Re: [PATCH 4/4] ptdump: add check_wx_pages debugfs attribute

[Heiko Carstens]

On Tue, Jan 09, 2024 at 01:14:38PM +0100, Christophe Leroy wrote:
> Add a writable attribute in debugfs to trigger a
> W^X pages check at any time.
> 
> To trigger the test, just echo any numeric value into
> /sys/kernel/debug/check_wx_pages
> 
> The result is provided into dmesg.
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
> ---
>  mm/ptdump.c | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
..
> +static int check_wx_debugfs_set(void *data, u64 val)
> +{
> +	ptdump_check_wx();
> +
> +	return 0;
> +}
> +
> +DEFINE_SIMPLE_ATTRIBUTE(check_wx_fops, NULL, check_wx_debugfs_set, "%llu\n");
> +
> +static int ptdump_debugfs_init(void)
> +{
> +	debugfs_create_file("check_wx_pages", 0200, NULL, NULL, &check_wx_fops);
> +
> +	return 0;
> +}

Wouldn't it be better to have (only?) a readable attribute which triggers
this, and provides the result via this attribute?
That would allow for automated tests without having to parse dmesg.