mjit.c: fix deadlock on class serial increment

This is reported by @hasimo. Fixing a case like this:

 #0  __lll_lock_wait () at ../sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:135
 #1  0x00007fc7bd824dbd in __GI___pthread_mutex_lock (mutex=mutex@entry=0x55946d294440 <mjit_engine_mutex>) at ../nptl/pthread_mutex_lock.c:80               4
 #2  0x000055946cec54d9 in rb_native_mutex_lock (lock=lock@entry=0x55946d294440 <mjit_engine_mutex>) at thread_pthread.c:211
 #3  0x000055946cde10ca in CRITICAL_SECTION_START (msg=0x55946cfb5423 "mjit_gc_start_hook", level=4) at mjit.c:392
 #4  mjit_gc_start_hook () at mjit.c:412
 #5  0x000055946cda0dfe in gc_enter (event=0x55946cfaf91e "gc_rest", objspace=0x55946da51760) at gc.c:6623
 #6  gc_rest (objspace=objspace@entry=0x55946da51760) at gc.c:6515
 #7  0x000055946cd9f1cf in gc_rest (objspace=0x55946da51760) at gc.c:7841
 #8  objspace_malloc_increase (objspace=objspace@entry=0x55946da51760, new_size=<optimized out>, old_size=old_size@entry=0, type=type@entry=MEMOP_TYPE_MALLOC, mem=0x7fc7a4439010) at gc.c:7842
 #9  0x000055946cda1706 in objspace_malloc_fixup (size=<optimized out>, mem=0x7fc7a4439010, objspace=0x55946da51760) at gc.c:7910
 #10 objspace_xmalloc0 (objspace=0x55946da51760, size=<optimized out>, size@entry=3145728) at gc.c:7939
 #11 0x000055946cda3620 in ruby_xmalloc0 (size=3145728) at gc.c:8006
 #12 ruby_xmalloc (size=size@entry=3145728) at gc.c:8015
 #13 0x000055946ce93f4c in st_init_table_with_size (type=0x55946d28da30 <objhash>, size=<optimized out>) at st.c:602
 #14 0x000055946ce94287 in rebuild_table (tab=tab@entry=0x55946db669f0) at st.c:777
 #15 0x000055946ce963f7 in rebuild_table_if_necessary (tab=0x55946db669f0) at st.c:1139
 #16 st_add_direct_with_hash (hash=8577035585096733536, value=20, key=808451, tab=0x55946db669f0) at st.c:1207
 #17 st_update (tab=0x55946db669f0, key=key@entry=808451, func=<optimized out>, arg=140726472841392) at st.c:1512
 #18 0x000055946cda9e27 in tbl_update (optional_arg=<optimized out>, func=<optimized out>, key=<optimized out>, hash=<optimized out>) at hash.c:561
 #19 rb_hash_aset (hash=94095983218480, key=key@entry=808451, val=val@entry=20) at hash.c:1654
 #20 0x000055946cde243a in mjit_add_class_serial (class_serial=class_serial@entry=404225) at mjit.c:1414                    3
 #21 0x000055946cefcfab in rb_next_class_serial () at vm.c:321
 #22 0x000055946cf48324 in class_alloc (klass=<optimized out>, flags=28) at class.c:178
 #23 rb_include_class_new (module=module@entry=94096115733840, super=0) at class.c:820
 #24 0x000055946cf487ac in include_modules_at (klass=klass@entry=94096135960920, c=<optimized out>, module=<optimized out>, module@entry=94096115734160, search_super=search_super@entry=1) at class.c:913
 #25 0x000055946cf48ac8 in rb_include_module (klass=94096135960920, module=module@entry=94096115734160) at class.c:870
 #26 0x000055946cd84993 in rb_mod_append_features (module=94096115734160, include=<optimized out>) at eval.c:1178
 #27 0x000055946cf06829 in vm_call0_cfunc_with_frame (ci=0x7ffd6f6c9a20, cc=0x7ffd6f6c9ba0, argv=0x7ffd6f6c9ba0, calling=0x7ffd6f6c9a30, ec=0x55946da519c8) at vm_eval.c:87
 #28 vm_call0_cfunc (argv=0x7ffd6f6c9ba0, cc=0x7ffd6f6c9ba0, ci=0x7ffd6f6c9a20, calling=0x7ffd6f6c9a30, ec=0x55946da519c8) at vm_eval.c:102
 #29 vm_call0_body (ec=ec@entry=0x55946da519c8, calling=calling@entry=0x7ffd6f6c9ae0, ci=ci@entry=0x7ffd6f6c9ad0, cc=cc@entry=0x7ffd6f6c9b00, argv=argv@entry=0x7ffd6f6c9ba0) at vm_eval.c:133
 #30 0x000055946cf074b2 in vm_call0 (me=<optimized out>, argv=0x7ffd6f6c9ba0, argc=1, id=4849, recv=94096115734160, ec=0x55946da519c8) at vm_eval.c:60
 #31 rb_call0 (ec=0x55946da519c8, recv=94096115734160, mid=4849, mid@entry=94096135960920, argc=argc@entry=1, argv=argv@entry=0x7ffd6f6c9ba0, scope=scope@entry=CALL_FCALL, self=94096135960920) at vm_eval.c:302
 #32 0x000055946cf07b9b in rb_call (scope=CALL_FCALL, argv=0x7ffd6f6c9ba0, argc=1, mid=94096135960920, recv=<optimized out>) at vm_eval.c:595
 #33 rb_funcallv (recv=<optimized out>, mid=mid@entry=4849, argc=argc@entry=1, argv=argv@entry=0x7ffd6f6c9ba0) at vm_eval.c:825
 #34 0x000055946cd848a7 in rb_mod_include (argc=0, argv=0x7fc7bdb4fce8, module=94096135960920) at eval.c:1203
 #35 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x5594710c06b0, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4df00, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #36 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4df00, calling=<optimized out>, ci=0x5594710c06b0, cc=<optimized out>) at vm_insnhelper.c:1944
 #37 0x000055946cf0b5c2 in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:779
 #38 0x000055946cf02f4c in vm_exec (ec=ec@entry=0x55946da519c8) at vm.c:1804
 #39 0x000055946cf035fc in invoke_block (captured=0x7ffd6f6ca0a0, opt_pc=<optimized out>, type=<optimized out>, cref=0x559476c23930, self=94096135960920, iseq=0x559471335ee0, ec=0x55946da519c8) at vm.c:1005
 #40 invoke_iseq_block_from_c (ec=0x55946da519c8, captured=0x7ffd6f6ca0a0, self=94096135960920, argc=<optimized out>, argv=<optimized out>, passed_block_handler=0, cref=0x559476c23930, is_lambda=0) at vm.c:1057
 #41 0x000055946cf04520 in invoke_block_from_c_bh (ec=ec@entry=0x55946da519c8, block_handler=<optimized out>, argc=argc@entry=1, argv=argv@entry=0x7ffd6f6ca108, cref=<optimized out>, is_lambda=<optimized out>, is_lambda@entry=0, force_blockarg=0, passed_block_handler=0) at vm.c:1075
 #42 0x000055946cf04958 in vm_yield_with_cref (is_lambda=0, cref=<optimized out>, argv=0x7ffd6f6ca108, argc=1, ec=0x55946da519c8) at vm.c:1112
 #43 yield_under (under=94096135960920, self=<optimized out>, argc=argc@entry=1, argv=argv@entry=0x7ffd6f6ca108) at vm_eval.c:1572
 #44 0x000055946cf04b12 in rb_mod_module_exec (argc=argc@entry=1, argv=argv@entry=0x7ffd6f6ca108, mod=<optimized out>) at vm_eval.c:1770
 #45 0x000055946ce00fc6 in rb_mod_initialize (module=94096135960920) at object.c:1978
 #46 0x000055946cf06829 in vm_call0_cfunc_with_frame (ci=0x7ffd6f6ca130, cc=0x7fc7bdb4fc98, argv=0x7fc7bdb4fc98, calling=0x7ffd6f6ca140, ec=0x55946da519c8) at vm_eval.c:87
 #47 vm_call0_cfunc (argv=0x7fc7bdb4fc98, cc=0x7fc7bdb4fc98, ci=0x7ffd6f6ca130, calling=0x7ffd6f6ca140, ec=0x55946da519c8) at vm_eval.c:102
 #48 vm_call0_body (ec=ec@entry=0x55946da519c8, calling=calling@entry=0x7ffd6f6ca1f0, ci=ci@entry=0x7ffd6f6ca1e0, cc=cc@entry=0x7ffd6f6ca210, argv=argv@entry=0x7fc7bdb4fc98) at vm_eval.c:133
 #49 0x000055946cf074b2 in vm_call0 (me=<optimized out>, argv=0x7fc7bdb4fc98, argc=0, id=3057, recv=94096135960920, ec=0x55946da519c8) at vm_eval.c:60
 #50 rb_call0 (ec=0x55946da519c8, recv=recv@entry=94096135960920, mid=mid@entry=3057, argc=argc@entry=3057, argv=argv@entry=0x0, scope=scope@entry=CALL_FCALL, self=94095983466120) at vm_eval.c:302
 #51 0x000055946cf07b9b in rb_call (scope=CALL_FCALL, argv=0x0, argc=3057, mid=3057, recv=94096135960920) at vm_eval.c:595
 #52 rb_funcallv (recv=recv@entry=94096135960920, mid=mid@entry=3057, argc=argc@entry=0, argv=argv@entry=0x7fc7bdb4fc98) at vm_eval.c:825
 #53 0x000055946cd89673 in rb_obj_call_init (obj=obj@entry=94096135960920, argc=argc@entry=0, argv=argv@entry=0x7fc7bdb4fc98) at eval.c:1590
 #54 0x000055946ce048a1 in rb_class_s_new (argc=0, argv=0x7fc7bdb4fc98, klass=<optimized out>) at object.c:2153
 #55 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x559471339c80, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4dfa8, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #56 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4dfa8, calling=<optimized out>, ci=0x559471339c80, cc=<optimized out>) at vm_insnhelper.c:1944
 #57 0x000055946cf0cb05 in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:716
 #58 0x000055946cf02f4c in vm_exec (ec=ec@entry=0x55946da519c8) at vm.c:1804
 #59 0x000055946cf03274 in invoke_bmethod (ec=ec@entry=0x55946da519c8, iseq=iseq@entry=0x55946f15cbc0, self=self@entry=94096115734640, me=me@entry=0x559475664e28, type=type@entry=572653825, opt_pc=0, captured=0x55947158e8a0) at vm.c:1026
 #60 0x000055946cf03534 in invoke_iseq_block_from_c (ec=0x55946da519c8, captured=0x55947158e8a0, self=94096115734640, argc=<optimized out>, argv=<optimized out>, passed_block_handler=0, cref=0x0, is_lambda=1) at vm.c:1060
 #61 0x000055946cf036ce in invoke_block_from_c_proc (ec=<optimized out>, proc=<optimized out>, self=<optimized out>, argc=1, argv=<optimized out>, passed_block_handler=<optimized out>, is_lambda=<optimized out>) at vm.c:1150
 #62 0x000055946cf03811 in vm_invoke_bmethod (block_handler=<optimized out>, argv=<optimized out>, argc=1, self=<optimized out>, proc=<optimized out>, ec=0x55946da519c8) at vm.c:1175
 #63 vm_call_bmethod_body (ci=<optimized out>, cc=0x55946f625960, argv=<optimized out>, calling=0x7ffd6f6ca9b0, ec=0x55946da519c8) at vm_insnhelper.c:1971
 #64 vm_call_bmethod (ec=0x55946da519c8, cfp=0x7fc7bdc4e0c0, calling=0x7ffd6f6ca9b0, ci=<optimized out>, cc=0x55946f625960) at vm_insnhelper.c:1988
 #65 0x000055946cf03ea3 in vm_call_method (ec=0x55946da519c8, cfp=0x7fc7bdc4e0c0, calling=<optimized out>, ci=<optimized out>, cc=<optimized out>) at vm_insnhelper.c:2417
 #66 0x000055946cf0e63e in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:797
 #67 0x000055946cf02f4c in vm_exec (ec=ec@entry=0x55946da519c8) at vm.c:1804
 #68 0x000055946cf06767 in vm_call0_body (ec=ec@entry=0x55946da519c8, calling=calling@entry=0x7ffd6f6cad00, ci=ci@entry=0x7ffd6f6cacf0, cc=cc@entry=0x7ffd6f6cad20, argv=argv@entry=0x7ffd6f6cadb0) at vm_eval.c:129
 #69 0x000055946cf074b2 in vm_call0 (me=<optimized out>, argv=0x7ffd6f6cadb0, argc=1, id=3681, recv=94096115734640, ec=0x55946da519c8) at vm_eval.c:60
 #70 rb_call0 (ec=0x55946da519c8, recv=recv@entry=94096115734640, mid=3681, argc=argc@entry=1, argv=argv@entry=0x7ffd6f6cad90, scope=scope@entry=CALL_FCALL, self=94095983452880) at vm_eval.c:302
 #71 0x000055946cf07b9b in rb_call (scope=CALL_FCALL, argv=0x7ffd6f6cad90, argc=1, mid=<optimized out>, recv=94096115734640) at vm_eval.c:595
 #72 rb_funcallv (recv=recv@entry=94096115734640, mid=<optimized out>, argc=argc@entry=1, argv=argv@entry=0x7ffd6f6cadb0) at vm_eval.c:825
 #73 0x000055946cf477d2 in rb_class_inherited (super=super@entry=94096115734640, klass=klass@entry=94096135961440) at class.c:625
 #74 0x000055946cf0f796 in vm_declare_class (super=<optimized out>, cbase=94096094868200, flags=<optimized out>, id=847387) at vm_insnhelper.c:3134
 #75 vm_define_class (super=<optimized out>, cbase=<optimized out>, flags=<optimized out>, id=847387) at vm_insnhelper.c:3167
 #76 vm_find_or_create_class_by_id (super=<optimized out>, cbase=<optimized out>, flags=<optimized out>, id=847387) at vm_insnhelper.c:3196
 #77 vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:685
 #78 0x000055946cf02f4c in vm_exec (ec=0x55946da519c8) at vm.c:1804
 #79 0x000055946cf118d1 in rb_iseq_eval (iseq=iseq@entry=0x559471f1b548) at vm.c:2046
 #80 0x000055946cdd2164 in rb_load_internal0 (ec=ec@entry=0x55946da519c8, fname=fname@entry=94096135872160, wrap=wrap@entry=0) at load.c:611
 #81 0x000055946cdd41f1 in rb_require_internal (fname=94096135872400, fname@entry=94096135872440, safe=0) at load.c:992
 #82 0x000055946cdd4493 in rb_require_safe (safe=<optimized out>, fname=94096135872440) at load.c:1038
 #83 rb_f_require (obj=<optimized out>, fname=94096135872440) at load.c:820
 #84 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x5594708700a0, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4e168, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #85 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4e168, calling=<optimized out>, ci=0x5594708700a0, cc=<optimized out>) at vm_insnhelper.c:1944
 #86 0x000055946cf03ea3 in vm_call_method (ec=0x55946da519c8, cfp=0x7fc7bdc4e168, calling=<optimized out>, ci=<optimized out>, cc=<optimized out>) at vm_insnhelper.c:2417
 #87 0x000055946cf0e63e in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:797
 #88 0x000055946cf02f4c in vm_exec (ec=ec@entry=0x55946da519c8) at vm.c:1804
 #89 0x000055946cf035fc in invoke_block (captured=0x7fc7bdc4e490, opt_pc=<optimized out>, type=<optimized out>, cref=0x0, self=94096096426480, iseq=0x55946e49f0b8, ec=0x55946da519c8) at vm.c:1005
 #90 invoke_iseq_block_from_c (ec=0x55946da519c8, captured=0x7fc7bdc4e490, self=94096096426480, argc=<optimized out>, argv=<optimized out>, passed_block_handler=0, cref=0x0, is_lambda=0) at vm.c:1057
 #91 0x000055946cf04699 in invoke_block_from_c_bh (argc=<optimized out>, passed_block_handler=<optimized out>, cref=<optimized out>, is_lambda=<optimized out>, force_blockarg=<optimized out>, argv=<optimized out>, block_handler=<optimized out>, ec=<optimized out>) at vm.c:1075
 #92 vm_yield (argc=1, argv=0x7ffd6f6cb938, ec=<optimized out>) at vm.c:1120
 #93 rb_yield_0 (argv=0x7ffd6f6cb938, argc=1) at vm_eval.c:980
 #94 rb_yield_1 (val=94096130169040) at vm_eval.c:986
 #95 rb_yield (val=<optimized out>) at vm_eval.c:996
 #96 0x000055946cf2113d in rb_ary_each (ary=94096076222560) at array.c:1820
 #97 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x55946ed0d090, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4e478, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #98 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4e478, calling=<optimized out>, ci=0x55946ed0d090, cc=<optimized out>) at vm_insnhelper.c:1944
 #99 0x000055946cf0cb05 in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:716
 #100 0x000055946cf02f4c in vm_exec (ec=ec@entry=0x55946da519c8) at vm.c:1804
 #101 0x000055946cf035fc in invoke_block (captured=0x7fc7bdc4e500, opt_pc=<optimized out>, type=<optimized out>, cref=0x0, self=94096096426480, iseq=0x55946e49f298, ec=0x55946da519c8) at vm.c:1005
 #102 invoke_iseq_block_from_c (ec=0x55946da519c8, captured=0x7fc7bdc4e500, self=94096096426480, argc=<optimized out>, argv=<optimized out>, passed_block_handler=0, cref=0x0, is_lambda=0) at vm.c:1057
 #103 0x000055946cf04699 in invoke_block_from_c_bh (argc=<optimized out>, passed_block_handler=<optimized out>, cref=<optimized out>, is_lambda=<optimized out>, force_blockarg=<optimized out>, argv=<optimized out>, block_handler=<optimized out>, ec=<optimized out>) at vm.c:1075
 #104 vm_yield (argc=1, argv=0x7ffd6f6cbdf8, ec=<optimized out>) at vm.c:1120
 #105 rb_yield_0 (argv=0x7ffd6f6cbdf8, argc=1) at vm_eval.c:980
 #106 rb_yield_1 (val=94096095502480) at vm_eval.c:986
 #107 rb_yield (val=<optimized out>) at vm_eval.c:996
 #108 0x000055946cf2113d in rb_ary_each (ary=94096095328480) at array.c:1820
 #109 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x55946e8552a0, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4e4e8, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #110 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4e4e8, calling=<optimized out>, ci=0x55946e8552a0, cc=<optimized out>) at vm_insnhelper.c:1944
 #111 0x000055946cf0cb05 in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:716
 #112 0x000055946cf02f4c in vm_exec (ec=ec@entry=0x55946da519c8) at vm.c:1804
 #113 0x000055946cf06767 in vm_call0_body (ec=ec@entry=0x55946da519c8, calling=calling@entry=0x7ffd6f6cc2d0, ci=ci@entry=0x7ffd6f6cc2c0, cc=cc@entry=0x7ffd6f6cc2f0, argv=argv@entry=0x7ffd6f6cc390) at vm_eval.c:129
 #114 0x000055946cf074b2 in vm_call0 (me=<optimized out>, argv=0x7ffd6f6cc390, argc=0, id=135807, recv=94096096186440, ec=0x55946da519c8) at vm_eval.c:60
 #115 rb_call0 (ec=0x55946da519c8, recv=94096096186440, mid=135807, argc=<optimized out>, argv=argv@entry=0x8, scope=scope@entry=CALL_PUBLIC, self=94095993048320) at vm_eval.c:302
 #116 0x000055946cf0a31a in rb_call (scope=CALL_PUBLIC, argv=0x8, argc=<optimized out>, mid=<optimized out>, recv=<optimized out>) at vm_eval.c:595
 #117 rb_funcall_with_block (recv=<optimized out>, mid=<optimized out>, argc=argc@entry=0, argv=argv@entry=0x7ffd6f6cc390, passed_procval=passed_procval@entry=8) at vm_eval.c:857
 #118 0x000055946ceb319c in rb_sym_proc_call (mid=<optimized out>, argc=argc@entry=1, argv=argv@entry=0x7ffd6f6cc388, passed_proc=passed_proc@entry=8) at string.c:10480
 #119 0x000055946cf0477c in vm_yield_with_symbol (block_handler=0, argv=0x7ffd6f6cc388, argc=1, symbol=<optimized out>, ec=<optimized out>) at vm_insnhelper.c:2573
 #120 invoke_block_from_c_bh (argc=<optimized out>, passed_block_handler=<optimized out>, cref=<optimized out>, is_lambda=<optimized out>, force_blockarg=<optimized out>, argv=<optimized out>, block_handler=<optimized out>, ec=<optimized out>) at vm.c:1084
 #121 vm_yield (argc=1, argv=0x7ffd6f6cc388, ec=<optimized out>) at vm.c:1120
 #122 rb_yield_0 (argv=0x7ffd6f6cc388, argc=1) at vm_eval.c:980
 #123 rb_yield_1 (val=94096096186440) at vm_eval.c:986
 #124 rb_yield (val=<optimized out>) at vm_eval.c:996
 #125 0x000055946cf2113d in rb_ary_each (ary=94095993048320) at array.c:1820
 #126 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x5594744d8280, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4e590, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #127 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4e590, calling=<optimized out>, ci=0x5594744d8280, cc=<optimized out>) at vm_insnhelper.c:1944
 #128 0x000055946cf03ea3 in vm_call_method (ec=0x55946da519c8, cfp=0x7fc7bdc4e590, calling=<optimized out>, ci=<optimized out>, cc=<optimized out>) at vm_insnhelper.c:2417
 #129 0x000055946cf0cb05 in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:716
 #130 0x000055946cf02f4c in vm_exec (ec=ec@entry=0x55946da519c8) at vm.c:1804
 #131 0x000055946cf035fc in invoke_block (captured=0x7ffd6f6cc8e0, opt_pc=<optimized out>, type=<optimized out>, cref=0x559474604128, self=94096096426480, iseq=0x5594745027e8, ec=0x55946da519c8) at vm.c:1005
 #132 invoke_iseq_block_from_c (ec=0x55946da519c8, captured=0x7ffd6f6cc8e0, self=94096096426480, argc=<optimized out>, argv=<optimized out>, passed_block_handler=0, cref=0x559474604128, is_lambda=0) at vm.c:1057
 #133 0x000055946cf04520 in invoke_block_from_c_bh (ec=ec@entry=0x55946da519c8, block_handler=<optimized out>, argc=argc@entry=1, argv=argv@entry=0x7fc7bdb4f7f8, cref=<optimized out>, is_lambda=<optimized out>, is_lambda@entry=0, force_blockarg=0, passed_block_handler=0) at vm.c:1075
 #134 0x000055946cf04958 in vm_yield_with_cref (is_lambda=0, cref=<optimized out>, argv=0x7fc7bdb4f7f8, argc=1, ec=0x55946da519c8) at vm.c:1112
 #135 yield_under (under=94096093646040, self=<optimized out>, argc=1, argv=0x7fc7bdb4f7f8) at vm_eval.c:1572
 #136 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x55946e5cd230, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4e600, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #137 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4e600, calling=<optimized out>, ci=0x55946e5cd230, cc=<optimized out>) at vm_insnhelper.c:1944
 #138 0x000055946cf0cb05 in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:716
 #139 0x000055946cf02f4c in vm_exec (ec=ec@entry=0x55946da519c8) at vm.c:1804
 #140 0x000055946cf035fc in invoke_block (captured=0x5594744c4fb0, opt_pc=<optimized out>, type=<optimized out>, cref=0x0, self=94095990659320, iseq=0x55946e192aa0, ec=0x55946da519c8) at vm.c:1005
 #141 invoke_iseq_block_from_c (ec=0x55946da519c8, captured=0x5594744c4fb0, self=94095990659320, argc=<optimized out>, argv=<optimized out>, passed_block_handler=0, cref=0x0, is_lambda=0) at vm.c:1057
 #142 0x000055946cf04699 in invoke_block_from_c_bh (argc=<optimized out>, passed_block_handler=<optimized out>, cref=<optimized out>, is_lambda=<optimized out>, force_blockarg=<optimized out>, argv=<optimized out>, block_handler=<optimized out>, ec=<optimized out>) at vm.c:1075
 #143 vm_yield (argc=1, argv=0x7ffd6f6ccdc8, ec=<optimized out>) at vm.c:1120
 #144 rb_yield_0 (argv=0x7ffd6f6ccdc8, argc=1) at vm_eval.c:980
 #145 rb_yield_1 (val=94096094867920) at vm_eval.c:986
 #146 rb_yield (val=<optimized out>) at vm_eval.c:996
 #147 0x000055946cf2113d in rb_ary_each (ary=94096094867160) at array.c:1820
 #148 0x000055946cf06829 in vm_call0_cfunc_with_frame (ci=0x7ffd6f6cce00, cc=0x7ffd6f6cce70, argv=0x7fc7bdb4f6b8, calling=0x7ffd6f6cce50, ec=0x55946da519c8) at vm_eval.c:87
 #149 vm_call0_cfunc (argv=0x7fc7bdb4f6b8, cc=0x7ffd6f6cce70, ci=0x7ffd6f6cce00, calling=0x7ffd6f6cce50, ec=0x55946da519c8) at vm_eval.c:102
 #150 vm_call0_body (ec=0x55946da519c8, calling=calling@entry=0x7ffd6f6ccec0, ci=ci@entry=0x7ffd6f6cceb0, cc=cc@entry=0x7ffd6f6ccee0, argv=0x7fc7bdb4f6b8) at vm_eval.c:133
 #151 0x000055946cf06c50 in vm_call0 (me=<optimized out>, argv=<optimized out>, argc=<optimized out>, id=<optimized out>, recv=<optimized out>, ec=<optimized out>) at vm_eval.c:60
 #152 rb_vm_call (ec=<optimized out>, recv=<optimized out>, id=<optimized out>, argc=<optimized out>, argv=<optimized out>, me=<optimized out>) at vm_eval.c:209
 #153 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x55946dba2780, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4e7c0, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #154 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4e7c0, calling=<optimized out>, ci=0x55946dba2780, cc=<optimized out>) at vm_insnhelper.c:1944
 #155 0x000055946cf03ea3 in vm_call_method (ec=0x55946da519c8, cfp=0x7fc7bdc4e7c0, calling=<optimized out>, ci=<optimized out>, cc=<optimized out>) at vm_insnhelper.c:2417
 #156 0x000055946cf0cb05 in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:716
 #157 0x000055946cf02f4c in vm_exec (ec=0x55946da519c8) at vm.c:1804
 #158 0x000055946cf118d1 in rb_iseq_eval (iseq=iseq@entry=0x55946dfed3a8) at vm.c:2046
 #159 0x000055946cdd2164 in rb_load_internal0 (ec=ec@entry=0x55946da519c8, fname=fname@entry=94095988939080, wrap=wrap@entry=0) at load.c:611
 #160 0x000055946cdd41f1 in rb_require_internal (fname=94095988939160, fname@entry=94095988939200, safe=0) at load.c:992
 #161 0x000055946cdd4493 in rb_require_safe (safe=<optimized out>, fname=94095988939200) at load.c:1038
 #162 rb_f_require (obj=<optimized out>, fname=94095988939200) at load.c:820
 #163 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x55946dffa920, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4e948, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #164 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4e948, calling=<optimized out>, ci=0x55946dffa920, cc=<optimized out>) at vm_insnhelper.c:1944
 #165 0x000055946cf03ea3 in vm_call_method (ec=0x55946da519c8, cfp=0x7fc7bdc4e948, calling=<optimized out>, ci=<optimized out>, cc=<optimized out>) at vm_insnhelper.c:2417
 #166 0x000055946cf0b5c2 in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:779
 #167 0x000055946cf02f4c in vm_exec (ec=0x55946da519c8) at vm.c:1804
 #168 0x000055946cf118d1 in rb_iseq_eval (iseq=iseq@entry=0x55946dfee438) at vm.c:2046
 #169 0x000055946cdd2164 in rb_load_internal0 (ec=ec@entry=0x55946da519c8, fname=fname@entry=94095993039280, wrap=wrap@entry=0) at load.c:611
 #170 0x000055946cdd41f1 in rb_require_internal (fname=fname@entry=94095993043840, safe=0) at load.c:992
 #171 0x000055946cdd4493 in rb_require_safe (safe=<optimized out>, fname=94095993043840) at load.c:1038
 #172 rb_f_require (obj=<optimized out>, fname=94095993043840) at load.c:820
 #173 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x55946ea12160, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4e9b8, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #174 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4e9b8, calling=<optimized out>, ci=0x55946ea12160, cc=<optimized out>) at vm_insnhelper.c:1944
 #175 0x000055946cf03ea3 in vm_call_method (ec=0x55946da519c8, cfp=0x7fc7bdc4e9b8, calling=<optimized out>, ci=<optimized out>, cc=<optimized out>) at vm_insnhelper.c:2417
 #176 0x000055946cf0b5c2 in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:779
 #177 0x000055946cf02f4c in vm_exec (ec=0x55946da519c8) at vm.c:1804
 #178 0x000055946cf118d1 in rb_iseq_eval (iseq=iseq@entry=0x55946e3d7c48) at vm.c:2046
 #179 0x000055946cdd2164 in rb_load_internal0 (ec=ec@entry=0x55946da519c8, fname=fname@entry=94095988920840, wrap=<optimized out>) at load.c:611
 #180 0x000055946cdd2850 in rb_load_internal (wrap=0, fname=94095988920840) at load.c:642
 #181 rb_f_load (argc=<optimized out>, argv=<optimized out>) at load.c:710
 #182 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x55946e7c96e0, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4ea28, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #183 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4ea28, calling=<optimized out>, ci=0x55946e7c96e0, cc=<optimized out>) at vm_insnhelper.c:1944
 #184 0x000055946cf03ea3 in vm_call_method (ec=0x55946da519c8, cfp=0x7fc7bdc4ea28, calling=<optimized out>, ci=<optimized out>, cc=<optimized out>) at vm_insnhelper.c:2417
 #185 0x000055946cf0b5c2 in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:779
 #186 0x000055946cf02f4c in vm_exec (ec=ec@entry=0x55946da519c8) at vm.c:1804
 #187 0x000055946cf035fc in invoke_block (captured=0x7fc7bdc4eae8, opt_pc=<optimized out>, type=<optimized out>, cref=0x0, self=94095998891400, iseq=0x55946e4dae10, ec=0x55946da519c8) at vm.c:1005
 #188 invoke_iseq_block_from_c (ec=0x55946da519c8, captured=0x7fc7bdc4eae8, self=94095998891400, argc=<optimized out>, argv=<optimized out>, passed_block_handler=0, cref=0x0, is_lambda=0) at vm.c:1057
 #189 0x000055946cf04699 in invoke_block_from_c_bh (argc=<optimized out>, passed_block_handler=<optimized out>, cref=<optimized out>, is_lambda=<optimized out>, force_blockarg=<optimized out>, argv=<optimized out>, block_handler=<optimized out>, ec=<optimized out>) at vm.c:1075
 #190 vm_yield (argc=1, argv=0x7ffd6f6ce8e8, ec=<optimized out>) at vm.c:1120
 #191 rb_yield_0 (argv=0x7ffd6f6ce8e8, argc=1) at vm_eval.c:980
 #192 rb_yield_1 (val=94095988924840) at vm_eval.c:986
 #193 rb_yield (val=<optimized out>) at vm_eval.c:996
 #194 0x000055946cf2113d in rb_ary_each (ary=94095988920960) at array.c:1820
 #195 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x55946e421000, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4ead0, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #196 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4ead0, calling=<optimized out>, ci=0x55946e421000, cc=<optimized out>) at vm_insnhelper.c:1944
 #197 0x000055946cf03ea3 in vm_call_method (ec=0x55946da519c8, cfp=0x7fc7bdc4ead0, calling=<optimized out>, ci=<optimized out>, cc=<optimized out>) at vm_insnhelper.c:2417
 #198 0x000055946cf0cb05 in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:716
 #199 0x000055946cf02f4c in vm_exec (ec=0x55946da519c8) at vm.c:1804
 #200 0x000055946cf118d1 in rb_iseq_eval (iseq=iseq@entry=0x55946e35f2c0) at vm.c:2046
 #201 0x000055946cdd2164 in rb_load_internal0 (ec=ec@entry=0x55946da519c8, fname=fname@entry=94095992643280, wrap=<optimized out>) at load.c:611
 #202 0x000055946cdd2850 in rb_load_internal (wrap=0, fname=94095992643280) at load.c:642
 #203 rb_f_load (argc=<optimized out>, argv=<optimized out>) at load.c:710
 #204 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x55946e24bb20, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4ec58, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #205 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4ec58, calling=<optimized out>, ci=0x55946e24bb20, cc=<optimized out>) at vm_insnhelper.c:1944
 #206 0x000055946cf03ea3 in vm_call_method (ec=0x55946da519c8, cfp=0x7fc7bdc4ec58, calling=<optimized out>, ci=<optimized out>, cc=<optimized out>) at vm_insnhelper.c:2417
 #207 0x000055946cf0b5c2 in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:779
 #208 0x000055946cf02f4c in vm_exec (ec=0x55946da519c8) at vm.c:1804
 #209 0x000055946cf118d1 in rb_iseq_eval (iseq=iseq@entry=0x55946e3a7390) at vm.c:2046
 #210 0x000055946cdd2164 in rb_load_internal0 (ec=ec@entry=0x55946da519c8, fname=fname@entry=94095993616120, wrap=<optimized out>) at load.c:611
 #211 0x000055946cdd2850 in rb_load_internal (wrap=0, fname=94095993616120) at load.c:642
 #212 rb_f_load (argc=<optimized out>, argv=<optimized out>) at load.c:710
 #213 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x55946e6a00d0, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4ecc8, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #214 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4ecc8, calling=<optimized out>, ci=0x55946e6a00d0, cc=<optimized out>) at vm_insnhelper.c:1944
 #215 0x000055946cf03ea3 in vm_call_method (ec=0x55946da519c8, cfp=0x7fc7bdc4ecc8, calling=<optimized out>, ci=<optimized out>, cc=<optimized out>) at vm_insnhelper.c:2417
 #216 0x000055946cf0b5c2 in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:779
 #217 0x000055946cf02f4c in vm_exec (ec=0x55946da519c8) at vm.c:1804
 #218 0x000055946cf118d1 in rb_iseq_eval (iseq=iseq@entry=0x55946e470100) at vm.c:2046
 #219 0x000055946cdd2164 in rb_load_internal0 (ec=ec@entry=0x55946da519c8, fname=fname@entry=94095993672200, wrap=<optimized out>) at load.c:611
 #220 0x000055946cdd2850 in rb_load_internal (wrap=0, fname=94095993672200) at load.c:642
 #221 rb_f_load (argc=<optimized out>, argv=<optimized out>) at load.c:710
 #222 0x000055946cefb61f in vm_call_cfunc_with_frame (ci=0x55946e3306a0, cc=<optimized out>, calling=<optimized out>, reg_cfp=0x7fc7bdc4efa0, ec=0x55946da519c8) at vm_insnhelper.c:1928
 #223 vm_call_cfunc (ec=0x55946da519c8, reg_cfp=0x7fc7bdc4efa0, calling=<optimized out>, ci=0x55946e3306a0, cc=<optimized out>) at vm_insnhelper.c:1944
 #224 0x000055946cf03ea3 in vm_call_method (ec=0x55946da519c8, cfp=0x7fc7bdc4efa0, calling=<optimized out>, ci=<optimized out>, cc=<optimized out>) at vm_insnhelper.c:2417
 #225 0x000055946cf0b5c2 in vm_exec_core (ec=ec@entry=0x55946da519c8, initial=initial@entry=0) at /tmp/ruby-build.20180216151216.13740/ruby-trunk/insns.def:779
 #226 0x000055946cf02f4c in vm_exec (ec=0x55946da519c8) at vm.c:1804
 #227 0x000055946cf119d5 in rb_iseq_eval_main (iseq=iseq@entry=0x55946e4bbba0) at vm.c:2057
 #228 0x000055946cd83d54 in ruby_exec_internal (n=0x55946e4bbba0) at eval.c:247
 #229 0x000055946cd87fdf in ruby_exec_node (n=0x55946e4bbba0) at eval.c:311
 #230 ruby_run_node (n=<optimized out>) at eval.c:303
 #231 0x000055946cd831bf in main (argc=22, argv=0x7ffd6f6d0148) at ./main.c:42

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62433 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 2 insertions, 2 deletions

diff --git a/mjit.c b/mjit.c
index 50254fe671..3ba889bda2 100644
--- a/mjit.c
+++ b/mjit.c
@@ -1410,9 +1410,9 @@ mjit_add_class_serial(rb_serial_t class_serial)
     if (!mjit_init_p)
         return;
 
-    CRITICAL_SECTION_START(3, "in mjit_add_class_serial");
+    /* Do not wrap CRITICAL_SECTION here. This function is only called in main thread
+       and guarded by GVL, and `rb_hash_aset` may cause GC and deadlock in it. */
     rb_hash_aset(valid_class_serials, LONG2FIX(class_serial), Qtrue);
-    CRITICAL_SECTION_FINISH(3, "in mjit_add_class_serial");
 }
 
 /* A hook to update valid_class_serials. This should NOT be used in MJIT worker. */