FAILED: patch "[PATCH] netfilter: ebtables: zero chainstack array" failed to apply to 5.15-stable tree

[<gregkh@linuxfoundation.org>]

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 <stable@vger.kernel.org>.

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 cbfe53599eebffd188938ab6774cc41794f6f9d5
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026071335-donator-saucy-140c@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

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

From cbfe53599eebffd188938ab6774cc41794f6f9d5 Mon Sep 17 00:00:00 2001
From: Florian Westphal <fw@strlen.de>
Date: Sat, 4 Jul 2026 10:23:31 +0200
Subject: [PATCH] netfilter: ebtables: zero chainstack array

sashiko reports:
 looking at ebtables table
 translation, could a sparse cpu_possible_mask lead to an uninitialized pointer
 free?

 If cpu_possible_mask is sparse (for example, CPU 0 and CPU 2 are possible,
 but CPU 1 is not), the allocation loop skips CPU 1. If vmalloc_node() fails at
 CPU 2, the cleanup loop will blindly decrement and call vfree() on
 newinfo->chainstack[1].

Not a real-world bug, such allocation isn't expected to fail
in the first place.

Cc: stable@vger.kernel.org
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Florian Westphal <fw@strlen.de>

diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 5b74ff827493..48187598cdd0 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -921,8 +921,7 @@ static int translate_table(struct net *net, const char *name,
 		 * if an error occurs
 		 */
 		newinfo->chainstack =
-			vmalloc_array(nr_cpu_ids,
-				      sizeof(*(newinfo->chainstack)));
+			vcalloc(nr_cpu_ids, sizeof(*(newinfo->chainstack)));
 		if (!newinfo->chainstack)
 			return -ENOMEM;
 		for_each_possible_cpu(i) {