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Propagate type information (context) across basic blocks #26

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maximecb opened this issue Jan 21, 2021 · 0 comments
Closed

Propagate type information (context) across basic blocks #26

maximecb opened this issue Jan 21, 2021 · 0 comments

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@maximecb
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The first step will be to do a refactoring to allow us to have a list of multiple block versions per basic block. I think that I will use a linked list because it's a good fit here, since each block_t object is already heap allocated.

The second step will be to implement a matching function to look for compatible block versions.

tenderlove added a commit that referenced this issue Apr 20, 2021
This commit adds a check on the ep just like in the mark function.  The
env can contain null bytes if allocation tracing is enabled.

We're seeing errors during autocompaction like this:

```
(lldb) bt 40
* thread #1, name = 'ruby', stop reason = signal SIGABRT
    frame #0: 0x00007f7d64b6018b libc.so.6`raise + 203
    frame #1: 0x00007f7d64b3f859 libc.so.6`abort + 299
    frame #2: 0x000055af5f2fefc9 ruby`die at error.c:764:5
    frame #3: 0x000055af5f2ff1ac ruby`rb_bug_for_fatal_signal(default_sighandler=0x0000000000000000, sig=11, ctx=0x000055af60bc3340, fmt="") at error.c:804:5
    frame #4: 0x000055af5f4bd08f ruby`sigsegv(sig=11, info=0x000055af60bc3470, ctx=0x000055af60bc3340) at signal.c:960:5
    frame #5: 0x00007f7d64ebe3c0 libpthread.so.0`__restore_rt
    frame #6: 0x000055af5f339b0a ruby`gc_ref_update_imemo(objspace=0x000055af60b2b040, obj=0x00007f7d5b513fd0) at gc.c:9046:13
    frame #7: 0x000055af5f339172 ruby`gc_update_object_references(objspace=0x000055af60b2b040, obj=0x00007f7d5b513fd0) at gc.c:9307:9
    frame #8: 0x000055af5f338e79 ruby`gc_ref_update(vstart=0x00007f7d5b510010, vend=0x00007f7d5b513ff8, stride=40, objspace=0x000055af60b2b040, page=0x000055af62577aa0) at gc.c:9452:21
    frame #9: 0x000055af5f337846 ruby`gc_update_references(objspace=0x000055af60b2b040, heap=0x000055af60b2b068) at gc.c:9481:9
    frame #10: 0x000055af5f336569 ruby`gc_compact_finish(objspace=0x000055af60b2b040, heap=0x000055af60b2b068) at gc.c:4840:5
    frame #11: 0x000055af5f335efb ruby`gc_page_sweep(objspace=0x000055af60b2b040, heap=0x000055af60b2b068, sweep_page=0x000055af63a1eb30) at gc.c:5046:13
    frame #12: 0x000055af5f3355c5 ruby`gc_sweep_step(objspace=0x000055af60b2b040, heap=0x000055af60b2b068) at gc.c:5214:19
    frame #13: 0x000055af5f33daf6 ruby`gc_sweep_rest(objspace=0x000055af60b2b040) at gc.c:5271:2
    frame #14: 0x000055af5f33cacd ruby`gc_sweep(objspace=0x000055af60b2b040) at gc.c:5389:2
    frame #15: 0x000055af5f33c21d ruby`gc_marks_rest(objspace=0x000055af60b2b040) at gc.c:7555:5
    frame #16: 0x000055af5f324d41 ruby`gc_rest(objspace=0x000055af60b2b040) at gc.c:8457:13
    frame #17: 0x000055af5f3297d8 ruby`garbage_collect(objspace=0x000055af60b2b040, reason=45568) at gc.c:8318:9
    frame #18: 0x000055af5f344ece ruby`garbage_collect_with_gvl(objspace=0x000055af60b2b040, reason=45568) at gc.c:8632:9
    frame #19: 0x000055af5f344e61 ruby`objspace_malloc_gc_stress(objspace=0x000055af60b2b040) at gc.c:10592:9
    frame #20: 0x000055af5f32ced1 ruby`objspace_xmalloc0(objspace=0x000055af60b2b040, size=64) at gc.c:10767:5
    frame #21: 0x000055af5f32ce11 ruby`ruby_xmalloc0(size=64) at gc.c:10988:12
    frame #22: 0x000055af5f32cdac ruby`ruby_xmalloc_body(size=64) at gc.c:10997:12
    frame #23: 0x000055af5f329415 ruby`ruby_xmalloc(size=64) at gc.c:12942:12
    frame #24: 0x00007f7d611c4fe5 objspace.so`newobj_i(tpval=0x00007f7d5b553770, data=0x000055af639031a0) at object_tracing.c:101:35
    frame #25: 0x000055af5f5b283f ruby`tp_call_trace(tpval=0x00007f7d5b553770, trace_arg=0x00007fff1016d398) at vm_trace.c:1115:2
    frame #26: 0x000055af5f5b50ec ruby`exec_hooks_body(ec=0x000055af60b2b700, list=0x000055af60b2b920, trace_arg=0x00007fff1016d398) at vm_trace.c:304:3
    frame #27: 0x000055af5f5b0f24 ruby`exec_hooks_unprotected(ec=0x000055af60b2b700, list=0x000055af60b2b920, trace_arg=0x00007fff1016d398) at vm_trace.c:333:5
    frame #28: 0x000055af5f5b0da8 ruby`rb_exec_event_hooks(trace_arg=0x00007fff1016d398, hooks=0x000055af60b2b920, pop_p=0) at vm_trace.c:378:13
    frame #29: 0x000055af5f33f8e2 ruby`rb_exec_event_hook_orig(ec=0x000055af60b2b700, hooks=0x000055af60b2b920, flag=1048576, self=0x00007f7d5b5c08c0, id=0, called_id=0, klass=0x0000000000000000, data=0x00007f7d5b513fd0, pop_p=0) at vm_core.h:1989:5
    frame #30: 0x000055af5f334975 ruby`gc_event_hook_body(ec=0x000055af60b2b700, objspace=0x000055af60b2b040, event=1048576, data=0x00007f7d5b513fd0) at gc.c:2083:5
  * frame #31: 0x000055af5f3342df ruby`newobj_slowpath_wb_protected [inlined] newobj_slowpath(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, objspace=0x000055af60b2b040, cr=0x000055af60b2b910, wb_protected=1) at gc.c:2284:9
    frame #32: 0x000055af5f33410f ruby`newobj_slowpath_wb_protected(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, objspace=0x000055af60b2b040, cr=0x000055af60b2b910) at gc.c:2299
    frame #33: 0x000055af5f333de9 ruby`newobj_of0(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, wb_protected=1, cr=0x000055af60b2b910) at gc.c:2338:11
    frame #34: 0x000055af5f3227ae ruby`newobj_of(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, v1=0x000055af657d88a0, v2=0x000055af657d8890, v3=0x0000000000000000, wb_protected=1) at gc.c:2348:17
    frame #35: 0x000055af5f322c5b ruby`rb_imemo_new(type=imemo_env, v1=0x000055af657d88a0, v2=0x000055af657d8890, v3=0x0000000000000000, v0=0x00007f7d5b9d19c8) at gc.c:2434:12
    frame #36: 0x000055af5f5a3925 ruby`vm_env_new(env_ep=0x000055af657d88a0, env_body=0x000055af657d8890, env_size=4, iseq=0x00007f7d5b9d19c8) at vm_core.h:1363:33
    frame #37: 0x000055af5f5a3808 ruby`vm_make_env_each(ec=0x000055af60b2b700, cfp=0x00007f7d6482fc90) at vm.c:801:11
    frame #38: 0x000055af5f5a368d ruby`vm_make_env_each(ec=0x000055af60b2b700, cfp=0x00007f7d6482fc20) at vm.c:752:13
    frame #39: 0x000055af5f5a368d ruby`vm_make_env_each(ec=0x000055af60b2b700, cfp=0x00007f7d6482fbb0) at vm.c:752:13
(lldb) f 31
frame #31: 0x000055af5f3342df ruby`newobj_slowpath_wb_protected [inlined] newobj_slowpath(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, objspace=0x000055af60b2b040, cr=0x000055af60b2b910, wb_protected=1) at gc.c:2284:9
   2281	        }
   2282	        GC_ASSERT(obj != 0);
   2283	        newobj_init(klass, flags, wb_protected, objspace, obj);
-> 2284	        gc_event_hook_prep(objspace, RUBY_INTERNAL_EVENT_NEWOBJ, obj, newobj_fill(obj, 0, 0, 0));
   2285	    }
   2286	    RB_VM_LOCK_LEAVE_CR_LEV(cr, &lev);
   2287
(lldb) p obj
(VALUE) $3 = 0x00007f7d5b513fd0
(lldb) f 6
frame #6: 0x000055af5f339b0a ruby`gc_ref_update_imemo(objspace=0x000055af60b2b040, obj=0x00007f7d5b513fd0) at gc.c:9046:13
   9043	        {
   9044	            rb_env_t *env = (rb_env_t *)obj;
   9045	            TYPED_UPDATE_IF_MOVED(objspace, rb_iseq_t *, env->iseq);
-> 9046	            UPDATE_IF_MOVED(objspace, env->ep[VM_ENV_DATA_INDEX_ENV]);
   9047	            gc_update_values(objspace, (long)env->env_size, (VALUE *)env->env);
   9048	        }
   9049	        break;
(lldb) p obj
(VALUE) $4 = 0x00007f7d5b513fd0
(lldb)
```
peterzhu2118 pushed a commit that referenced this issue Apr 21, 2021
This commit adds a check on the ep just like in the mark function.  The
env can contain null bytes if allocation tracing is enabled.

We're seeing errors during autocompaction like this:

```
(lldb) bt 40
* thread #1, name = 'ruby', stop reason = signal SIGABRT
    frame #0: 0x00007f7d64b6018b libc.so.6`raise + 203
    frame #1: 0x00007f7d64b3f859 libc.so.6`abort + 299
    frame #2: 0x000055af5f2fefc9 ruby`die at error.c:764:5
    frame #3: 0x000055af5f2ff1ac ruby`rb_bug_for_fatal_signal(default_sighandler=0x0000000000000000, sig=11, ctx=0x000055af60bc3340, fmt="") at error.c:804:5
    frame #4: 0x000055af5f4bd08f ruby`sigsegv(sig=11, info=0x000055af60bc3470, ctx=0x000055af60bc3340) at signal.c:960:5
    frame #5: 0x00007f7d64ebe3c0 libpthread.so.0`__restore_rt
    frame #6: 0x000055af5f339b0a ruby`gc_ref_update_imemo(objspace=0x000055af60b2b040, obj=0x00007f7d5b513fd0) at gc.c:9046:13
    frame #7: 0x000055af5f339172 ruby`gc_update_object_references(objspace=0x000055af60b2b040, obj=0x00007f7d5b513fd0) at gc.c:9307:9
    frame #8: 0x000055af5f338e79 ruby`gc_ref_update(vstart=0x00007f7d5b510010, vend=0x00007f7d5b513ff8, stride=40, objspace=0x000055af60b2b040, page=0x000055af62577aa0) at gc.c:9452:21
    frame #9: 0x000055af5f337846 ruby`gc_update_references(objspace=0x000055af60b2b040, heap=0x000055af60b2b068) at gc.c:9481:9
    frame #10: 0x000055af5f336569 ruby`gc_compact_finish(objspace=0x000055af60b2b040, heap=0x000055af60b2b068) at gc.c:4840:5
    frame #11: 0x000055af5f335efb ruby`gc_page_sweep(objspace=0x000055af60b2b040, heap=0x000055af60b2b068, sweep_page=0x000055af63a1eb30) at gc.c:5046:13
    frame #12: 0x000055af5f3355c5 ruby`gc_sweep_step(objspace=0x000055af60b2b040, heap=0x000055af60b2b068) at gc.c:5214:19
    frame #13: 0x000055af5f33daf6 ruby`gc_sweep_rest(objspace=0x000055af60b2b040) at gc.c:5271:2
    frame #14: 0x000055af5f33cacd ruby`gc_sweep(objspace=0x000055af60b2b040) at gc.c:5389:2
    frame #15: 0x000055af5f33c21d ruby`gc_marks_rest(objspace=0x000055af60b2b040) at gc.c:7555:5
    frame #16: 0x000055af5f324d41 ruby`gc_rest(objspace=0x000055af60b2b040) at gc.c:8457:13
    frame #17: 0x000055af5f3297d8 ruby`garbage_collect(objspace=0x000055af60b2b040, reason=45568) at gc.c:8318:9
    frame #18: 0x000055af5f344ece ruby`garbage_collect_with_gvl(objspace=0x000055af60b2b040, reason=45568) at gc.c:8632:9
    frame #19: 0x000055af5f344e61 ruby`objspace_malloc_gc_stress(objspace=0x000055af60b2b040) at gc.c:10592:9
    frame #20: 0x000055af5f32ced1 ruby`objspace_xmalloc0(objspace=0x000055af60b2b040, size=64) at gc.c:10767:5
    frame #21: 0x000055af5f32ce11 ruby`ruby_xmalloc0(size=64) at gc.c:10988:12
    frame #22: 0x000055af5f32cdac ruby`ruby_xmalloc_body(size=64) at gc.c:10997:12
    frame #23: 0x000055af5f329415 ruby`ruby_xmalloc(size=64) at gc.c:12942:12
    frame #24: 0x00007f7d611c4fe5 objspace.so`newobj_i(tpval=0x00007f7d5b553770, data=0x000055af639031a0) at object_tracing.c:101:35
    frame #25: 0x000055af5f5b283f ruby`tp_call_trace(tpval=0x00007f7d5b553770, trace_arg=0x00007fff1016d398) at vm_trace.c:1115:2
    frame #26: 0x000055af5f5b50ec ruby`exec_hooks_body(ec=0x000055af60b2b700, list=0x000055af60b2b920, trace_arg=0x00007fff1016d398) at vm_trace.c:304:3
    frame #27: 0x000055af5f5b0f24 ruby`exec_hooks_unprotected(ec=0x000055af60b2b700, list=0x000055af60b2b920, trace_arg=0x00007fff1016d398) at vm_trace.c:333:5
    frame #28: 0x000055af5f5b0da8 ruby`rb_exec_event_hooks(trace_arg=0x00007fff1016d398, hooks=0x000055af60b2b920, pop_p=0) at vm_trace.c:378:13
    frame #29: 0x000055af5f33f8e2 ruby`rb_exec_event_hook_orig(ec=0x000055af60b2b700, hooks=0x000055af60b2b920, flag=1048576, self=0x00007f7d5b5c08c0, id=0, called_id=0, klass=0x0000000000000000, data=0x00007f7d5b513fd0, pop_p=0) at vm_core.h:1989:5
    frame #30: 0x000055af5f334975 ruby`gc_event_hook_body(ec=0x000055af60b2b700, objspace=0x000055af60b2b040, event=1048576, data=0x00007f7d5b513fd0) at gc.c:2083:5
  * frame #31: 0x000055af5f3342df ruby`newobj_slowpath_wb_protected [inlined] newobj_slowpath(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, objspace=0x000055af60b2b040, cr=0x000055af60b2b910, wb_protected=1) at gc.c:2284:9
    frame #32: 0x000055af5f33410f ruby`newobj_slowpath_wb_protected(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, objspace=0x000055af60b2b040, cr=0x000055af60b2b910) at gc.c:2299
    frame #33: 0x000055af5f333de9 ruby`newobj_of0(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, wb_protected=1, cr=0x000055af60b2b910) at gc.c:2338:11
    frame #34: 0x000055af5f3227ae ruby`newobj_of(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, v1=0x000055af657d88a0, v2=0x000055af657d8890, v3=0x0000000000000000, wb_protected=1) at gc.c:2348:17
    frame #35: 0x000055af5f322c5b ruby`rb_imemo_new(type=imemo_env, v1=0x000055af657d88a0, v2=0x000055af657d8890, v3=0x0000000000000000, v0=0x00007f7d5b9d19c8) at gc.c:2434:12
    frame #36: 0x000055af5f5a3925 ruby`vm_env_new(env_ep=0x000055af657d88a0, env_body=0x000055af657d8890, env_size=4, iseq=0x00007f7d5b9d19c8) at vm_core.h:1363:33
    frame #37: 0x000055af5f5a3808 ruby`vm_make_env_each(ec=0x000055af60b2b700, cfp=0x00007f7d6482fc90) at vm.c:801:11
    frame #38: 0x000055af5f5a368d ruby`vm_make_env_each(ec=0x000055af60b2b700, cfp=0x00007f7d6482fc20) at vm.c:752:13
    frame #39: 0x000055af5f5a368d ruby`vm_make_env_each(ec=0x000055af60b2b700, cfp=0x00007f7d6482fbb0) at vm.c:752:13
(lldb) f 31
frame #31: 0x000055af5f3342df ruby`newobj_slowpath_wb_protected [inlined] newobj_slowpath(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, objspace=0x000055af60b2b040, cr=0x000055af60b2b910, wb_protected=1) at gc.c:2284:9
   2281	        }
   2282	        GC_ASSERT(obj != 0);
   2283	        newobj_init(klass, flags, wb_protected, objspace, obj);
-> 2284	        gc_event_hook_prep(objspace, RUBY_INTERNAL_EVENT_NEWOBJ, obj, newobj_fill(obj, 0, 0, 0));
   2285	    }
   2286	    RB_VM_LOCK_LEAVE_CR_LEV(cr, &lev);
   2287
(lldb) p obj
(VALUE) $3 = 0x00007f7d5b513fd0
(lldb) f 6
frame #6: 0x000055af5f339b0a ruby`gc_ref_update_imemo(objspace=0x000055af60b2b040, obj=0x00007f7d5b513fd0) at gc.c:9046:13
   9043	        {
   9044	            rb_env_t *env = (rb_env_t *)obj;
   9045	            TYPED_UPDATE_IF_MOVED(objspace, rb_iseq_t *, env->iseq);
-> 9046	            UPDATE_IF_MOVED(objspace, env->ep[VM_ENV_DATA_INDEX_ENV]);
   9047	            gc_update_values(objspace, (long)env->env_size, (VALUE *)env->env);
   9048	        }
   9049	        break;
(lldb) p obj
(VALUE) $4 = 0x00007f7d5b513fd0
(lldb)
```
casperisfine pushed a commit that referenced this issue May 19, 2021
This commit adds a check on the ep just like in the mark function.  The
env can contain null bytes if allocation tracing is enabled.

We're seeing errors during autocompaction like this:

```
(lldb) bt 40
* thread #1, name = 'ruby', stop reason = signal SIGABRT
    frame #0: 0x00007f7d64b6018b libc.so.6`raise + 203
    frame #1: 0x00007f7d64b3f859 libc.so.6`abort + 299
    frame #2: 0x000055af5f2fefc9 ruby`die at error.c:764:5
    frame #3: 0x000055af5f2ff1ac ruby`rb_bug_for_fatal_signal(default_sighandler=0x0000000000000000, sig=11, ctx=0x000055af60bc3340, fmt="") at error.c:804:5
    frame #4: 0x000055af5f4bd08f ruby`sigsegv(sig=11, info=0x000055af60bc3470, ctx=0x000055af60bc3340) at signal.c:960:5
    frame #5: 0x00007f7d64ebe3c0 libpthread.so.0`__restore_rt
    frame #6: 0x000055af5f339b0a ruby`gc_ref_update_imemo(objspace=0x000055af60b2b040, obj=0x00007f7d5b513fd0) at gc.c:9046:13
    frame #7: 0x000055af5f339172 ruby`gc_update_object_references(objspace=0x000055af60b2b040, obj=0x00007f7d5b513fd0) at gc.c:9307:9
    frame #8: 0x000055af5f338e79 ruby`gc_ref_update(vstart=0x00007f7d5b510010, vend=0x00007f7d5b513ff8, stride=40, objspace=0x000055af60b2b040, page=0x000055af62577aa0) at gc.c:9452:21
    frame #9: 0x000055af5f337846 ruby`gc_update_references(objspace=0x000055af60b2b040, heap=0x000055af60b2b068) at gc.c:9481:9
    frame #10: 0x000055af5f336569 ruby`gc_compact_finish(objspace=0x000055af60b2b040, heap=0x000055af60b2b068) at gc.c:4840:5
    frame #11: 0x000055af5f335efb ruby`gc_page_sweep(objspace=0x000055af60b2b040, heap=0x000055af60b2b068, sweep_page=0x000055af63a1eb30) at gc.c:5046:13
    frame #12: 0x000055af5f3355c5 ruby`gc_sweep_step(objspace=0x000055af60b2b040, heap=0x000055af60b2b068) at gc.c:5214:19
    frame #13: 0x000055af5f33daf6 ruby`gc_sweep_rest(objspace=0x000055af60b2b040) at gc.c:5271:2
    frame #14: 0x000055af5f33cacd ruby`gc_sweep(objspace=0x000055af60b2b040) at gc.c:5389:2
    frame #15: 0x000055af5f33c21d ruby`gc_marks_rest(objspace=0x000055af60b2b040) at gc.c:7555:5
    frame #16: 0x000055af5f324d41 ruby`gc_rest(objspace=0x000055af60b2b040) at gc.c:8457:13
    frame #17: 0x000055af5f3297d8 ruby`garbage_collect(objspace=0x000055af60b2b040, reason=45568) at gc.c:8318:9
    frame #18: 0x000055af5f344ece ruby`garbage_collect_with_gvl(objspace=0x000055af60b2b040, reason=45568) at gc.c:8632:9
    frame #19: 0x000055af5f344e61 ruby`objspace_malloc_gc_stress(objspace=0x000055af60b2b040) at gc.c:10592:9
    frame #20: 0x000055af5f32ced1 ruby`objspace_xmalloc0(objspace=0x000055af60b2b040, size=64) at gc.c:10767:5
    frame #21: 0x000055af5f32ce11 ruby`ruby_xmalloc0(size=64) at gc.c:10988:12
    frame #22: 0x000055af5f32cdac ruby`ruby_xmalloc_body(size=64) at gc.c:10997:12
    frame #23: 0x000055af5f329415 ruby`ruby_xmalloc(size=64) at gc.c:12942:12
    frame #24: 0x00007f7d611c4fe5 objspace.so`newobj_i(tpval=0x00007f7d5b553770, data=0x000055af639031a0) at object_tracing.c:101:35
    frame #25: 0x000055af5f5b283f ruby`tp_call_trace(tpval=0x00007f7d5b553770, trace_arg=0x00007fff1016d398) at vm_trace.c:1115:2
    frame #26: 0x000055af5f5b50ec ruby`exec_hooks_body(ec=0x000055af60b2b700, list=0x000055af60b2b920, trace_arg=0x00007fff1016d398) at vm_trace.c:304:3
    frame #27: 0x000055af5f5b0f24 ruby`exec_hooks_unprotected(ec=0x000055af60b2b700, list=0x000055af60b2b920, trace_arg=0x00007fff1016d398) at vm_trace.c:333:5
    frame #28: 0x000055af5f5b0da8 ruby`rb_exec_event_hooks(trace_arg=0x00007fff1016d398, hooks=0x000055af60b2b920, pop_p=0) at vm_trace.c:378:13
    frame #29: 0x000055af5f33f8e2 ruby`rb_exec_event_hook_orig(ec=0x000055af60b2b700, hooks=0x000055af60b2b920, flag=1048576, self=0x00007f7d5b5c08c0, id=0, called_id=0, klass=0x0000000000000000, data=0x00007f7d5b513fd0, pop_p=0) at vm_core.h:1989:5
    frame #30: 0x000055af5f334975 ruby`gc_event_hook_body(ec=0x000055af60b2b700, objspace=0x000055af60b2b040, event=1048576, data=0x00007f7d5b513fd0) at gc.c:2083:5
  * frame #31: 0x000055af5f3342df ruby`newobj_slowpath_wb_protected [inlined] newobj_slowpath(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, objspace=0x000055af60b2b040, cr=0x000055af60b2b910, wb_protected=1) at gc.c:2284:9
    frame #32: 0x000055af5f33410f ruby`newobj_slowpath_wb_protected(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, objspace=0x000055af60b2b040, cr=0x000055af60b2b910) at gc.c:2299
    frame #33: 0x000055af5f333de9 ruby`newobj_of0(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, wb_protected=1, cr=0x000055af60b2b910) at gc.c:2338:11
    frame #34: 0x000055af5f3227ae ruby`newobj_of(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, v1=0x000055af657d88a0, v2=0x000055af657d8890, v3=0x0000000000000000, wb_protected=1) at gc.c:2348:17
    frame #35: 0x000055af5f322c5b ruby`rb_imemo_new(type=imemo_env, v1=0x000055af657d88a0, v2=0x000055af657d8890, v3=0x0000000000000000, v0=0x00007f7d5b9d19c8) at gc.c:2434:12
    frame #36: 0x000055af5f5a3925 ruby`vm_env_new(env_ep=0x000055af657d88a0, env_body=0x000055af657d8890, env_size=4, iseq=0x00007f7d5b9d19c8) at vm_core.h:1363:33
    frame #37: 0x000055af5f5a3808 ruby`vm_make_env_each(ec=0x000055af60b2b700, cfp=0x00007f7d6482fc90) at vm.c:801:11
    frame #38: 0x000055af5f5a368d ruby`vm_make_env_each(ec=0x000055af60b2b700, cfp=0x00007f7d6482fc20) at vm.c:752:13
    frame #39: 0x000055af5f5a368d ruby`vm_make_env_each(ec=0x000055af60b2b700, cfp=0x00007f7d6482fbb0) at vm.c:752:13
(lldb) f 31
frame #31: 0x000055af5f3342df ruby`newobj_slowpath_wb_protected [inlined] newobj_slowpath(klass=0x00007f7d5b9d19c8, flags=0x000000000000001a, objspace=0x000055af60b2b040, cr=0x000055af60b2b910, wb_protected=1) at gc.c:2284:9
   2281	        }
   2282	        GC_ASSERT(obj != 0);
   2283	        newobj_init(klass, flags, wb_protected, objspace, obj);
-> 2284	        gc_event_hook_prep(objspace, RUBY_INTERNAL_EVENT_NEWOBJ, obj, newobj_fill(obj, 0, 0, 0));
   2285	    }
   2286	    RB_VM_LOCK_LEAVE_CR_LEV(cr, &lev);
   2287
(lldb) p obj
(VALUE) $3 = 0x00007f7d5b513fd0
(lldb) f 6
frame #6: 0x000055af5f339b0a ruby`gc_ref_update_imemo(objspace=0x000055af60b2b040, obj=0x00007f7d5b513fd0) at gc.c:9046:13
   9043	        {
   9044	            rb_env_t *env = (rb_env_t *)obj;
   9045	            TYPED_UPDATE_IF_MOVED(objspace, rb_iseq_t *, env->iseq);
-> 9046	            UPDATE_IF_MOVED(objspace, env->ep[VM_ENV_DATA_INDEX_ENV]);
   9047	            gc_update_values(objspace, (long)env->env_size, (VALUE *)env->env);
   9048	        }
   9049	        break;
(lldb) p obj
(VALUE) $4 = 0x00007f7d5b513fd0
(lldb)
```
tenderlove pushed a commit that referenced this issue Jun 2, 2021
noahgibbs pushed a commit that referenced this issue Oct 20, 2021
XrXr pushed a commit that referenced this issue Oct 20, 2021
XrXr pushed a commit that referenced this issue Oct 20, 2021
XrXr pushed a commit that referenced this issue Oct 21, 2021
maximecb pushed a commit that referenced this issue Aug 2, 2023
[Bug #19793]

Dummy frames are created at the top level when requiring another file.
While requiring a file, it will try to convert using encodings. Some of
these encodings will not respond to to_str. If method_missing is
redefined on Object, then it will call method_missing and attempt raise
an error. However, the iseq is invalid as it's a dummy frame so it will
write an invalid iseq to the created NoMethodError.

The following script crashes:

```
GC.stress = true

class Object
  public :method_missing
end

File.write("/tmp/empty.rb", "")
require "/tmp/empty.rb"
```

With the following backtrace:

```
frame #0: 0x00000001000fa8b8 miniruby`RVALUE_MARKED(obj=4308637824) at gc.c:1638:12
frame #1: 0x00000001000fb440 miniruby`RVALUE_BLACK_P(obj=4308637824) at gc.c:1763:12
frame #2: 0x00000001000facdc miniruby`gc_writebarrier_incremental(a=4308637824, b=4308332208, objspace=0x000000010180b000) at gc.c:8822:9
frame #3: 0x00000001000faad8 miniruby`rb_gc_writebarrier(a=4308637824, b=4308332208) at gc.c:8864:17
frame #4: 0x000000010016aff0 miniruby`rb_obj_written(a=4308637824, oldv=36, b=4308332208, filename="../iseq.c", line=1279) at gc.h:804:9
frame #5: 0x0000000100162a60 miniruby`rb_obj_write(a=4308637824, slot=0x0000000100d09888, b=4308332208, filename="../iseq.c", line=1279) at gc.h:837:5
frame #6: 0x0000000100165b0c miniruby`iseqw_new(iseq=0x0000000100d09880) at iseq.c:1279:9
frame #7: 0x0000000100165a64 miniruby`rb_iseqw_new(iseq=0x0000000100d09880) at iseq.c:1289:12
frame #8: 0x00000001000d8324 miniruby`name_err_init_attr(exc=4309777920, recv=4304780496, method=827660) at error.c:1830:35
frame #9: 0x00000001000d1b80 miniruby`name_err_init(exc=4309777920, mesg=4308332496, recv=4304780496, method=827660) at error.c:1869:12
frame #10: 0x00000001000d1bd4 miniruby`rb_nomethod_err_new(mesg=4308332496, recv=4304780496, method=827660, args=4308332448, priv=0) at error.c:1957:5
frame #11: 0x000000010039049c miniruby`rb_make_no_method_exception(exc=4304914512, format=4308332496, obj=4304780496, argc=1, argv=0x000000016fdfab00, priv=0) at vm_eval.c:959:16
frame #12: 0x00000001003b3274 miniruby`raise_method_missing(ec=0x0000000100b06f40, argc=1, argv=0x000000016fdfab00, obj=4304780496, last_call_status=MISSING_NOENTRY) at vm_eval.c:999:15
frame #13: 0x00000001003945d4 miniruby`rb_method_missing(argc=1, argv=0x000000016fdfab00, obj=4304780496) at vm_eval.c:944:5
...
frame #23: 0x000000010038f5e4 miniruby`rb_vm_call_kw(ec=0x0000000100b06f40, recv=4304780496, id=2865, argc=1, argv=0x000000016fdfab00, me=0x0000000100cbfcf0, kw_splat=0) at vm_eval.c:326:12
frame #24: 0x00000001003c18e4 miniruby`call_method_entry(ec=0x0000000100b06f40, defined_class=4304927952, obj=4304780496, id=2865, cme=0x0000000100cbfcf0, argc=1, argv=0x000000016fdfab00, kw_splat=0) at vm_method.c:2720:20
frame #25: 0x00000001003c440c miniruby`check_funcall_exec(v=6171896792) at vm_eval.c:589:12
frame #26: 0x00000001000dec00 miniruby`rb_vrescue2(b_proc=(miniruby`check_funcall_exec at vm_eval.c:587), data1=6171896792, r_proc=(miniruby`check_funcall_failed at vm_eval.c:596), data2=6171896792, args="Pȗ") at eval.c:919:18
frame #27: 0x00000001000deab0 miniruby`rb_rescue2(b_proc=(miniruby`check_funcall_exec at vm_eval.c:587), data1=6171896792, r_proc=(miniruby`check_funcall_failed at vm_eval.c:596), data2=6171896792) at eval.c:900:17
frame #28: 0x000000010039008c miniruby`check_funcall_missing(ec=0x0000000100b06f40, klass=4304923536, recv=4304780496, mid=3233, argc=0, argv=0x0000000000000000, respond=-1, def=36, kw_splat=0) at vm_eval.c:666:15
frame #29: 0x000000010038fa60 miniruby`rb_check_funcall_default_kw(recv=4304780496, mid=3233, argc=0, argv=0x0000000000000000, def=36, kw_splat=0) at vm_eval.c:703:21
frame #30: 0x000000010038fb04 miniruby`rb_check_funcall(recv=4304780496, mid=3233, argc=0, argv=0x0000000000000000) at vm_eval.c:685:12
frame #31: 0x00000001001c469c miniruby`convert_type_with_id(val=4304780496, tname="String", method=3233, raise=0, index=-1) at object.c:3061:15
frame #32: 0x00000001001c4a4c miniruby`rb_check_convert_type_with_id(val=4304780496, type=5, tname="String", method=3233) at object.c:3153:9
frame #33: 0x00000001002d59f8 miniruby`rb_check_string_type(str=4304780496) at string.c:2571:11
frame #34: 0x000000010014b7b0 miniruby`io_encoding_set(fptr=0x0000000100d09ca0, v1=4304780496, v2=4, opt=4) at io.c:11655:19
frame #35: 0x0000000100139a58 miniruby`rb_io_set_encoding(argc=1, argv=0x000000016fdfb450, io=4308334032) at io.c:13497:5
frame #36: 0x00000001003c0004 miniruby`ractor_safe_call_cfunc_m1(recv=4308334032, argc=1, argv=0x000000016fdfb450, func=(miniruby`rb_io_set_encoding at io.c:13487)) at vm_insnhelper.c:3271:12
...
frame #43: 0x0000000100390b08 miniruby`rb_funcall(recv=4308334032, mid=16593, n=1) at vm_eval.c:1137:12
frame #44: 0x00000001002a43d8 miniruby`load_file_internal(argp_v=6171899936) at ruby.c:2500:5
...
```
casperisfine pushed a commit that referenced this issue Sep 20, 2023
	Fix crash in NoMethodError for dummy frames
	MIME-Version: 1.0
	Content-Type: text/plain; charset=UTF-8
	Content-Transfer-Encoding: 8bit

	[Bug #19793]

	Dummy frames are created at the top level when requiring another file.
	While requiring a file, it will try to convert using encodings. Some of
	these encodings will not respond to to_str. If method_missing is
	redefined on Object, then it will call method_missing and attempt raise
	an error. However, the iseq is invalid as it's a dummy frame so it will
	write an invalid iseq to the created NoMethodError.

	The following script crashes:

	```
	GC.stress = true

	class Object
	  public :method_missing
	end

	File.write("/tmp/empty.rb", "")
	require "/tmp/empty.rb"
	```

	With the following backtrace:

	```
	frame #0: 0x00000001000fa8b8 miniruby`RVALUE_MARKED(obj=4308637824) at gc.c:1638:12
	frame #1: 0x00000001000fb440 miniruby`RVALUE_BLACK_P(obj=4308637824) at gc.c:1763:12
	frame #2: 0x00000001000facdc miniruby`gc_writebarrier_incremental(a=4308637824, b=4308332208, objspace=0x000000010180b000) at gc.c:8822:9
	frame #3: 0x00000001000faad8 miniruby`rb_gc_writebarrier(a=4308637824, b=4308332208) at gc.c:8864:17
	frame #4: 0x000000010016aff0 miniruby`rb_obj_written(a=4308637824, oldv=36, b=4308332208, filename="../iseq.c", line=1279) at gc.h:804:9
	frame #5: 0x0000000100162a60 miniruby`rb_obj_write(a=4308637824, slot=0x0000000100d09888, b=4308332208, filename="../iseq.c", line=1279) at gc.h:837:5
	frame #6: 0x0000000100165b0c miniruby`iseqw_new(iseq=0x0000000100d09880) at iseq.c:1279:9
	frame #7: 0x0000000100165a64 miniruby`rb_iseqw_new(iseq=0x0000000100d09880) at iseq.c:1289:12
	frame #8: 0x00000001000d8324 miniruby`name_err_init_attr(exc=4309777920, recv=4304780496, method=827660) at error.c:1830:35
	frame #9: 0x00000001000d1b80 miniruby`name_err_init(exc=4309777920, mesg=4308332496, recv=4304780496, method=827660) at error.c:1869:12
	frame #10: 0x00000001000d1bd4 miniruby`rb_nomethod_err_new(mesg=4308332496, recv=4304780496, method=827660, args=4308332448, priv=0) at error.c:1957:5
	frame #11: 0x000000010039049c miniruby`rb_make_no_method_exception(exc=4304914512, format=4308332496, obj=4304780496, argc=1, argv=0x000000016fdfab00, priv=0) at vm_eval.c:959:16
	frame #12: 0x00000001003b3274 miniruby`raise_method_missing(ec=0x0000000100b06f40, argc=1, argv=0x000000016fdfab00, obj=4304780496, last_call_status=MISSING_NOENTRY) at vm_eval.c:999:15
	frame #13: 0x00000001003945d4 miniruby`rb_method_missing(argc=1, argv=0x000000016fdfab00, obj=4304780496) at vm_eval.c:944:5
	...
	frame #23: 0x000000010038f5e4 miniruby`rb_vm_call_kw(ec=0x0000000100b06f40, recv=4304780496, id=2865, argc=1, argv=0x000000016fdfab00, me=0x0000000100cbfcf0, kw_splat=0) at vm_eval.c:326:12
	frame #24: 0x00000001003c18e4 miniruby`call_method_entry(ec=0x0000000100b06f40, defined_class=4304927952, obj=4304780496, id=2865, cme=0x0000000100cbfcf0, argc=1, argv=0x000000016fdfab00, kw_splat=0) at vm_method.c:2720:20
	frame #25: 0x00000001003c440c miniruby`check_funcall_exec(v=6171896792) at vm_eval.c:589:12
	frame #26: 0x00000001000dec00 miniruby`rb_vrescue2(b_proc=(miniruby`check_funcall_exec at vm_eval.c:587), data1=6171896792, r_proc=(miniruby`check_funcall_failed at vm_eval.c:596), data2=6171896792, args="Pȗ") at eval.c:919:18
	frame #27: 0x00000001000deab0 miniruby`rb_rescue2(b_proc=(miniruby`check_funcall_exec at vm_eval.c:587), data1=6171896792, r_proc=(miniruby`check_funcall_failed at vm_eval.c:596), data2=6171896792) at eval.c:900:17
	frame #28: 0x000000010039008c miniruby`check_funcall_missing(ec=0x0000000100b06f40, klass=4304923536, recv=4304780496, mid=3233, argc=0, argv=0x0000000000000000, respond=-1, def=36, kw_splat=0) at vm_eval.c:666:15
	frame #29: 0x000000010038fa60 miniruby`rb_check_funcall_default_kw(recv=4304780496, mid=3233, argc=0, argv=0x0000000000000000, def=36, kw_splat=0) at vm_eval.c:703:21
	frame #30: 0x000000010038fb04 miniruby`rb_check_funcall(recv=4304780496, mid=3233, argc=0, argv=0x0000000000000000) at vm_eval.c:685:12
	frame #31: 0x00000001001c469c miniruby`convert_type_with_id(val=4304780496, tname="String", method=3233, raise=0, index=-1) at object.c:3061:15
	frame #32: 0x00000001001c4a4c miniruby`rb_check_convert_type_with_id(val=4304780496, type=5, tname="String", method=3233) at object.c:3153:9
	frame #33: 0x00000001002d59f8 miniruby`rb_check_string_type(str=4304780496) at string.c:2571:11
	frame #34: 0x000000010014b7b0 miniruby`io_encoding_set(fptr=0x0000000100d09ca0, v1=4304780496, v2=4, opt=4) at io.c:11655:19
	frame #35: 0x0000000100139a58 miniruby`rb_io_set_encoding(argc=1, argv=0x000000016fdfb450, io=4308334032) at io.c:13497:5
	frame #36: 0x00000001003c0004 miniruby`ractor_safe_call_cfunc_m1(recv=4308334032, argc=1, argv=0x000000016fdfb450, func=(miniruby`rb_io_set_encoding at io.c:13487)) at vm_insnhelper.c:3271:12
	...
	frame #43: 0x0000000100390b08 miniruby`rb_funcall(recv=4308334032, mid=16593, n=1) at vm_eval.c:1137:12
	frame #44: 0x00000001002a43d8 miniruby`load_file_internal(argp_v=6171899936) at ruby.c:2500:5
	...
	```
	---
	 error.c                   |  4 +++-
	 test/ruby/test_require.rb | 15 +++++++++++++++
	 2 files changed, 18 insertions(+), 1 deletion(-)
st0012 pushed a commit that referenced this issue Nov 30, 2024
[Bug #20921]

When we create a cache entry for a constant, the following sequence of
events could happen:

- vm_track_constant_cache is called to insert a constant cache.
- In vm_track_constant_cache, we first look up the ST table for the ID
  of the constant. Assume the ST table exists because another iseq also
  holds a cache entry for this ID.
- We then insert into this ST table with the iseq_inline_constant_cache.
- However, while inserting into this ST table, it allocates memory, which
  could trigger a GC. Assume that it does trigger a GC.
- The GC frees the one and only other iseq that holds a cache entry for
  this ID.
- In remove_from_constant_cache, it will appear that the ST table is now
  empty because there are no more iseq with cache entries for this ID, so
  we free the ST table.
- We complete GC and continue our st_insert. However, this ST table has
  been freed so we now have a use-after-free.

This issue is very hard to reproduce, because it requires that the GC runs
at a very specific time. However, we can make it show up by applying this
patch which runs GC right before the st_insert to mimic the st_insert
triggering a GC:

    diff --git a/vm_insnhelper.c b/vm_insnhelper.c
    index 3cb23f06f0..a93998136a 100644
    --- a/vm_insnhelper.c
    +++ b/vm_insnhelper.c
    @@ -6338,6 +6338,10 @@ vm_track_constant_cache(ID id, void *ic)
            rb_id_table_insert(const_cache, id, (VALUE)ics);
        }

    +    if (id == rb_intern("MyConstant")) rb_gc();
    +
        st_insert(ics, (st_data_t) ic, (st_data_t) Qtrue);
    }

And if we run this script:

    Object.const_set("MyConstant", "Hello!")

    my_proc = eval("-> { MyConstant }")
    my_proc.call

    my_proc = eval("-> { MyConstant }")
    my_proc.call

We can see that ASAN outputs a use-after-free error:

    ==36540==ERROR: AddressSanitizer: heap-use-after-free on address 0x606000049528 at pc 0x000102f3ceac bp 0x00016d607a70 sp 0x00016d607a68
    READ of size 8 at 0x606000049528 thread T0
        #0 0x102f3cea8 in do_hash st.c:321
        #1 0x102f3ddd0 in rb_st_insert st.c:1132
        #2 0x103140700 in vm_track_constant_cache vm_insnhelper.c:6345
        #3 0x1030b91d8 in vm_ic_track_const_chain vm_insnhelper.c:6356
        #4 0x1030b8cf8 in rb_vm_opt_getconstant_path vm_insnhelper.c:6424
        #5 0x1030bc1e0 in vm_exec_core insns.def:263
        #6 0x1030b55fc in rb_vm_exec vm.c:2585
        #7 0x1030fe0ac in rb_iseq_eval_main vm.c:2851
        #8 0x102a82588 in rb_ec_exec_node eval.c:281
        #9 0x102a81fe0 in ruby_run_node eval.c:319
        #10 0x1027f3db4 in rb_main main.c:43
        #11 0x1027f3bd4 in main main.c:68
        #12 0x183900270  (<unknown module>)

    0x606000049528 is located 8 bytes inside of 56-byte region [0x606000049520,0x606000049558)
    freed by thread T0 here:
        #0 0x104174d40 in free+0x98 (libclang_rt.asan_osx_dynamic.dylib:arm64e+0x54d40)
        #1 0x102ada89c in rb_gc_impl_free default.c:8183
        #2 0x102ada7dc in ruby_sized_xfree gc.c:4507
        #3 0x102ac4d34 in ruby_xfree gc.c:4518
        #4 0x102f3cb34 in rb_st_free_table st.c:663
        #5 0x102bd52d8 in remove_from_constant_cache iseq.c:119
        #6 0x102bbe2cc in iseq_clear_ic_references iseq.c:153
        #7 0x102bbd2a0 in rb_iseq_free iseq.c:166
        #8 0x102b32ed0 in rb_imemo_free imemo.c:564
        #9 0x102ac4b44 in rb_gc_obj_free gc.c:1407
        #10 0x102af4290 in gc_sweep_plane default.c:3546
        #11 0x102af3bdc in gc_sweep_page default.c:3634
        #12 0x102aeb140 in gc_sweep_step default.c:3906
        #13 0x102aeadf0 in gc_sweep_rest default.c:3978
        #14 0x102ae4714 in gc_sweep default.c:4155
        #15 0x102af8474 in gc_start default.c:6484
        #16 0x102afbe30 in garbage_collect default.c:6363
        #17 0x102ad37f0 in rb_gc_impl_start default.c:6816
        #18 0x102ad3634 in rb_gc gc.c:3624
        #19 0x1031406ec in vm_track_constant_cache vm_insnhelper.c:6342
        #20 0x1030b91d8 in vm_ic_track_const_chain vm_insnhelper.c:6356
        #21 0x1030b8cf8 in rb_vm_opt_getconstant_path vm_insnhelper.c:6424
        #22 0x1030bc1e0 in vm_exec_core insns.def:263
        #23 0x1030b55fc in rb_vm_exec vm.c:2585
        #24 0x1030fe0ac in rb_iseq_eval_main vm.c:2851
        #25 0x102a82588 in rb_ec_exec_node eval.c:281
        #26 0x102a81fe0 in ruby_run_node eval.c:319
        #27 0x1027f3db4 in rb_main main.c:43
        #28 0x1027f3bd4 in main main.c:68
        #29 0x183900270  (<unknown module>)

    previously allocated by thread T0 here:
        #0 0x104174c04 in malloc+0x94 (libclang_rt.asan_osx_dynamic.dylib:arm64e+0x54c04)
        #1 0x102ada0ec in rb_gc_impl_malloc default.c:8198
        #2 0x102acee44 in ruby_xmalloc gc.c:4438
        #3 0x102f3c85c in rb_st_init_table_with_size st.c:571
        #4 0x102f3c900 in rb_st_init_table st.c:600
        #5 0x102f3c920 in rb_st_init_numtable st.c:608
        #6 0x103140698 in vm_track_constant_cache vm_insnhelper.c:6337
        #7 0x1030b91d8 in vm_ic_track_const_chain vm_insnhelper.c:6356
        #8 0x1030b8cf8 in rb_vm_opt_getconstant_path vm_insnhelper.c:6424
        #9 0x1030bc1e0 in vm_exec_core insns.def:263
        #10 0x1030b55fc in rb_vm_exec vm.c:2585
        #11 0x1030fe0ac in rb_iseq_eval_main vm.c:2851
        #12 0x102a82588 in rb_ec_exec_node eval.c:281
        #13 0x102a81fe0 in ruby_run_node eval.c:319
        #14 0x1027f3db4 in rb_main main.c:43
        #15 0x1027f3bd4 in main main.c:68
        #16 0x183900270  (<unknown module>)

This commit fixes this bug by adding a inserting_constant_cache_id field
to the VM, which stores the ID that is currently being inserted and, in
remove_from_constant_cache, we don't free the ST table for ID equal to
this one.

Co-Authored-By: Alan Wu <alanwu@ruby-lang.org>
peterzhu2118 added a commit that referenced this issue Dec 3, 2024
[Bug #20921]

When we create a cache entry for a constant, the following sequence of
events could happen:

- vm_track_constant_cache is called to insert a constant cache.
- In vm_track_constant_cache, we first look up the ST table for the ID
  of the constant. Assume the ST table exists because another iseq also
  holds a cache entry for this ID.
- We then insert into this ST table with the iseq_inline_constant_cache.
- However, while inserting into this ST table, it allocates memory, which
  could trigger a GC. Assume that it does trigger a GC.
- The GC frees the one and only other iseq that holds a cache entry for
  this ID.
- In remove_from_constant_cache, it will appear that the ST table is now
  empty because there are no more iseq with cache entries for this ID, so
  we free the ST table.
- We complete GC and continue our st_insert. However, this ST table has
  been freed so we now have a use-after-free.

This issue is very hard to reproduce, because it requires that the GC runs
at a very specific time. However, we can make it show up by applying this
patch which runs GC right before the st_insert to mimic the st_insert
triggering a GC:

    diff --git a/vm_insnhelper.c b/vm_insnhelper.c
    index 3cb23f06f0..a93998136a 100644
    --- a/vm_insnhelper.c
    +++ b/vm_insnhelper.c
    @@ -6338,6 +6338,10 @@ vm_track_constant_cache(ID id, void *ic)
            rb_id_table_insert(const_cache, id, (VALUE)ics);
        }

    +    if (id == rb_intern("MyConstant")) rb_gc();
    +
        st_insert(ics, (st_data_t) ic, (st_data_t) Qtrue);
    }

And if we run this script:

    Object.const_set("MyConstant", "Hello!")

    my_proc = eval("-> { MyConstant }")
    my_proc.call

    my_proc = eval("-> { MyConstant }")
    my_proc.call

We can see that ASAN outputs a use-after-free error:

    ==36540==ERROR: AddressSanitizer: heap-use-after-free on address 0x606000049528 at pc 0x000102f3ceac bp 0x00016d607a70 sp 0x00016d607a68
    READ of size 8 at 0x606000049528 thread T0
        #0 0x102f3cea8 in do_hash st.c:321
        #1 0x102f3ddd0 in rb_st_insert st.c:1132
        #2 0x103140700 in vm_track_constant_cache vm_insnhelper.c:6345
        #3 0x1030b91d8 in vm_ic_track_const_chain vm_insnhelper.c:6356
        #4 0x1030b8cf8 in rb_vm_opt_getconstant_path vm_insnhelper.c:6424
        #5 0x1030bc1e0 in vm_exec_core insns.def:263
        #6 0x1030b55fc in rb_vm_exec vm.c:2585
        #7 0x1030fe0ac in rb_iseq_eval_main vm.c:2851
        #8 0x102a82588 in rb_ec_exec_node eval.c:281
        #9 0x102a81fe0 in ruby_run_node eval.c:319
        #10 0x1027f3db4 in rb_main main.c:43
        #11 0x1027f3bd4 in main main.c:68
        #12 0x183900270  (<unknown module>)

    0x606000049528 is located 8 bytes inside of 56-byte region [0x606000049520,0x606000049558)
    freed by thread T0 here:
        #0 0x104174d40 in free+0x98 (libclang_rt.asan_osx_dynamic.dylib:arm64e+0x54d40)
        #1 0x102ada89c in rb_gc_impl_free default.c:8183
        #2 0x102ada7dc in ruby_sized_xfree gc.c:4507
        #3 0x102ac4d34 in ruby_xfree gc.c:4518
        #4 0x102f3cb34 in rb_st_free_table st.c:663
        #5 0x102bd52d8 in remove_from_constant_cache iseq.c:119
        #6 0x102bbe2cc in iseq_clear_ic_references iseq.c:153
        #7 0x102bbd2a0 in rb_iseq_free iseq.c:166
        #8 0x102b32ed0 in rb_imemo_free imemo.c:564
        #9 0x102ac4b44 in rb_gc_obj_free gc.c:1407
        #10 0x102af4290 in gc_sweep_plane default.c:3546
        #11 0x102af3bdc in gc_sweep_page default.c:3634
        #12 0x102aeb140 in gc_sweep_step default.c:3906
        #13 0x102aeadf0 in gc_sweep_rest default.c:3978
        #14 0x102ae4714 in gc_sweep default.c:4155
        #15 0x102af8474 in gc_start default.c:6484
        #16 0x102afbe30 in garbage_collect default.c:6363
        #17 0x102ad37f0 in rb_gc_impl_start default.c:6816
        #18 0x102ad3634 in rb_gc gc.c:3624
        #19 0x1031406ec in vm_track_constant_cache vm_insnhelper.c:6342
        #20 0x1030b91d8 in vm_ic_track_const_chain vm_insnhelper.c:6356
        #21 0x1030b8cf8 in rb_vm_opt_getconstant_path vm_insnhelper.c:6424
        #22 0x1030bc1e0 in vm_exec_core insns.def:263
        #23 0x1030b55fc in rb_vm_exec vm.c:2585
        #24 0x1030fe0ac in rb_iseq_eval_main vm.c:2851
        #25 0x102a82588 in rb_ec_exec_node eval.c:281
        #26 0x102a81fe0 in ruby_run_node eval.c:319
        #27 0x1027f3db4 in rb_main main.c:43
        #28 0x1027f3bd4 in main main.c:68
        #29 0x183900270  (<unknown module>)

    previously allocated by thread T0 here:
        #0 0x104174c04 in malloc+0x94 (libclang_rt.asan_osx_dynamic.dylib:arm64e+0x54c04)
        #1 0x102ada0ec in rb_gc_impl_malloc default.c:8198
        #2 0x102acee44 in ruby_xmalloc gc.c:4438
        #3 0x102f3c85c in rb_st_init_table_with_size st.c:571
        #4 0x102f3c900 in rb_st_init_table st.c:600
        #5 0x102f3c920 in rb_st_init_numtable st.c:608
        #6 0x103140698 in vm_track_constant_cache vm_insnhelper.c:6337
        #7 0x1030b91d8 in vm_ic_track_const_chain vm_insnhelper.c:6356
        #8 0x1030b8cf8 in rb_vm_opt_getconstant_path vm_insnhelper.c:6424
        #9 0x1030bc1e0 in vm_exec_core insns.def:263
        #10 0x1030b55fc in rb_vm_exec vm.c:2585
        #11 0x1030fe0ac in rb_iseq_eval_main vm.c:2851
        #12 0x102a82588 in rb_ec_exec_node eval.c:281
        #13 0x102a81fe0 in ruby_run_node eval.c:319
        #14 0x1027f3db4 in rb_main main.c:43
        #15 0x1027f3bd4 in main main.c:68
        #16 0x183900270  (<unknown module>)

This commit fixes this bug by adding a inserting_constant_cache_id field
to the VM, which stores the ID that is currently being inserted and, in
remove_from_constant_cache, we don't free the ST table for ID equal to
this one.

Co-Authored-By: Alan Wu <alanwu@ruby-lang.org>
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