Add kunit tests that exercise edge cases where allocation requests exceed mm->max_order after rounding. This can happen with non-power-of-two VRAM sizes when the allocator rounds up requests.
For example, with 10G VRAM (8G + 2G roots), mm->max_order represents the 8G block. A 9G allocation can round up to 16G in multiple ways: CONTIGUOUS allocation rounds to next power-of-two, or non-CONTIGUOUS with 8G min_block_size rounds to next alignment boundary. The test validates CONTIGUOUS and RANGE flag combinations, ensuring that only CONTIGUOUS-alone allocations use try_harder fallback, while other combinations return -EINVAL when rounded size exceeds memory, preventing BUG_ON assertions. Cc: Christian König <[email protected]> Cc: Arunpravin Paneer Selvam <[email protected]> Suggested-by: Matthew Auld <[email protected]> Signed-off-by: Sanjay Yadav <[email protected]> --- drivers/gpu/drm/tests/drm_buddy_test.c | 35 ++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/drivers/gpu/drm/tests/drm_buddy_test.c b/drivers/gpu/drm/tests/drm_buddy_test.c index 5f40b5343bd8..e6f8459c6c54 100644 --- a/drivers/gpu/drm/tests/drm_buddy_test.c +++ b/drivers/gpu/drm/tests/drm_buddy_test.c @@ -857,6 +857,40 @@ static void drm_test_buddy_alloc_limit(struct kunit *test) drm_buddy_fini(&mm); } +static void drm_test_buddy_alloc_exceeds_max_order(struct kunit *test) +{ + u64 mm_size = SZ_8G + SZ_2G, size = SZ_8G + SZ_1G, min_block_size = SZ_8G; + struct drm_buddy mm; + LIST_HEAD(blocks); + int err; + + KUNIT_ASSERT_FALSE_MSG(test, drm_buddy_init(&mm, mm_size, SZ_4K), + "buddy_init failed\n"); + + /* CONTIGUOUS allocation should succeed via try_harder fallback */ + KUNIT_ASSERT_FALSE_MSG(test, drm_buddy_alloc_blocks(&mm, 0, mm_size, size, + SZ_4K, &blocks, + DRM_BUDDY_CONTIGUOUS_ALLOCATION), + "buddy_alloc hit an error size=%llu\n", size); + drm_buddy_free_list(&mm, &blocks, 0); + + /* Non-CONTIGUOUS with large min_block_size should return -EINVAL */ + err = drm_buddy_alloc_blocks(&mm, 0, mm_size, size, min_block_size, &blocks, 0); + KUNIT_EXPECT_EQ(test, err, -EINVAL); + + /* Non-CONTIGUOUS + RANGE with large min_block_size should return -EINVAL */ + err = drm_buddy_alloc_blocks(&mm, 0, mm_size, size, min_block_size, &blocks, + DRM_BUDDY_RANGE_ALLOCATION); + KUNIT_EXPECT_EQ(test, err, -EINVAL); + + /* CONTIGUOUS + RANGE should return -EINVAL (no try_harder for RANGE) */ + err = drm_buddy_alloc_blocks(&mm, 0, mm_size, size, SZ_4K, &blocks, + DRM_BUDDY_CONTIGUOUS_ALLOCATION | DRM_BUDDY_RANGE_ALLOCATION); + KUNIT_EXPECT_EQ(test, err, -EINVAL); + + drm_buddy_fini(&mm); +} + static int drm_buddy_suite_init(struct kunit_suite *suite) { while (!random_seed) @@ -877,6 +911,7 @@ static struct kunit_case drm_buddy_tests[] = { KUNIT_CASE(drm_test_buddy_alloc_clear), KUNIT_CASE(drm_test_buddy_alloc_range_bias), KUNIT_CASE(drm_test_buddy_fragmentation_performance), + KUNIT_CASE(drm_test_buddy_alloc_exceeds_max_order), {} }; -- 2.52.0
