onnxruntime

8c650d81 - Fix XNNPACK Gemm SIGSEGV on missing and scalar 'C' bias (#28546)

Fix XNNPACK Gemm SIGSEGV on missing and scalar 'C' bias (#28546) ### Description Hardens the XNNPACK Gemm capability check against two SIGSEGV crashes during graph partitioning: one when the optional `C` input is omitted, one when `C` is a rank-0 (scalar) tensor. The check now guards the null `C` arg before calling `Shape()`, and rejects rank-0 `C` so the node falls back to the CPU EP cleanly. Thanks @kadu-v, the minimal Python repros made the root cause easy to confirm. Both reproduced as a hard crash on the first `InferenceSession` construction. ### Motivation and Context Fixes #28541 Fixes #28542 `Gemm::IsOnnxNodeSupported` dereferenced `C_arg->Shape()` without checking whether `C_arg` was non-null, so any Gemm without the optional bias segfaulted before the EP could decline the node. A rank-0 `C` then survived the existing checks and reached XNNPACK's fully-connected path, which doesn't implement scalar broadcast (there's already a TODO in that file noting it). That's the second SIGSEGV. ### Changes `onnxruntime/core/providers/xnnpack/math/gemm.cc`: - Null-check `C_arg` before reading its shape. Absent `C` is valid per the Gemm spec; treat it as "no bias". - Reject `C` with rank 0 from `IsOnnxNodeSupported` so the node falls through to CPU. Adding scalar broadcast support belongs with the TODO in the fully-connected path, not in the capability check. ### Testing Three regression tests in `onnxruntime/test/providers/xnnpack/xnnpack_basic_test.cc`: - `TestGemm_NoC_NoSegfault` builds a Gemm with the `C` input omitted. - `TestGemm_ScalarC_NoSegfault` builds a Gemm with a rank-0 `C`. - `TestGemm_EmptyC_NoSegfault` covers an empty-shape `C` edge case. Each test loads an `InferenceSession` with the XNNPACK EP registered and asserts no crash. I also suspect `Gemm`'s constructor has pre-existing crashes when `A` or `B` is 1-D, before the capability check even runs. Haven't reproduced it. Can file a follow-up if useful. Signed-off-by: Dhruvil <dhruvilparikh79@gmail.com>