FAILED: patch "[PATCH] platform/x86: simatic-ipc: fix platform device leak on registration failure" failed to apply to 6.1-stable tree

[Sasha Levin <sashal@kernel.org>]

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 <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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 9523698252fd583d6987582b9c34ec6500d10986
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '20261107054744-failed-6.1-9523698252fd@kernel.org' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'

Thanks,
Sasha

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

From 9523698252fd583d6987582b9c34ec6500d10986 Mon Sep 17 00:00:00 2001
From: Guangshuo Li <lgs201920130244@gmail.com>
Date: Thu, 24 Sep 2026 19:56:17 +0800
Subject: [PATCH] platform/x86: simatic-ipc: fix platform device leak on
 registration failure
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

register_platform_devices() registers the battery, LED, and watchdog
platform devices in sequence. If LED registration fails, the battery
device remains registered. If watchdog registration fails, the LED and
battery devices remain registered.

These failure paths leave successful platform_device_register_data()
calls without the matching platform_device_unregister() calls.

Add an unwind ladder to unregister previously registered platform
devices in reverse order before returning the registration error.

The issue was identified by a static analysis tool I developed and
confirmed by manual review.

Fixes: dd123e62bded ("platform/x86: simatic-ipc: add main driver for Siemens devices")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Link: https://patch.msgid.link/20260924115617.1578309-1-lgs201920130244@gmail.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 drivers/platform/x86/siemens/simatic-ipc.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/x86/siemens/simatic-ipc.c b/drivers/platform/x86/siemens/simatic-ipc.c
index 7039874d8f112..4a4509fc9263e 100644
--- a/drivers/platform/x86/siemens/simatic-ipc.c
+++ b/drivers/platform/x86/siemens/simatic-ipc.c
@@ -92,6 +92,7 @@ static int register_platform_devices(u32 station_id)
 	u8 wdtmode = SIMATIC_IPC_DEVICE_NONE;
 	u8 battmode = SIMATIC_IPC_DEVICE_NONE;
 	char *pdevname;
+	int ret;
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(device_modes); i++) {
@@ -139,8 +140,10 @@ static int register_platform_devices(u32 station_id)
 				pdevname, PLATFORM_DEVID_NONE,
 				&platform_data,
 				sizeof(struct simatic_ipc_platform));
-		if (IS_ERR(ipc_led_platform_device))
-			return PTR_ERR(ipc_led_platform_device);
+		if (IS_ERR(ipc_led_platform_device)) {
+			ret = PTR_ERR(ipc_led_platform_device);
+			goto err_unregister_batt;
+		}
 
 		pr_debug("device=%s created\n",
 			 ipc_led_platform_device->name);
@@ -153,8 +156,10 @@ static int register_platform_devices(u32 station_id)
 				KBUILD_MODNAME "_wdt", PLATFORM_DEVID_NONE,
 				&platform_data,
 				sizeof(struct simatic_ipc_platform));
-		if (IS_ERR(ipc_wdt_platform_device))
-			return PTR_ERR(ipc_wdt_platform_device);
+		if (IS_ERR(ipc_wdt_platform_device)) {
+			ret = PTR_ERR(ipc_wdt_platform_device);
+			goto err_unregister_led;
+		}
 
 		pr_debug("device=%s created\n",
 			 ipc_wdt_platform_device->name);
@@ -169,6 +174,14 @@ static int register_platform_devices(u32 station_id)
 	}
 
 	return 0;
+
+err_unregister_led:
+	if (ledmode != SIMATIC_IPC_DEVICE_NONE)
+		platform_device_unregister(ipc_led_platform_device);
+err_unregister_batt:
+	if (battmode != SIMATIC_IPC_DEVICE_NONE)
+		platform_device_unregister(ipc_batt_platform_device);
+	return ret;
 }
 
 static void request_additional_modules(u32 station_id)
-- 
2.53.0