Commit f6dd4e22 authored by Ryan Roberts's avatar Ryan Roberts Committed by Andrew Morton
Browse files

selftests/mm: skip soft-dirty tests on arm64 

arm64 does not support the soft-dirty PTE bit.  However, the `soft-dirty`
test suite is currently run unconditionally and therefore generates
spurious test failures on arm64.  There are also some tests in
`madv_populate` which assume it is supported.

For `soft-dirty` lets disable the whole suite for arm64; it is no longer
built and run_vmtests.sh will skip it if its not present.

For `madv_populate`, we need a runtime mechanism so that the remaining
tests continue to be run.  Unfortunately, the only way to determine if the
soft-dirty dirty bit is supported is to write to a page, then see if the
bit is set in /proc/self/pagemap.  But the tests that we want to
conditionally execute are testing precicesly this.  So if we introduced
this feature check, we could accedentally turn a real failure (on a system
that claims to support soft-dirty) into a skip.  So instead, do the check
based on architecture; for arm64, we report that soft-dirty is not
supported.

Link: https://lkml.kernel.org/r/20230724082522.1202616-3-ryan.roberts@arm.com


Signed-off-by: default avatarRyan Roberts <ryan.roberts@arm.com>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 58e2847a

tools/testing/selftests/mm/Makefile

+4 −1
Original line number Diff line number Diff line
@@ -64,12 +64,15 @@ TEST_GEN_PROGS += thuge-gen 
TEST_GEN_PROGS += transhuge-stress

TEST_GEN_PROGS += uffd-stress

TEST_GEN_PROGS += uffd-unit-tests

TEST_GEN_PROGS += soft-dirty

TEST_GEN_PROGS += split_huge_page_test

TEST_GEN_PROGS += ksm_tests

TEST_GEN_PROGS += ksm_functional_tests

TEST_GEN_PROGS += mdwe_test



ifneq ($(ARCH),arm64)

TEST_GEN_PROGS += soft-dirty

endif



ifeq ($(ARCH),x86_64)

CAN_BUILD_I386 := $(shell ./../x86/check_cc.sh "$(CC)" ../x86/trivial_32bit_program.c -m32)

CAN_BUILD_X86_64 := $(shell ./../x86/check_cc.sh "$(CC)" ../x86/trivial_64bit_program.c)

tools/testing/selftests/mm/madv_populate.c

+24 −2
Original line number Diff line number Diff line
@@ -264,14 +264,35 @@ 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;

	int err;



	pagesize = getpagesize();



	if (system_has_softdirty())

		nr_tests += 5;



	ksft_print_header();

	ksft_set_plan(21);

	ksft_set_plan(nr_tests);



	sense_support();

	test_prot_read();
@@ -279,6 +300,7 @@ int main(int argc, char **argv) 
	test_holes();

	test_populate_read();

	test_populate_write();

	if (system_has_softdirty())

		test_softdirty();



	err = ksft_get_fail_cnt();

tools/testing/selftests/mm/run_vmtests.sh

+4 −1
Original line number Diff line number Diff line
@@ -322,7 +322,10 @@ then 
	CATEGORY="pkey" run_test ./protection_keys_64

fi



if [ -x ./soft-dirty ]

then

	CATEGORY="soft_dirty" run_test ./soft-dirty

fi



# COW tests

CATEGORY="cow" run_test ./cow