linux-kernel - Re: [PATCH v2 3/3] Turn off test_uffdio_wp if CONFIG_PTE_MARKER_UFFD

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Date: Fri, 21 Jun 2024 17:27:43 -0400
From: Peter Xu <peterx@...hat.com>
To: Audra Mitchell <audra@...hat.com>
Cc: viro@...iv.linux.org.uk, brauner@...nel.org, jack@...e.cz,
	aarcange@...hat.com, akpm@...ux-foundation.org,
	rppt@...ux.vnet.ibm.com, shli@...com, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org, shuah@...nel.org,
	linux-kselftest@...r.kernel.org, raquini@...hat.com
Subject: Re: [PATCH v2 3/3] Turn off test_uffdio_wp if
 CONFIG_PTE_MARKER_UFFD_WP is not configured.

On Fri, Jun 21, 2024 at 02:12:24PM -0400, Audra Mitchell wrote:
> If CONFIG_PTE_MARKER_UFFD_WP is disabled, then testing with test_uffdio_up

Here you're talking about pte markers, then..

> enables calling uffdio_regsiter with the flag UFFDIO_REGISTER_MODE_WP. The
> kernel ensures in vma_can_userfault() that if CONFIG_PTE_MARKER_UFFD_WP
> is disabled, only allow the VM_UFFD_WP on anonymous vmas.
> 
> Signed-off-by: Audra Mitchell <audra@...hat.com>
> ---
>  tools/testing/selftests/mm/uffd-stress.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c
> index b9b6d858eab8..2601c9dfadd6 100644
> --- a/tools/testing/selftests/mm/uffd-stress.c
> +++ b/tools/testing/selftests/mm/uffd-stress.c
> @@ -419,6 +419,9 @@ static void parse_test_type_arg(const char *raw_type)
>  	test_uffdio_wp = test_uffdio_wp &&
>  		(features & UFFD_FEATURE_PAGEFAULT_FLAG_WP);
>  
> +	if (test_type != TEST_ANON && !(features & UFFD_FEATURE_WP_UNPOPULATED))
> +		test_uffdio_wp = false;

... here you're checking against wp_unpopulated.  I'm slightly confused.

Are you running this test over shmem/hugetlb when the WP feature isn't
supported?

I'm wondering whether you're looking for UFFD_FEATURE_WP_HUGETLBFS_SHMEM
instead.

Thanks,

> +
>  	close(uffd);
>  	uffd = -1;
>  }
> -- 
> 2.44.0
> 

-- 
Peter Xu