Il2cpp crashing...

[kamyker]

I'm not sure what happens but game built with il2cpp crashes overtime when Unity tries to allocate something big like float[]. Are all pointers allocated correctly? I think it crashes when Unity tried to use the same memory that's used by ilruntime.

The end of stacktrace is always:

Stack Trace of Crashed Thread 87940:
0x00007FF9BB87C36A (GameAssembly) [C:\Program Files\Unity\Hub\Editor\2020.3.14f1\Editor\Data\il2cpp\libil2cpp\os\Win32\Assert.cpp:12] il2cpp_assert 
0x00007FF9BB9E4306 (GameAssembly) [C:\Program Files\Unity\Hub\Editor\2020.3.14f1\Editor\Data\il2cpp\libil2cpp\gc\BoehmGC.cpp:67] GC_gcj_vector_proc 
0x00007FF9BB995B07 (GameAssembly) [C:\Program Files\Unity\Hub\Editor\2020.3.14f1\Editor\Data\il2cpp\external\bdwgc\mark.c:782] GC_mark_from 
0x00007FF9BB9966D3 (GameAssembly) [C:\Program Files\Unity\Hub\Editor\2020.3.14f1\Editor\Data\il2cpp\external\bdwgc\mark.c:361] GC_mark_some_inner 
0x00007FF9BB9964FA (GameAssembly) [C:\Program Files\Unity\Hub\Editor\2020.3.14f1\Editor\Data\il2cpp\external\bdwgc\mark.c:506] GC_mark_some 
0x00007FF9BB99F037 (GameAssembly) [C:\Program Files\Unity\Hub\Editor\2020.3.14f1\Editor\Data\il2cpp\external\bdwgc\alloc.c:832] GC_stopped_mark 
0x00007FF9BB99FB6B (GameAssembly) [C:\Program Files\Unity\Hub\Editor\2020.3.14f1\Editor\Data\il2cpp\external\bdwgc\alloc.c:580] GC_try_to_collect_inner 
0x00007FF9BB98A601 (GameAssembly) [C:\Program Files\Unity\Hub\Editor\2020.3.14f1\Editor\Data\il2cpp\external\bdwgc\alloc.c:1484] GC_collect_or_expand 
0x00007FF9BB9884DE (GameAssembly) [C:\Program Files\Unity\Hub\Editor\2020.3.14f1\Editor\Data\il2cpp\external\bdwgc\alloc.c:1579] GC_allocobj 
0x00007FF9BB99022D (GameAssembly) [C:\Program Files\Unity\Hub\Editor\2020.3.14f1\Editor\Data\il2cpp\external\bdwgc\malloc.c:191] GC_generic_malloc_inner 
0x00007FF9BB98FC3F (GameAssembly) [C:\Program Files\Unity\Hub\Editor\2020.3.14f1\Editor\Data\il2cpp\external\bdwgc\malloc.c:251] GC_generic_malloc 
0x00007FF9BB994B8D (GameAssembly) [C:\Program Files\Unity\Hub\Editor\2020.3.14f1\Editor\Data\il2cpp\external\bdwgc\malloc.c:327] GC_malloc_kind_global 
0x00007FF9BB994A3C (GameAssembly) [C:\Program Files\Unity\Hub\Editor\2020.3.14f1\Editor\Data\il2cpp\external\bdwgc\malloc.c:334] GC_malloc_kind 
0x00007FF9BB9946C6 (GameAssembly) [C:\Program Files\Unity\Hub\Editor\2020.3.14f1\Editor\Data\il2cpp\external\bdwgc\malloc.c:342] GC_malloc_atomic 

[liiir1985]

ILRuntime is purely implemented in c#, so basically it has no difference between it and your game code written in Unity, all memories allocated by ilruntime is using the common way which people would do with ordinary c# code with only 1 exception, the evaluation stack( inside RuntimeStack class, but it has nothing to do with boehm gc, it won't touch such memory). This crash may be engine version related, have you tried with another unity version? The known pattern of random crash with il2cpp is if you build the game with debug profile for c++/ xcode, the game would crash when the call stack gets deep due to stack overflow.

[liiir1985]

Besides, since the source code of il2cpp is avaliable, so you can try debug your game with visual studio, when it crashes, it'll stop at BoehmGC.cpp:67, so you can check out why it failed to read the class's value type

[kamyker]

Crash at something like: var arr = new float[bignumber]; then:

 	GameAssembly.dll!il2cpp_assert(const char * assertion, const char * file, unsigned int line) Line 12	C++
>	GameAssembly.dll!GC_gcj_vector_proc(unsigned __int64 * addr, GC_ms_entry * mark_stack_ptr, GC_ms_entry * mark_stack_limit, unsigned __int64 env) Line 67	C++
 	GameAssembly.dll!GC_mark_from(GC_ms_entry * mark_stack_top, GC_ms_entry * mark_stack, GC_ms_entry * mark_stack_limit) Line 782	C
 	GameAssembly.dll!GC_mark_some_inner(char * cold_gc_frame) Line 361	C
 	GameAssembly.dll!GC_mark_some(char * cold_gc_frame) Line 506	C
 	GameAssembly.dll!GC_stopped_mark(int(*)() stop_func) Line 832	C
 	GameAssembly.dll!GC_try_to_collect_inner(int(*)() stop_func) Line 580	C
 	GameAssembly.dll!GC_collect_or_expand(unsigned __int64 needed_blocks, int ignore_off_page, int retry) Line 1484	C
 	GameAssembly.dll!GC_alloc_large(unsigned __int64 lb, int k, unsigned int flags) Line 64	C
 	GameAssembly.dll!GC_generic_malloc(unsigned __int64 lb, int k) Line 264	C
 	GameAssembly.dll!GC_malloc_kind_global(unsigned __int64 lb, int k) Line 327	C
 	GameAssembly.dll!GC_malloc_kind(unsigned __int64 lb, int k) Line 334	C
 	GameAssembly.dll!GC_malloc_atomic(unsigned __int64 lb) Line 342	C
 	GameAssembly.dll!il2cpp::vm::Object::AllocatePtrFree(unsigned __int64 size, Il2CppClass * typeInfo) Line 67	C++
 	GameAssembly.dll!il2cpp::vm::Array::NewSpecific(Il2CppClass * klass, unsigned __int64 n) Line 128	C++
 	GameAssembly.dll!SZArrayNew(Il2CppClass * arrayType, unsigned int length) Line 121	C++

	Name	Value	Type
◢	element_type	0x0000018dd9b08310 {image=0x0000018cf9031be8 {name=0x0000018cf96195cc "System.Collections.Immutable.dll" ...} ...}	Il2CppClass *
	▶ image	0x0000018cf9031be8 {name=0x0000018cf96195cc "System.Collections.Immutable.dll" nameNoExt=0x0000018cf9034cb0 "System.Collections.Immutable" ...}	const Il2CppImage *
	gc_desc	0x0000000000000008	void *
	▶ name	0x0000018cf9619ea6 "ImmutableArray`1"	const char *
	▶ namespaze	0x0000018cf961950b "System.Collections.Immutable"	const char *
	▶ byval_arg	{data={dummy=0x00007fffbc1a1380 {GameAssembly.dll!Il2CppGenericClass ImmutableArray_1_tC4DBABD9A1FC859F88C2E53876452E133A0845C1_GenericClass} ...} ...}	Il2CppType
	▶ this_arg	{data={dummy=0x00007fffbc1a1380 {GameAssembly.dll!Il2CppGenericClass ImmutableArray_1_tC4DBABD9A1FC859F88C2E53876452E133A0845C1_GenericClass} ...} ...}	Il2CppType
	▶ element_class	0x0000018dd9b08310 {image=0x0000018cf9031be8 {name=0x0000018cf96195cc "System.Collections.Immutable.dll" ...} ...}	Il2CppClass *
	▶ castClass	0x0000018dd9b08310 {image=0x0000018cf9031be8 {name=0x0000018cf96195cc "System.Collections.Immutable.dll" ...} ...}	Il2CppClass *
	▶ declaringType	0x0000000000000000	Il2CppClass *
	▶ parent	0x0000018cf9205c90 {image=0x0000018cf9030eb0 {name=0x0000018cf954d0c5 "mscorlib.dll" nameNoExt=0x0000018cf8fa0470 "mscorlib" ...} ...}	Il2CppClass *
	▶ generic_class	0x00007fffbc1a1380 {GameAssembly.dll!Il2CppGenericClass ImmutableArray_1_tC4DBABD9A1FC859F88C2E53876452E133A0845C1_GenericClass} {...}	Il2CppGenericClass *
	typeMetadataHandle	0x0000000000000000	const ___Il2CppMetadataTypeHandle *
	▶ interopData	0x0000000000000000	const Il2CppInteropData *
	▶ klass	0x0000018dd9b08310 {image=0x0000018cf9031be8 {name=0x0000018cf96195cc "System.Collections.Immutable.dll" ...} ...}	Il2CppClass *
	▶ fields	0x0000018dd9b0ab30 {name=0x0000018cf9551ae2 "Empty" type=0x0000018dd9b0ab70 {data={dummy=0x00007fffbc1a1380 {GameAssembly.dll!Il2CppGenericClass ImmutableArray_1_tC4DBABD9A1FC859F88C2E53876452E133A0845C1_GenericClass} ...} ...} ...}	FieldInfo *
	▶ events	0x0000000000000000	const EventInfo *
	▶ properties	0x0000018dd9b116d8 {parent=0x0000018dd9b08310 {image=0x0000018cf9031be8 {name=0x0000018cf96195cc "System.Collections.Immutable.dll" ...} ...} ...}	const PropertyInfo *
	▶ methods	0x0000018dd9b0b500 {0x0000018dd9b0b720 {methodPointer=0x00007fffae240ac0 {GameAssembly.dll!ImmutableArray_1_System_Collections_Generic_IListU3CTU3E_get_Item_m2446982ED9E06819F65568242EEB91F5ED09D9FD_AdjustorThunk(Il2CppObject *, int, const MethodInfo *)} ...}}	const MethodInfo * *
	▶ nestedTypes	0x0000000000000000 {???}	Il2CppClass * *
	▶ implementedInterfaces	0x0000018dd9b0ab90 {0x0000018dd9b0ac08 {image=0x0000018cf9030eb0 {name=0x0000018cf954d0c5 "mscorlib.dll" ...} ...}}	Il2CppClass * *
	▶ interfaceOffsets	0x0000018dd9b11588 {interfaceType=0x0000018dd9b0ac08 {image=0x0000018cf9030eb0 {name=0x0000018cf954d0c5 "mscorlib.dll" ...} ...} ...}	Il2CppRuntimeInterfaceOffsetPair *
	static_fields	0x0000018dd9553740	void *
	▶ rgctx_data	0x0000018dd9b11980 {rgctxDataDummy=0x0000018dd9b114d0 method=0x0000018dd9b114d0 {methodPointer=0x00007fffae247b40 {GameAssembly.dll!ImmutableArray_1_ThrowInvalidOperationIfNotInitialized_mB210BDB576FC9F46AC8DE88100B19F274D472D4E_AdjustorThunk(Il2CppObject *, const MethodInfo *)} ...} ...}	const Il2CppRGCTXData *
	▶ typeHierarchy	0x0000018dd9b11570 {0x0000018cf9205910 {image=0x0000018cf9030eb0 {name=0x0000018cf954d0c5 "mscorlib.dll" ...} ...}}	Il2CppClass * *
	unity_user_data	0x0000000000000000	void *
	initializationExceptionGCHandle	0	unsigned int
	cctor_started	0	unsigned int
	cctor_finished	0	unsigned int
	cctor_thread	0	unsigned __int64
	genericContainerHandle	0x0000000000000000	const ___Il2CppMetadataGenericContainerHandle *
	instance_size	24	unsigned int
	actualSize	24	unsigned int
	element_size	0	unsigned int
	native_size	-1	int
	static_fields_size	8	unsigned int
	thread_static_fields_size	0	unsigned int
	thread_static_fields_offset	-1	int
	flags	1048841	unsigned int
	token	33554465	unsigned int
	method_count	68	unsigned short
	property_count	17	unsigned short
	field_count	2	unsigned short
	event_count	0	unsigned short
	nested_type_count	0	unsigned short
	vtable_count	41	unsigned short
	interfaces_count	13	unsigned short
	interface_offsets_count	13	unsigned short
	typeHierarchyDepth	3 '\x3'	unsigned char
	genericRecursionDepth	1 '\x1'	unsigned char
	rank	0 '\0'	unsigned char
	minimumAlignment	8 '\b'	unsigned char
	naturalAligment	8 '\b'	unsigned char
	packingSize	0 '\0'	unsigned char
	initialized_and_no_error	1 '\x1'	unsigned char
	valuetype	1 '\x1'	unsigned char
	initialized	1 '\x1'	unsigned char
	enumtype	0 '\0'	unsigned char
	is_generic	0 '\0'	unsigned char
	has_references	1 '\x1'	unsigned char
	init_pending	0 '\0'	unsigned char
	size_inited	1 '\x1'	unsigned char
	has_finalize	0 '\0'	unsigned char
	has_cctor	1 '\x1'	unsigned char
	is_blittable	0 '\0'	unsigned char
	is_import_or_windows_runtime	0 '\0'	unsigned char
	is_vtable_initialized	1 '\x1'	unsigned char
	has_initialization_error	0 '\0'	unsigned char
	vtable	0x0000018dd9b08448 {...}	VirtualInvokeData[0]

[kamyker]

Good news: https://forum.unity.com/threads/il2cpp-crash-at-malloc.1144004/#post-7344806

[liiir1985]

nice to hear that Unity already addressed the issue.
Any news about this?

[kamyker]

It was supposed to get fixed in 2020.3.16 but it still crashes.

[kamyker]

Seems like it was caused by another plugin that probably corrupted memory later on used by ilruntime.