[PATCH] char: xilinx_hwicap: unregister class on init errors

[PATCH] char: xilinx_hwicap: unregister class on init errors

[Myeonghun Pak]

hwicap_module_init() registers icap_class before reserving the
character-device region and registering the platform driver.  If either
of those later steps fails, the init path must undo the successful class
registration before returning an error.

Route the chrdev registration failure through a class unwind label, and
let the platform-driver registration failure fall through the existing
chrdev unwind before unregistering the class.  The normal module exit path
is unchanged.

This issue was identified during our ongoing static-analysis research while
reviewing kernel code.

Fixes: ef141a0bb0dc ("[POWERPC] Xilinx: hwicap driver")
Co-developed-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Myeonghun Pak <mhun512@gmail.com>

---
 drivers/char/xilinx_hwicap/xilinx_hwicap.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/char/xilinx_hwicap/xilinx_hwicap.c b/drivers/char/xilinx_hwicap/xilinx_hwicap.c
index 34a345dc5e..9bb5fa642f 100644
--- a/drivers/char/xilinx_hwicap/xilinx_hwicap.c
+++ b/drivers/char/xilinx_hwicap/xilinx_hwicap.c
@@ -760,7 +760,7 @@ static int __init hwicap_module_init(void)
 					HWICAP_DEVICES,
 					DRIVER_NAME);
 	if (retval < 0)
-		return retval;
+		goto failed_class;
 
 	retval = platform_driver_register(&hwicap_platform_driver);
 	if (retval)
@@ -771,6 +771,9 @@ static int __init hwicap_module_init(void)
  failed:
 	unregister_chrdev_region(devt, HWICAP_DEVICES);
 
+ failed_class:
+	class_unregister(&icap_class);
+
 	return retval;
 }
 
-- 
2.47.1

Re: [PATCH] char: xilinx_hwicap: unregister class on init errors

[Pandey, Radhey Shyam]

> hwicap_module_init() registers icap_class before reserving the
> character-device region and registering the platform driver.  If either
> of those later steps fails, the init path must undo the successful class
> registration before returning an error.
> 
> Route the chrdev registration failure through a class unwind label, and
> let the platform-driver registration failure fall through the existing
> chrdev unwind before unregistering the class.  The normal module exit path
> is unchanged.
> 
> This issue was identified during our ongoing static-analysis research while
> reviewing kernel code.
> 
> Fixes: ef141a0bb0dc ("[POWERPC] Xilinx: hwicap driver")
> Co-developed-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Ijae Kim <ae878000@gmail.com>
> Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
> 
> ---

Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Thanks!

>   drivers/char/xilinx_hwicap/xilinx_hwicap.c | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/char/xilinx_hwicap/xilinx_hwicap.c b/drivers/char/xilinx_hwicap/xilinx_hwicap.c
> index 34a345dc5e..9bb5fa642f 100644
> --- a/drivers/char/xilinx_hwicap/xilinx_hwicap.c
> +++ b/drivers/char/xilinx_hwicap/xilinx_hwicap.c
> @@ -760,7 +760,7 @@ static int __init hwicap_module_init(void)
>   					HWICAP_DEVICES,
>   					DRIVER_NAME);
>   	if (retval < 0)
> -		return retval;
> +		goto failed_class;
>   
>   	retval = platform_driver_register(&hwicap_platform_driver);
>   	if (retval)
> @@ -771,6 +771,9 @@ static int __init hwicap_module_init(void)
>    failed:
>   	unregister_chrdev_region(devt, HWICAP_DEVICES);
>   
> + failed_class:
> +	class_unregister(&icap_class);
> +
>   	return retval;
>   }
>