Re: [PATCH] selftest/vm: clarify error statement in gup_test

[Andrew Morton]

On Wed, 30 Mar 2022 21:52:57 +0000 Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx> wrote:

> Print two possible reasons /sys/kernel/debug/gup_test
> cannot be opened to help users of this test diagnose
> failures.
> 
> Signed-off-by: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # 5.15+
>
> ...
>
> --- a/tools/testing/selftests/vm/gup_test.c
> +++ b/tools/testing/selftests/vm/gup_test.c
> @@ -205,7 +205,9 @@ int main(int argc, char **argv)
>  
>  	gup_fd = open("/sys/kernel/debug/gup_test", O_RDWR);
>  	if (gup_fd == -1) {
> -		perror("open");
> +		perror("failed to open /sys/kernel/debug/gup_test");
> +		printf("check if CONFIG_GUP_TEST is enabled in kernel config\n");
> +		printf("check if debugfs is mounted at /sys/kernel/debug\n");
>  		exit(1);
>  	}

Thanks.  I don't think this is -stable material...