Commit 7005e7ec authored by Brian Johannesmeyer's avatar Brian Johannesmeyer Committed by Andrew Morton
Browse files

kmsan: introduce test_unpoison_memory() 

Add a regression test to ensure that kmsan_unpoison_memory() works the
same as an unpoisoning operation added by the instrumentation.

The test has two subtests: one that checks the instrumentation, and one
that checks kmsan_unpoison_memory().  Each subtest initializes the first
byte of a 4-byte buffer, then checks that the other 3 bytes are
uninitialized.

[glider@google.com: change description, remove comment about failing test case]
Link: https://lkml.kernel.org/r/20240528104807.738758-2-glider@google.com


Signed-off-by: default avatarBrian Johannesmeyer <bjohannesmeyer@gmail.com>
Link: https://lore.kernel.org/lkml/20240524232804.1984355-1-bjohannesmeyer@gmail.com/T/


Signed-off-by: default avatarAlexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent f56810c9

mm/kmsan/kmsan_test.c

+27 −0
Original line number Diff line number Diff line
@@ -614,6 +614,32 @@ static void test_stackdepot_roundtrip(struct kunit *test) 
	KUNIT_EXPECT_TRUE(test, report_matches(&expect));

}



/*

 * Test case: ensure that kmsan_unpoison_memory() and the instrumentation work

 * the same.

 */

static void test_unpoison_memory(struct kunit *test)

{

	EXPECTATION_UNINIT_VALUE_FN(expect, "test_unpoison_memory");

	volatile char a[4], b[4];



	kunit_info(

		test,

		"unpoisoning via the instrumentation vs. kmsan_unpoison_memory() (2 UMR reports)\n");



	/* Initialize a[0] and check a[1]--a[3]. */

	a[0] = 0;

	kmsan_check_memory((char *)&a[1], 3);

	KUNIT_EXPECT_TRUE(test, report_matches(&expect));



	report_reset();



	/* Initialize b[0] and check b[1]--b[3]. */

	kmsan_unpoison_memory((char *)&b[0], 1);

	kmsan_check_memory((char *)&b[1], 3);

	KUNIT_EXPECT_TRUE(test, report_matches(&expect));

}



static struct kunit_case kmsan_test_cases[] = {

	KUNIT_CASE(test_uninit_kmalloc),

	KUNIT_CASE(test_init_kmalloc),
@@ -637,6 +663,7 @@ static struct kunit_case kmsan_test_cases[] = { 
	KUNIT_CASE(test_memset64),

	KUNIT_CASE(test_long_origin_chain),

	KUNIT_CASE(test_stackdepot_roundtrip),

	KUNIT_CASE(test_unpoison_memory),

	{},

};