Commit 6204c9ab authored by Alexander Potapenko's avatar Alexander Potapenko Committed by Andrew Morton
Browse files

kmsan: add test_stackdepot_roundtrip 

Ensure that KMSAN does not report false positives in instrumented callers
of stack_depot_save(), stack_depot_print(), and stack_depot_fetch().

Link: https://lkml.kernel.org/r/20230306111322.205724-2-glider@google.com


Signed-off-by: default avatarAlexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: syzbot <syzkaller@googlegroups.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 8e00b2df

mm/kmsan/kmsan_test.c

+31 −0
Original line number Diff line number Diff line
@@ -551,6 +551,36 @@ static void test_long_origin_chain(struct kunit *test) 
	KUNIT_EXPECT_TRUE(test, report_matches(&expect));

}



/*

 * Test case: ensure that saving/restoring/printing stacks to/from stackdepot

 * does not trigger errors.

 *

 * KMSAN uses stackdepot to store origin stack traces, that's why we do not

 * instrument lib/stackdepot.c. Yet it must properly mark its outputs as

 * initialized because other kernel features (e.g. netdev tracker) may also

 * access stackdepot from instrumented code.

 */

static void test_stackdepot_roundtrip(struct kunit *test)

{

	unsigned long src_entries[16], *dst_entries;

	unsigned int src_nentries, dst_nentries;

	EXPECTATION_NO_REPORT(expect);

	depot_stack_handle_t handle;



	kunit_info(test, "testing stackdepot roundtrip (no reports)\n");



	src_nentries =

		stack_trace_save(src_entries, ARRAY_SIZE(src_entries), 1);

	handle = stack_depot_save(src_entries, src_nentries, GFP_KERNEL);

	stack_depot_print(handle);

	dst_nentries = stack_depot_fetch(handle, &dst_entries);

	KUNIT_EXPECT_TRUE(test, src_nentries == dst_nentries);



	kmsan_check_memory((void *)dst_entries,

			   sizeof(*dst_entries) * dst_nentries);

	KUNIT_EXPECT_TRUE(test, report_matches(&expect));

}



static struct kunit_case kmsan_test_cases[] = {

	KUNIT_CASE(test_uninit_kmalloc),

	KUNIT_CASE(test_init_kmalloc),
@@ -573,6 +603,7 @@ static struct kunit_case kmsan_test_cases[] = { 
	KUNIT_CASE(test_memset32),

	KUNIT_CASE(test_memset64),

	KUNIT_CASE(test_long_origin_chain),

	KUNIT_CASE(test_stackdepot_roundtrip),

	{},

};