FAILED: patch "[PATCH] Bluetooth: L2CAP: Fix null-ptr-deref in" failed to apply to 6.1-stable tree

The patch below does not apply to the 6.1-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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 78a88d43dab8d23aeef934ed8ce34d40e6b3d613
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026051216-resource-trading-20ac@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 78a88d43dab8d23aeef934ed8ce34d40e6b3d613 Mon Sep 17 00:00:00 2001
From: Siwei Zhang <[email protected]>
Date: Wed, 15 Apr 2026 16:53:36 -0400
Subject: [PATCH] Bluetooth: L2CAP: Fix null-ptr-deref in
l2cap_sock_get_sndtimeo_cb()

Add the same NULL guard already present in
l2cap_sock_resume_cb() and l2cap_sock_ready_cb().

index fb3cb70a5a39..879c9f90269a 100644
@@ -1761,6 +1761,9 @@ static long l2cap_sock_get_sndtimeo_cb(struct l2cap_chan *chan)
 {
 	struct sock *sk = chan->data;
 
+	if (!sk)
+		return 0;
+
 	return READ_ONCE(sk->sk_sndtimeo);
 }
 

Add the same NULL guard already present in
l2cap_sock_resume_cb() and l2cap_sock_ready_cb().

---
 net/bluetooth/l2cap_sock.c | 3 +++
 1 file changed, 3 insertions(+)

index 1960d35b3be0..adee617517bb 100644
@@ -1725,6 +1725,9 @@ static long l2cap_sock_get_sndtimeo_cb(struct l2cap_chan *chan)
 {
 	struct sock *sk = chan->data;
 
+	if (!sk)
+		return 0;
+
 	return sk->sk_sndtimeo;
 }
 

2.54.0

commit 78a88d43dab8d23aeef934ed8ce34d40e6b3d613 upstream.

Adjusted as stable does not have READ_ONCE around
sk->sk_sndtimeo.

Add the same NULL guard already present in
l2cap_sock_resume_cb() and l2cap_sock_ready_cb().

---
 net/bluetooth/l2cap_sock.c | 3 +++
 1 file changed, 3 insertions(+)

index 1960d35b3be0..adee617517bb 100644
@@ -1725,6 +1725,9 @@ static long l2cap_sock_get_sndtimeo_cb(struct l2cap_chan *chan)
 {
 	struct sock *sk = chan->data;
 
+	if (!sk)
+		return 0;
+
 	return sk->sk_sndtimeo;
 }
 

2.54.0