[Mono]: test_0_ldvirtftn_generic_method in generics.cs crash in Full AOT + Interp mode.

[lateralusX]

Description

Running one of the old Mono runtime regressions tests, generics.cs under Full AOT + Interp crash in test_0_ldvirtftn_generic_method with the following callstack:

interp_init_delegate(_MonoDelegate * del, MonoDelegateTrampInfo * * out_info, _MonoErrorInternal * error) Line 1795    C
mini_init_delegate(_MonoDelegateHandle delegate, _MonoObjectHandle target, void * addr, _MonoMethod * method, _MonoErrorInternal * error) Line 3968    C
mono_delegate_ctor(_MonoObjectHandle this_obj, _MonoObjectHandle target, void * addr, _MonoMethod * method, _MonoErrorInternal * error) Line 7659    C
ves_icall_mono_delegate_ctor(_MonoObject * this_obj_raw, _MonoObject * target_raw, void * addr) Line 1527    C
mono_aot_corlibjit_code_start()    Unknown
generics_Tests_ldvirtftn_T_REF()    Unknown
generics_Tests_test_0_ldvirtftn_generic_method()    Unknown
mono_aot_corlibjit_code_start()    Unknown

Happens because address is pointing into out static_rgctx_trampolines, but there is no method for the delegate, that will trigger fallback into interp_init_delegate that in turn assumes that method_ptr is an interpreter method, https://github.com/dotnet/runtime/blob/main/src/mono/mono/mini/interp/interp.c#L1749, but since this is not an interpreter method, it will trigger the crash in above callstack.

One potential fix is to do a more precise condition in https://github.com/dotnet/runtime/blob/main/src/mono/mono/mini/mini-runtime.c#L4031 like:

if (mono_use_interpreter && !mono_aot_only)

That will make sure not to go through mini_get_interp_callbacks ()->init_delegate when we run in Full AOT + Interp mode, the condition could potentially be made a little more precise to handle this specific case where we already have a working delegate method_ptr in the AOT image (we should favor anything in the AOT image before fallback to interpreter), but maybe we would need to hit init_delegate in some other scenarios running Full AOT + Interp.

Reproduction Steps

Run generics.cs runtime test using Mono Full AOT + Interp mode, https://github.com/dotnet/runtime/blob/main/src/mono/mono/mini/generics.cs

I have only tested it on Windows x64, but will most likely repro on other platforms.

There have also been reports of a similar crash when using Delegate.CreateDelegate under Full AOT + Interp.

Expected behavior

No crash.

Actual behavior

Crash.

Regression?

No response

Known Workarounds

No response

Configuration

No response

Other information

No response