[PATCH] soc: microchip: mpfs-sys-controller: fix reference leak on failed device registration

[Guangshuo Li]

When platform_device_register() fails in mpfs_sys_controller_probe(),
the embedded struct device in subdevs[i] has already been initialized by
device_initialize(), but the failure path only reports the error and
does not drop the device reference for the current platform device:

  mpfs_sys_controller_probe()
    -> platform_device_register(&subdevs[i])
       -> device_initialize(&subdevs[i].dev)
       -> setup_pdev_dma_masks(&subdevs[i])
       -> platform_device_add(&subdevs[i])

This leads to a reference leak when platform_device_register() fails.
Fix this by calling platform_device_put() after reporting the error.

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

Fixes: d0054a470c339 ("soc: add microchip polarfire soc system controller")
Cc: stable at vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244 at gmail.com>
---
 drivers/soc/microchip/mpfs-sys-controller.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/microchip/mpfs-sys-controller.c b/drivers/soc/microchip/mpfs-sys-controller.c
index 10b2fc39da66..404c31daf459 100644
--- a/drivers/soc/microchip/mpfs-sys-controller.c
+++ b/drivers/soc/microchip/mpfs-sys-controller.c
@@ -168,8 +168,10 @@ static int mpfs_sys_controller_probe(struct platform_device *pdev)
 
 	for (i = 0; i < ARRAY_SIZE(subdevs); i++) {
 		subdevs[i].dev.parent = dev;
-		if (platform_device_register(&subdevs[i]))
+		if (platform_device_register(&subdevs[i])) {
 			dev_warn(dev, "Error registering sub device %s\n", subdevs[i].name);
+			platform_device_put(&subdevs[i]);
+		}
 	}
 
 	dev_info(&pdev->dev, "Registered MPFS system controller\n");
-- 
2.43.0