[PATCH] fbdev: hitfb: fix reference leak on failed device registration

Guangshuo Li posted 1 patch 2 months ago
drivers/video/fbdev/hitfb.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
[PATCH] fbdev: hitfb: fix reference leak on failed device registration
Posted by Guangshuo Li 2 months ago
When platform_device_register() fails in hitfb_init(), the embedded
struct device in hitfb_device has already been initialized by
device_initialize(), but the failure path only unregisters the platform
driver and does not drop the device reference for the current platform
device:

  hitfb_init()
    -> platform_device_register(&hitfb_device)
       -> device_initialize(&hitfb_device.dev)
       -> setup_pdev_dma_masks(&hitfb_device)
       -> platform_device_add(&hitfb_device)

This leads to a reference leak when platform_device_register() fails.
Fix this by calling platform_device_put() before unregistering the
platform driver.

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

Fixes: 048839dc548a5 ("video: hitfb suspend/resume and updates.")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/video/fbdev/hitfb.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/hitfb.c b/drivers/video/fbdev/hitfb.c
index 97db325df2b4..29708c2d506d 100644
--- a/drivers/video/fbdev/hitfb.c
+++ b/drivers/video/fbdev/hitfb.c
@@ -495,8 +495,10 @@ static int __init hitfb_init(void)
 	ret = platform_driver_register(&hitfb_driver);
 	if (!ret) {
 		ret = platform_device_register(&hitfb_device);
-		if (ret)
+		if (ret) {
+			platform_device_put(&hitfb_device);
 			platform_driver_unregister(&hitfb_driver);
+		}
 	}
 	return ret;
 }
-- 
2.43.0
Re: [PATCH] fbdev: hitfb: fix reference leak on failed device registration
Posted by Guangshuo Li 1 month, 3 weeks ago
Hi,

Please disregard this patch.

On Thu, 16 Apr 2026 at 03:10, Guangshuo Li <lgs201920130244@gmail.com> wrote:
>
> When platform_device_register() fails in hitfb_init(), the embedded
> struct device in hitfb_device has already been initialized by
> device_initialize(), but the failure path only unregisters the platform
> driver and does not drop the device reference for the current platform
> device:
>
>   hitfb_init()
>     -> platform_device_register(&hitfb_device)
>        -> device_initialize(&hitfb_device.dev)
>        -> setup_pdev_dma_masks(&hitfb_device)
>        -> platform_device_add(&hitfb_device)
>
> This leads to a reference leak when platform_device_register() fails.
> Fix this by calling platform_device_put() before unregistering the
> platform driver.
>
> The issue was identified by a static analysis tool I developed and
> confirmed by manual review.
>
> Fixes: 048839dc548a5 ("video: hitfb suspend/resume and updates.")
> Cc: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
> ---
>  drivers/video/fbdev/hitfb.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/video/fbdev/hitfb.c b/drivers/video/fbdev/hitfb.c
> index 97db325df2b4..29708c2d506d 100644
> --- a/drivers/video/fbdev/hitfb.c
> +++ b/drivers/video/fbdev/hitfb.c
> @@ -495,8 +495,10 @@ static int __init hitfb_init(void)
>         ret = platform_driver_register(&hitfb_driver);
>         if (!ret) {
>                 ret = platform_device_register(&hitfb_device);
> -               if (ret)
> +               if (ret) {
> +                       platform_device_put(&hitfb_device);
>                         platform_driver_unregister(&hitfb_driver);
> +               }
>         }
>         return ret;
>  }
> --
> 2.43.0
>

After re-checking it, hitfb_device is a static platform_device and it does
not provide a dev.release callback. Therefore calling
platform_device_put() on the platform_device_register() failure path is
not appropriate here and can trigger the missing release callback
warning.

This falls into the same static platform_device pattern pointed out in
the other reviews, so I will drop this patch.

Sorry for the noise.

Best regards,
Guangshuo Li