FAILED: patch "[PATCH] net: mana: fix use-after-free in add_adev() error path" failed to apply to 6.18-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 6.18-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-6.18.y
git checkout FETCH_HEAD
git cherry-pick -x c4ea7d8907cf72b259bf70bd8c2e791e1c4ff70f
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026033041-settle-wackiness-fce1@gregkh' --subject-prefix 'PATCH 6.18.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

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

From c4ea7d8907cf72b259bf70bd8c2e791e1c4ff70f Mon Sep 17 00:00:00 2001
From: Guangshuo Li <lgs201920130244@gmail.com>
Date: Tue, 24 Mar 2026 00:57:30 +0800
Subject: [PATCH] net: mana: fix use-after-free in add_adev() error path

If auxiliary_device_add() fails, add_adev() jumps to add_fail and calls
auxiliary_device_uninit(adev).

The auxiliary device has its release callback set to adev_release(),
which frees the containing struct mana_adev. Since adev is embedded in
struct mana_adev, the subsequent fall-through to init_fail and access
to adev->id may result in a use-after-free.

Fix this by saving the allocated auxiliary device id in a local
variable before calling auxiliary_device_add(), and use that saved id
in the cleanup path after auxiliary_device_uninit().

Fixes: a69839d4327d ("net: mana: Add support for auxiliary device")
Cc: stable@vger.kernel.org
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Link: https://patch.msgid.link/20260323165730.945365-1-lgs201920130244@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index 9017e806ecda..dca62fb9a3a9 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -3425,6 +3425,7 @@ static int add_adev(struct gdma_dev *gd, const char *name)
 	struct auxiliary_device *adev;
 	struct mana_adev *madev;
 	int ret;
+	int id;
 
 	madev = kzalloc_obj(*madev);
 	if (!madev)
@@ -3434,7 +3435,8 @@ static int add_adev(struct gdma_dev *gd, const char *name)
 	ret = mana_adev_idx_alloc();
 	if (ret < 0)
 		goto idx_fail;
-	adev->id = ret;
+	id = ret;
+	adev->id = id;
 
 	adev->name = name;
 	adev->dev.parent = gd->gdma_context->dev;
@@ -3460,7 +3462,7 @@ static int add_adev(struct gdma_dev *gd, const char *name)
 	auxiliary_device_uninit(adev);
 
 init_fail:
-	mana_adev_idx_free(adev->id);
+	mana_adev_idx_free(id);
 
 idx_fail:
 	kfree(madev);