FAILED: patch "[PATCH] mptcp: pm: ADD_ADDR rtx: allow ID 0" failed to apply to 5.15-stable tree

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 03f324f3f1f7619a47b9c91282cb12775ab0a2f1
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026051201-garbage-juror-82cc@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 03f324f3f1f7619a47b9c91282cb12775ab0a2f1 Mon Sep 17 00:00:00 2001
From: "Matthieu Baerts (NGI0)" <[email protected]>
Date: Tue, 5 May 2026 17:00:50 +0200
Subject: [PATCH] mptcp: pm: ADD_ADDR rtx: allow ID 0

ADD_ADDR can be sent for the ID 0, which corresponds to the local address and port linked to the initial subflow.

Indeed, this address could be removed, and re-added later on, e.g. what is done in the "delete re-add signal" MPTCP Join selftests. So no reason to ignore it.

index 57a456690406..5056eb8db24e 100644
@@ -337,9 +337,6 @@ static void mptcp_pm_add_timer(struct timer_list *timer)
 	if (inet_sk_state_load(sk) == TCP_CLOSE)
 		return;
 
-	if (!entry->addr.id)
-		return;
-
 	if (mptcp_pm_should_add_signal_addr(msk)) {
 		sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX / 8);
 		goto out;

From: "Matthieu Baerts (NGI0)" <[email protected]>

[ Upstream commit 03f324f3f1f7619a47b9c91282cb12775ab0a2f1 ]

ADD_ADDR can be sent for the ID 0, which corresponds to the local address and port linked to the initial subflow.

Indeed, this address could be removed, and re-added later on, e.g. what is done in the "delete re-add signal" MPTCP Join selftests. So no reason to ignore it.

---
 net/mptcp/pm_netlink.c | 3 ---
 1 file changed, 3 deletions(-)

index 6fb14148a96e0..53edf23a85c5f 100644
@@ -327,9 +327,6 @@ static void mptcp_pm_add_timer(struct timer_list *timer)
 	if (inet_sk_state_load(sk) == TCP_CLOSE)
 		return;
 
-	if (!entry->addr.id)
-		return;
-
 	if (mptcp_pm_should_add_signal_addr(msk)) {
 		sk_reset_timer(sk, timer, jiffies + TCP_RTO_MAX / 8);
 		goto out;

2.53.0