Whisper.cpp 1.7.1: Crash on Simulator in ggml-metal.m:3283, trying to access MTLDevice

[zapsleep]

We started having crashes since version 1.7.1 (didn't check 1.7.0 though) when using Whisper.cpp on Simulator or Preview.
It crashes in ggml-metal.m on line 3283:

ctx->buffers[0].metal = [device newBufferWithBytesNoCopy:ctx->all_data
                            length:size_aligned
                            options:MTLResourceStorageModeShared
                            deallocator:nil];

I'm not familiar with Metal too much but it looks like it tries to work with a GPU device while Simulator doesn't have one? Explicitly setting context_parameters.use_gpu = false solves the issue. But it switched to CPU-only automatically on versions prior to 1.7.1 (or 1.7.0).

Tested on iOS 17.5 and 18.x simulator runtimes. Xcode 16.0, macOS 15.0.1.

Stack trace:

Thread 12 Queue : com.apple.root.user-initiated-qos.cooperative (concurrent)
#0	0x00000001800dd63c in _xpc_api_misuse ()
#1	0x00000001800d3cd4 in _xpc_shmem_create_with_prot ()
#2	0x0000000226ef63f8 in -[MTLSimDevice newBufferWithLength:options:pointer:copyBytes:deallocator:] ()
#3	0x00000001c5127c48 in -[MTLDebugDevice newBufferWithBytesNoCopy:length:options:deallocator:] ()
#4	0x000000010424b824 in ggml_backend_metal_buffer_type_alloc_buffer at ggml-metal.m:3283
#5	0x0000000104243b80 in alloc_tensor_range at ggml-alloc.c:940
#6	0x0000000104243ab8 in ggml_backend_alloc_ctx_tensors_from_buft at ggml-alloc.c:1018
#7	0x00000001042d26a0 in whisper_model_load at whisper.cpp:1799
#8	0x00000001042cea54 in ::whisper_init_with_params_no_state(whisper_model_loader *, whisper_context_params) at whisper.cpp:3659
#9	0x00000001042ce7cc in ::whisper_init_from_file_with_params_no_state(const char *, whisper_context_params) at whisper.cpp:3597
#10	0x00000001042d34a4 in ::whisper_init_from_file_with_params(const char *, whisper_context_params) at whisper.cpp:3672
#11	0x00000001038a5508 in <redacted>
#12	0x00000001039e9be4 in <redacted>
#13	0x00000001039f0558 in <redacted>
#14	0x000000010393503c in <redacted>
#15	0x0000000103932ab4 in <redacted>
#16	0x0000000103b12784 in closure #1 in <redacted>
#17	0x0000000103b258f4 in partial apply for closure #1 in <redacted> ()
#18	0x0000000103777b40 in thunk for @escaping @isolated(any) @callee_guaranteed @async () -> (@out A) ()
#19	0x0000000103779728 in partial apply for thunk for @escaping @isolated(any) @callee_guaranteed @async () -> (@out A) ()

[ggerganov]

Can you check if this works on latest master?

[zapsleep]

Checked on 0377596 (currently latest)
Got the same crash. Stack trace below:

Thread 3 Queue : com.apple.root.user-initiated-qos.cooperative (concurrent)
#0	0x00000001800dd5dc in _xpc_api_misuse ()
#1	0x00000001800d3c74 in _xpc_shmem_create_with_prot ()
#2	0x00000002275c03f8 in -[MTLSimDevice newBufferWithLength:options:pointer:copyBytes:deallocator:] ()
#3	0x00000001c5788af0 in -[MTLDebugDevice newBufferWithBytesNoCopy:length:options:deallocator:] ()
#4	0x00000001062d82e0 in ggml_backend_metal_buffer_type_alloc_buffer at ggml-metal.m:3378
#5	0x00000001062d0580 in alloc_tensor_range at ggml-alloc.c:938
#6	0x00000001062d04b8 in ggml_backend_alloc_ctx_tensors_from_buft at ggml-alloc.c:1016
#7	0x000000010635f56c in whisper_model_load at whisper.cpp:1803
#8	0x000000010635b920 in ::whisper_init_with_params_no_state(whisper_model_loader *, whisper_context_params) at whisper.cpp:3676
#9	0x000000010635b680 in ::whisper_init_from_file_with_params_no_state(const char *, whisper_context_params) at whisper.cpp:3611
#10	0x0000000106360370 in ::whisper_init_from_file_with_params(const char *, whisper_context_params) at whisper.cpp:3689
#11	0x0000000105931f74 in <redacted>
#12	0x0000000105a76650 in <redacted>
#13	0x0000000105a7cfc4 in <redacted>
#14	0x00000001059c1aa8 in <redacted>
#15	0x00000001059bf520 in <redacted>
#16	0x0000000105b9f1f0 in closure #1 in <redacted>
#17	0x0000000105bb2360 in partial apply for closure #1 in <redacted>
#18	0x00000001058045ac in thunk for @escaping @isolated(any) @callee_guaranteed @async () -> (@out A) ()
#19	0x0000000105806194 in partial apply for thunk for @escaping @isolated(any) @callee_guaranteed @async () -> (@out A) ()