Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
New issues: - [Medium] The newly added test_dedup_empty KUnit test will unconditionally fail, breaking CI. Pre-existing issues: - [Critical] dma_fence_dedup_array() incorrectly returns 1 for an empty array, causing uninitialized memory dereference in amdgpu_userq_wait_return_fence_info(). -- commit 693b63d34624f1aa69f2c97819d4a6d6655ec6bc Author: Baineng Shou <[email protected]> dma-buf/test: add KUnit case for dma_fence_dedup_array() empty input This commit adds a KUnit test case to verify that dma_fence_dedup_array() returns 0 when provided with an empty array. The test aims to ensure the documented contract is enforced and prevents future regressions. > diff --git a/drivers/dma-buf/st-dma-fence-unwrap.c > b/drivers/dma-buf/st-dma-fence-unwrap.c > index 4e7ee25372ba6..72dea6091d583 100644 > --- a/drivers/dma-buf/st-dma-fence-unwrap.c > +++ b/drivers/dma-buf/st-dma-fence-unwrap.c [ ... ] > @@ -370,6 +370,15 @@ static void test_unwrap_merge_seqno(struct kunit *test) > dma_fence_put(f1); > } > > +static void test_dedup_empty(struct kunit *test) > +{ > + struct dma_fence *fence[1] = { NULL }; > + int ret; > + > + ret = dma_fence_dedup_array(fence, 0); > + KUNIT_EXPECT_EQ(test, ret, 0); [Severity: Medium] Will this test fail unconditionally on the current tree? Looking at dma_fence_dedup_array() in drivers/dma-buf/dma-fence-unwrap.c, there is no early return for an empty array: int dma_fence_dedup_array(struct dma_fence **fences, int num_fences) { int i, j; sort(fences, num_fences, sizeof(*fences), fence_cmp, NULL); j = 0; for (i = 1; i < num_fences; i++) { ... } return ++j; } The loop condition i < num_fences is skipped when num_fences is 0, but the function ends with return ++j, which returns 1. Since this patch adds a KUnit expectation for 0, won't this cause CI to break until the corresponding fix for dma_fence_dedup_array() is actually applied to the tree? [Severity: Critical] This is a pre-existing issue, but does dma_fence_dedup_array() returning 1 for empty arrays cause an uninitialized memory dereference in other subsystems? For example, in drivers/gpu/drm/amd/amdgpu/amdgpu_userq_fence.c: amdgpu_userq_wait_return_fence_info() uses kmalloc_array for the fences array and eventually calls dma_fence_dedup_array: num_fences = dma_fence_dedup_array(fences, num_fences); waitq = amdgpu_userq_get(userq_mgr, wait_info->waitq_id); if (!waitq) { ... for (i = 0, cnt = 0; i < num_fences; i++) { struct amdgpu_userq_fence_driver *fence_drv; struct amdgpu_userq_fence *userq_fence; u32 index; userq_fence = to_amdgpu_userq_fence(fences[i]); If an unprivileged user triggers a path via ioctl where 0 fences are populated but dma_fence_dedup_array() is called with num_fences = 0, returning 1 will cause the subsequent loop to iterate once. Will this dereference an uninitialized garbage pointer from kmalloc_array() when to_amdgpu_userq_fence() evaluates fences[i]? > +} > + > static void test_unwrap_merge_order(struct kunit *test) [ ... ] -- Sashiko AI review · https://sashiko.dev/#/patchset/[email protected]?part=1
