows 3 subflows 3
 		done
+		[ ${ipt} = 1 ] && ip netns exec "${ns2}" ${iptables} -D OUTPUT 1
 
 		mptcp_lib_kill_group_wait $tests_pid

@@ -4288,11 +4315,20 @@ endpoint_tests()
 		chk_mptcp_info subflows 2 subflows 2
 		chk_mptcp_info add_addr_signal 2 add_addr_accepted 2
 
+		# To make sure RM_ADDR are sent over a different subflow, but
+		# allow the rest to quickly and cleanly close the subflow
+		local ipt=1
+		ip netns exec "${ns1}" ${iptables} -I OUTPUT -s "10.0.1.1" \
+			-p tcp -m tcp --tcp-option 30 \
+			-m bpf --bytecode \
+			"$CBPF_MPTCP_SUBOPTION_RM_ADDR" \
+			-j DROP || ipt=0
 		pm_nl_del_endpoint $ns1 42 10.0.1.1
 		sleep 0.5
 		chk_subflow_nr "after delete ID 0" 2
 		chk_mptcp_info subflows 2 subflows 2
 		chk_mptcp_info add_addr_signal 2 add_addr_accepted 2
+		[ ${ipt} = 1 ] && ip netns exec "${ns1}" ${iptables} -D OUTPUT 1
 
 		pm_nl_add_endpoint $ns1 10.0.1.1 id 99 flags signal
 		wait_mpj 4

Matthieu Baerts

maintainer

2026-03-09 18:30 UTC #1 lore raw

Hi Greg, Sasha,

Quoted 5 lines · On 09/03/2026 11:29, [email protected] wrote:

The patch below does not apply to the 5.15-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 <[email protected]>.

Thank you for the notification! And thank you Sasha for having resolved some conflicts already!

(...)

Quoted 24 lines

------------------ original commit in Linus's tree ------------------
From 560edd99b5f58b2d4bbe3c8e51e1eed68d887b0e Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <[email protected]>
Date: Tue, 3 Mar 2026 11:56:04 +0100
Subject: [PATCH] selftests: mptcp: join: check RM_ADDR not sent over same
subflow
This validates the previous commit: RM_ADDR were sent over the first found active subflow which could be the same as the one being removed. It is more likely to loose this notification.
For this check, RM_ADDR are explicitly dropped when trying to send them over the initial subflow, when removing the endpoint attached to it. If it is dropped, the test will complain because some RM_ADDR have not been received.
Note that only the RM_ADDR are dropped, to allow the linked subflow to be quickly and cleanly closed. To only drop those RM_ADDR, a cBPF byte code is used. If the IPTables commands fail, that's OK, the tests will continue to pass, but not validate this part. This can be ignored:
another subtest fully depends on such command, and will be marked as skipped.

Quoted 4 lines

The 'Fixes' tag here below is the same as the one from the previous
commit: this patch here is not fixing anything wrong in the selftests, but it validates the previous fix for an issue introduced by this commit ID.

No need to backport this patch: it is just a validation in the selftest for the parent commit, and the subtest that it modifies is not in v5.15. CI can use newer selftests version to validate the fix on v5.15.

Cheers,
Matt

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