FAILED: patch "[PATCH] batman-adv: retrieve ethhdr after potential skb realloc on RX" failed to apply to 6.12-stable tree

The patch below does not apply to the 6.12-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-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 035e1fed892d3d06002a73ff73668f618a514644
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026072056-gothic-untreated-85a2@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

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

From 035e1fed892d3d06002a73ff73668f618a514644 Mon Sep 17 00:00:00 2001
From: Sven Eckelmann <[email protected]>
Date: Sun, 28 Jun 2026 06:44:13 +0200
Subject: [PATCH] batman-adv: retrieve ethhdr after potential skb realloc on RX

pskb_may_pull() in batadv_interface_rx() could reallocate the buffer behind the skb. Variables which were pointing to the old buffer need to be reassigned to avoid an use-after-free.

This was done correctly for the VLAN header but missed for the ethernet header which is later used for the TT and AP isolation handling.

index 44026810b99c..511f70e0706a 100644
@@ -434,6 +434,7 @@ void batadv_interface_rx(struct net_device *mesh_iface,
 		if (!pskb_may_pull(skb, VLAN_ETH_HLEN))
 			goto dropped;
 
+		ethhdr = eth_hdr(skb);
 		vhdr = skb_vlan_eth_hdr(skb);
 
 		/* drop batman-in-batman packets to prevent loops */

commit 035e1fed892d3d06002a73ff73668f618a514644 upstream.

pskb_may_pull() in batadv_interface_rx() could reallocate the buffer behind the skb. Variables which were pointing to the old buffer need to be reassigned to avoid an use-after-free.

This was done correctly for the VLAN header but missed for the ethernet header which is later used for the TT and AP isolation handling.

---
 net/batman-adv/soft-interface.c | 1 +
 1 file changed, 1 insertion(+)

index f46064333f334..42ad04d356904 100644
@@ -445,6 +445,7 @@ void batadv_interface_rx(struct net_device *soft_iface,
 		if (!pskb_may_pull(skb, VLAN_ETH_HLEN))
 			goto dropped;
 
+		ethhdr = eth_hdr(skb);
 		vhdr = skb_vlan_eth_hdr(skb);
 
 		/* drop batman-in-batman packets to prevent loops */

2.47.3

Queued for 6.12, thanks.

Thanks,
Sasha