[PATCH 6.1.y 4/4] platform/x86: simatic-ipc: fix platform device leak on registration failure

[Sasha Levin <sashal@kernel.org>]

From: Guangshuo Li <lgs201920130244@gmail.com>

[ Upstream commit 9523698252fd583d6987582b9c34ec6500d10986 ]

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>
[ sashal: omitted battery-device cleanup because the driver lacks battery-monitoring support ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/platform/x86/simatic-ipc.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/simatic-ipc.c b/drivers/platform/x86/simatic-ipc.c
index c773995b230d4..32c2a733ec49c 100644
--- a/drivers/platform/x86/simatic-ipc.c
+++ b/drivers/platform/x86/simatic-ipc.c
@@ -55,6 +55,7 @@ static int register_platform_devices(u32 station_id)
 	u8 ledmode = SIMATIC_IPC_DEVICE_NONE;
 	u8 wdtmode = SIMATIC_IPC_DEVICE_NONE;
 	char *pdevname = KBUILD_MODNAME "_leds";
+	int ret;
 	int i;
 
 	platform_data.devmode = SIMATIC_IPC_DEVICE_NONE;
@@ -97,8 +98,10 @@ 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);
@@ -112,6 +115,11 @@ 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);
+	return ret;
 }
 
 static int __init simatic_ipc_init_module(void)
-- 
2.53.0