Re: [PATCH] vme: Fix error not catched in fake_init()

[Greg KH]

On Mon, Dec 05, 2022 at 04:48:05PM +0800, Chen Zhongjin wrote:
> In fake_init(), __root_device_register() is possible to fail but it's
> ignored, which can cause unregistering vme_root fail when exit.
> 
>  general protection fault,
>  probably for non-canonical address 0xdffffc000000008c
>  KASAN: null-ptr-deref in range [0x0000000000000460-0x0000000000000467]
>  RIP: 0010:root_device_unregister+0x26/0x60
>  Call Trace:
>   <TASK>
>   __x64_sys_delete_module+0x34f/0x540
>   do_syscall_64+0x38/0x90
>   entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 
> Return error when __root_device_register() fails.
> 
> Fixes: 658bcdae9c67 ("vme: Adding Fake VME driver")
> Signed-off-by: Chen Zhongjin <chenzhongjin@xxxxxxxxxx>
> ---
>  drivers/staging/vme_user/vme_fake.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/staging/vme_user/vme_fake.c b/drivers/staging/vme_user/vme_fake.c
> index dd646b0c531d..1ee432c223e2 100644
> --- a/drivers/staging/vme_user/vme_fake.c
> +++ b/drivers/staging/vme_user/vme_fake.c
> @@ -1073,6 +1073,8 @@ static int __init fake_init(void)
>  
>  	/* We need a fake parent device */
>  	vme_root = __root_device_register("vme", THIS_MODULE);

This should be calling root_device_register() as well, not this version
of the call.

thanks,

greg k-h