Since the hardware tag-based KASAN mode might not have a redzone that comes after an allocated object (when kasan.mode=prod is enabled), the kasan_bitops_tags() test ends up corrupting the next object in memory.
Change the test so it always accesses the redzone that lies within the allocated object's boundaries. Signed-off-by: Andrey Konovalov <andreyk...@google.com> Link: https://linux-review.googlesource.com/id/I67f51d1ee48f0a8d0fe2658c2a39e4879fe0832a --- lib/test_kasan.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/lib/test_kasan.c b/lib/test_kasan.c index b67da7f6e17f..3ea52da52714 100644 --- a/lib/test_kasan.c +++ b/lib/test_kasan.c @@ -771,17 +771,17 @@ static void kasan_bitops_tags(struct kunit *test) /* This test is specifically crafted for the tag-based mode. */ if (IS_ENABLED(CONFIG_KASAN_GENERIC)) { - kunit_info(test, "skipping, CONFIG_KASAN_SW_TAGS required"); + kunit_info(test, "skipping, CONFIG_KASAN_SW/HW_TAGS required"); return; } - /* Allocation size will be rounded to up granule size, which is 16. */ - bits = kzalloc(sizeof(*bits), GFP_KERNEL); + /* kmalloc-64 cache will be used and the last 16 bytes will be the redzone. */ + bits = kzalloc(48, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, bits); - /* Do the accesses past the 16 allocated bytes. */ - kasan_bitops_modify(test, BITS_PER_LONG, &bits[1]); - kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, &bits[1]); + /* Do the accesses past the 48 allocated bytes, but within the redone. */ + kasan_bitops_modify(test, BITS_PER_LONG, (void *)bits + 48); + kasan_bitops_test_and_modify(test, BITS_PER_LONG + BITS_PER_BYTE, (void *)bits + 48); kfree(bits); } -- 2.29.2.729.g45daf8777d-goog
