FAILED: patch "[PATCH] net/mlx5: HWS, fix matcher leak on resize target setup" failed to apply to 6.12-stable tree

[<gregkh@linuxfoundation.org>]

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 <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-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x bb09d0e64ecaa0aa0f7d1133a1696ed74dead295
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026072123-treason-bush-df20@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

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

From bb09d0e64ecaa0aa0f7d1133a1696ed74dead295 Mon Sep 17 00:00:00 2001
From: Dawei Feng <dawei.feng@seu.edu.cn>
Date: Mon, 29 Jun 2026 14:40:49 +0800
Subject: [PATCH] net/mlx5: HWS, fix matcher leak on resize target setup
 failure

hws_bwc_matcher_move() allocates a replacement matcher before setting it
as the resize target. If mlx5hws_matcher_resize_set_target() fails, the
replacement matcher is not attached anywhere and is leaked.

Fix the leak by destroying the replacement matcher before returning from
the resize-target failure path.

The bug was first flagged by an experimental analysis tool we are
developing for kernel memory-management bugs while analyzing
v6.13-rc1. The tool is still under development and is not yet publicly
available. Manual inspection confirms that the bug is still
present in v7.1.1.

An x86_64 allyesconfig build showed no new warnings. As we do not have a
mlx5 HWS-capable device to test with, no runtime testing was able to be
performed.

Fixes: 2111bb970c78 ("net/mlx5: HWS, added backward-compatible API handling")
Cc: stable@vger.kernel.org
Signed-off-by: Dawei Feng <dawei.feng@seu.edu.cn>
Reviewed-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Acked-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20260629064049.3852759-1-dawei.feng@seu.edu.cn
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc.c
index eae02bc74221..3bcf412a08c4 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/hws/bwc.c
@@ -205,6 +205,7 @@ static int hws_bwc_matcher_move(struct mlx5hws_bwc_matcher *bwc_matcher)
 	ret = mlx5hws_matcher_resize_set_target(old_matcher, new_matcher);
 	if (ret) {
 		mlx5hws_err(ctx, "Rehash error: failed setting resize target\n");
+		mlx5hws_matcher_destroy(new_matcher);
 		return ret;
 	}