Re: [PATCH v2] kasan: fix more unit tests with CONFIG_UBSAN_LOCAL_BOUNDS enabled

On Thu, Feb 24, 2022 at 1:20 AM Peter Collingbourne pcc@google.com wrote:

This is a followup to commit f649dc0e0d7b ("kasan: fix unit tests with CONFIG_UBSAN_LOCAL_BOUNDS enabled") that fixes tests that fail as a result of __alloc_size annotations being added to the kernel allocator functions.

Link: https://linux-review.googlesource.com/id/I4334cafc5db600fda5cebb851b2ee9fd09... Signed-off-by: Peter Collingbourne pcc@google.com Cc: stable@vger.kernel.org # 5.16.x Fixes: c37495d6254c ("slab: add __alloc_size attributes for better bounds checking")

---

v2:

• use OPTIMIZER_HIDE_VAR instead of volatile

lib/test_kasan.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/lib/test_kasan.c b/lib/test_kasan.c index 26a5c9007653..7c3dfb569445 100644 --- a/lib/test_kasan.c +++ b/lib/test_kasan.c @@ -185,6 +185,7 @@ static void kmalloc_pagealloc_oob_right(struct kunit *test) ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);

•   OPTIMIZER_HIDE_VAR(ptr);
    KUNIT_EXPECT_KASAN_FAIL(test, ptr[size + OOB_TAG_OFF] = 0);
  
    kfree(ptr);
  

@@ -295,6 +296,7 @@ static void krealloc_more_oob_helper(struct kunit *test, KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size2] = 'x');

    /* For all modes first aligned offset after size2 must be inaccessible. */

•   OPTIMIZER_HIDE_VAR(ptr2);
    KUNIT_EXPECT_KASAN_FAIL(test,
            ptr2[round_up(size2, KASAN_GRANULE_SIZE)] = 'x');
  
  

@@ -319,6 +321,8 @@ static void krealloc_less_oob_helper(struct kunit *test, /* Must be accessible for all modes. */ ptr2[size2 - 1] = 'x';

•   OPTIMIZER_HIDE_VAR(ptr2);
  

•   /* Generic mode is precise, so unaligned size2 must be inaccessible. */
    if (IS_ENABLED(CONFIG_KASAN_GENERIC))
            KUNIT_EXPECT_KASAN_FAIL(test, ptr2[size2] = 'x');
  

-- 2.35.1.473.g83b2b277ed-goog

Acked-by: Andrey Konovalov andreyknvl@gmail.com

This patch seems to be in partial conflict with the "kasan: test: Silence allocation warnings from GCC 12" patch by Kees, which is already in mm.

Thanks!