linux-kernel - Re: [PATCH v4 2/3] selftests: soft-dirty: Add test for mprotect

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Message-ID: <3b85bf1f-2383-7e26-c123-f300027bada0@redhat.com>
Date:   Mon, 25 Jul 2022 16:28:07 +0200
From:   David Hildenbrand <david@...hat.com>
To:     Peter Xu <peterx@...hat.com>, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org
Cc:     Nadav Amit <nadav.amit@...il.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v4 2/3] selftests: soft-dirty: Add test for mprotect

On 25.07.22 16:20, Peter Xu wrote:
> Add two soft-dirty test cases for mprotect() on both anon or file.
> 
> Signed-off-by: Peter Xu <peterx@...hat.com>
> ---
>  tools/testing/selftests/vm/soft-dirty.c | 67 ++++++++++++++++++++++++-
>  1 file changed, 66 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/vm/soft-dirty.c b/tools/testing/selftests/vm/soft-dirty.c
> index 08ab62a4a9d0..e3a43f5d4fa2 100644
> --- a/tools/testing/selftests/vm/soft-dirty.c
> +++ b/tools/testing/selftests/vm/soft-dirty.c
> @@ -121,13 +121,76 @@ static void test_hugepage(int pagemap_fd, int pagesize)
>  	free(map);
>  }
>  
> +static void test_mprotect(int pagemap_fd, int pagesize, bool anon)
> +{
> +	const char *type[] = {"file", "anon"};
> +	const char *fname = "./soft-dirty-test-file";
> +	int test_fd;
> +	char *map;
> +
> +	if (anon) {
> +		map = mmap(NULL, pagesize, PROT_READ|PROT_WRITE,
> +			   MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
> +		if (!map)
> +			ksft_exit_fail_msg("anon mmap failed\n");
> +	} else {
> +		test_fd = open(fname, O_RDWR | O_CREAT);
> +		if (test_fd < 0) {
> +			ksft_test_result_skip("Test %s open() file failed\n", __func__);
> +			return;
> +		}
> +		unlink(fname);
> +		ftruncate(test_fd, pagesize);
> +		map = mmap(NULL, pagesize, PROT_READ|PROT_WRITE,
> +			   MAP_SHARED, test_fd, 0);
> +		if (!map)
> +			ksft_exit_fail_msg("file mmap failed\n");
> +	}
> +
> +	*map = 1;
> +	ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1,
> +			 "Test %s-%s dirty bit of new written page\n",
> +			 __func__, type[anon]);
> +	clear_softdirty();
> +	ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0,
> +			 "Test %s-%s soft-dirty clear after clear_refs\n",
> +			 __func__, type[anon]);
> +	mprotect(map, pagesize, PROT_READ);
> +	ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0,
> +			 "Test %s-%s soft-dirty clear after marking RO\n",
> +			 __func__, type[anon]);
> +	mprotect(map, pagesize, PROT_READ|PROT_WRITE);
> +	ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 0,
> +			 "Test %s-%s soft-dirty clear after marking RW\n",
> +			 __func__, type[anon]);
> +	*map = 2;
> +	ksft_test_result(pagemap_is_softdirty(pagemap_fd, map) == 1,
> +			 "Test %s-%s soft-dirty after rewritten\n",
> +			 __func__, type[anon]);
> +
> +	munmap(map, pagesize);
> +
> +	if (!anon)
> +		close(test_fd);
> +}
> +
> +static void test_mprotect_anon(int pagemap_fd, int pagesize)
> +{
> +	test_mprotect(pagemap_fd, pagesize, true);
> +}
> +
> +static void test_mprotect_file(int pagemap_fd, int pagesize)
> +{
> +	test_mprotect(pagemap_fd, pagesize, false);
> +}
> +
>  int main(int argc, char **argv)
>  {
>  	int pagemap_fd;
>  	int pagesize;
>  
>  	ksft_print_header();
> -	ksft_set_plan(5);
> +	ksft_set_plan(15);
>  
>  	pagemap_fd = open(PAGEMAP_FILE_PATH, O_RDONLY);
>  	if (pagemap_fd < 0)
> @@ -138,6 +201,8 @@ int main(int argc, char **argv)
>  	test_simple(pagemap_fd, pagesize);
>  	test_vma_reuse(pagemap_fd, pagesize);
>  	test_hugepage(pagemap_fd, pagesize);
> +	test_mprotect_anon(pagemap_fd, pagesize);
> +	test_mprotect_file(pagemap_fd, pagesize);
>  
>  	close(pagemap_fd);
>  

Reviewed-by: David Hildenbrand <david@...hat.com>

-- 
Thanks,

David / dhildenb