[PATCH] platform/chrome: fix reference leak on failed device registration

[Guangshuo Li]

When platform_device_register() fails in chromeos_pstore_init(), the
embedded struct device in chromeos_ramoops has already been initialized
by device_initialize(), but the failure path returns the error without
dropping the device reference for the current platform device:

  chromeos_pstore_init()
    -> platform_device_register(&chromeos_ramoops)
       -> device_initialize(&chromeos_ramoops.dev)
       -> setup_pdev_dma_masks(&chromeos_ramoops)
       -> platform_device_add(&chromeos_ramoops)

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

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

Fixes: 9742e127cd0dd ("platform/chrome: Add pstore platform_device")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Guangshuo Li <lgs201920130244@xxxxxxxxx>
---
 drivers/platform/chrome/chromeos_pstore.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/chrome/chromeos_pstore.c b/drivers/platform/chrome/chromeos_pstore.c
index a6eed99507d4..9e6d14dbb1c2 100644
--- a/drivers/platform/chrome/chromeos_pstore.c
+++ b/drivers/platform/chrome/chromeos_pstore.c
@@ -127,8 +127,13 @@ static int __init chromeos_pstore_init(void)
 	/* First check ACPI for non-hardcoded values from firmware. */
 	acpi_dev_found = chromeos_check_acpi();
 
-	if (acpi_dev_found || dmi_check_system(chromeos_pstore_dmi_table))
-		return platform_device_register(&chromeos_ramoops);
+	if (acpi_dev_found || dmi_check_system(chromeos_pstore_dmi_table)) {
+		ret = platform_device_register(&chromeos_ramoops);
+		if (ret)
+			platform_device_put(&chromeos_ramoops);
+
+		return ret;
+	}
 
 	return -ENODEV;
 }
-- 
2.43.0