Commit 0389c305 authored by Lance Yang's avatar Lance Yang Committed by Andrew Morton
Browse files

selftests/mm: skip soft-dirty tests when CONFIG_MEM_SOFT_DIRTY is disabled 

The madv_populate and soft-dirty kselftests currently fail on systems
where CONFIG_MEM_SOFT_DIRTY is disabled.

Introduce a new helper softdirty_supported() into vm_util.c/h to ensure
tests are properly skipped when the feature is not enabled.

Link: https://lkml.kernel.org/r/20250917133137.62802-1-lance.yang@linux.dev


Fixes: 9f3265db ("selftests: vm: add test for Soft-Dirty PTE bit")
Signed-off-by: default avatarLance Yang <lance.yang@linux.dev>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Suggested-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Gabriel Krisman Bertazi <krisman@collabora.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 8d009da3

tools/testing/selftests/mm/madv_populate.c

+2 −19
Original line number Diff line number Diff line
@@ -264,23 +264,6 @@ static void test_softdirty(void) 
	munmap(addr, SIZE);

}



static int system_has_softdirty(void)

{

	/*

	 * There is no way to check if the kernel supports soft-dirty, other

	 * than by writing to a page and seeing if the bit was set. But the

	 * tests are intended to check that the bit gets set when it should, so

	 * doing that check would turn a potentially legitimate fail into a

	 * skip. Fortunately, we know for sure that arm64 does not support

	 * soft-dirty. So for now, let's just use the arch as a corse guide.

	 */

#if defined(__aarch64__)

	return 0;

#else

	return 1;

#endif

}



int main(int argc, char **argv)

{

	int nr_tests = 16;
@@ -288,7 +271,7 @@ int main(int argc, char **argv) 


	pagesize = getpagesize();



	if (system_has_softdirty())

	if (softdirty_supported())

		nr_tests += 5;



	ksft_print_header();
@@ -300,7 +283,7 @@ int main(int argc, char **argv) 
	test_holes();

	test_populate_read();

	test_populate_write();

	if (system_has_softdirty())

	if (softdirty_supported())

		test_softdirty();



	err = ksft_get_fail_cnt();

tools/testing/selftests/mm/soft-dirty.c

+4 −1
Original line number Diff line number Diff line
@@ -200,8 +200,11 @@ int main(int argc, char **argv) 
	int pagesize;



	ksft_print_header();

	ksft_set_plan(15);



	if (!softdirty_supported())

		ksft_exit_skip("soft-dirty is not support\n");



	ksft_set_plan(15);

	pagemap_fd = open(PAGEMAP_FILE_PATH, O_RDONLY);

	if (pagemap_fd < 0)

		ksft_exit_fail_msg("Failed to open %s\n", PAGEMAP_FILE_PATH);

tools/testing/selftests/mm/vm_util.c

+17 −0
Original line number Diff line number Diff line
@@ -449,6 +449,23 @@ bool check_vmflag_pfnmap(void *addr) 
	return check_vmflag(addr, "pf");

}



bool softdirty_supported(void)

{

	char *addr;

	bool supported = false;

	const size_t pagesize = getpagesize();



	/* New mappings are expected to be marked with VM_SOFTDIRTY (sd). */

	addr = mmap(0, pagesize, PROT_READ | PROT_WRITE,

		    MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);

	if (!addr)

		ksft_exit_fail_msg("mmap failed\n");



	supported = check_vmflag(addr, "sd");

	munmap(addr, pagesize);

	return supported;

}



/*

 * Open an fd at /proc/$pid/maps and configure procmap_out ready for

 * PROCMAP_QUERY query. Returns 0 on success, or an error code otherwise.

tools/testing/selftests/mm/vm_util.h

+1 −0
Original line number Diff line number Diff line
@@ -104,6 +104,7 @@ bool find_vma_procmap(struct procmap_fd *procmap, void *address); 
int close_procmap(struct procmap_fd *procmap);

int write_sysfs(const char *file_path, unsigned long val);

int read_sysfs(const char *file_path, unsigned long *val);

bool softdirty_supported(void);



static inline int open_self_procmap(struct procmap_fd *procmap_out)

{