From: "vo.x (Vit Ondruch)" <noreply@...>
Date: 2021-12-15T14:03:00+00:00
Subject: [ruby-core:106688] [Ruby master Bug#18133] LTO: TestGCCompact#test_ast_compacts segfaults on i686

Issue #18133 has been updated by vo.x (Vit Ondruch).


Checking on CentOS Steam 9, it is passing on ppc:

https://kojihub.stream.rdu2.redhat.com/koji/taskinfo?taskID=848077

The configure checks:

~~~
checking for mmap... yes
checking for sys/user.h... yes
checking whether PAGE_SIZE is compile-time const... no
~~~

----------------------------------------
Bug #18133: LTO: TestGCCompact#test_ast_compacts segfaults on i686
https://bugs.ruby-lang.org/issues/18133#change-95368

* Author: vo.x (Vit Ondruch)
* Status: Assigned
* Priority: Normal
* ruby -v: ruby 3.0.2p107 (2021-07-07 revision 0db68f0233) [i386-linux]
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
I observe following segfault running the test suite on i686 on RHEL9:

~~~
$ gdb --args ./miniruby -I./lib -I. -I.ext/common  ./tool/runruby.rb --extout=.ext  -- --disable-gems ./test/runner.rb --excludes-dir=./test/excludes -v

... snip ...

(gdb) handle SIGPIPE noprint nostop pass
Signal        Stop	Print	Pass to program	Description
SIGPIPE       No	No	Yes		Broken pipe
(gdb) r

... snip ...

[ 8347/20497] TestGBK#test_mbc_enc_len = 0.00 s
[ 8348/20497] TestGBK#test_mbc_to_code = 0.00 s
[ 8349/20497] TestGCCompact#test_ast_compacts--Type <RET> for more, q to quit, c to continue without paging--

Thread 1 "ruby" received signal SIGSEGV, Segmentation fault.
0xf7e33fe6 in rb_class_remove_from_super_subclasses (klass=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/class.c:96
96		    RCLASS_EXT(entry->next->klass)->parent_subclasses = RCLASS_EXT(klass)->parent_subclasses;
(gdb) bt
#0  0xf7e33fe6 in rb_class_remove_from_super_subclasses (klass=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/class.c:96
#1  obj_free (obj=<optimized out>, objspace=0x5655ac30) at /builddir/build/BUILD/ruby-3.0.2/gc.c:3019
#2  gc_page_sweep (sweep_page=0x5a40e1f0, heap=0x5655ac48, objspace=0x5655ac30) at /builddir/build/BUILD/ruby-3.0.2/gc.c:4914
#3  gc_sweep_step.isra.0 (objspace=<optimized out>, heap=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/gc.c:5134
#4  0xf7ca3f09 in gc_sweep_rest (objspace=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/gc.c:5190
#5  gc_sweep (objspace=0x5655ac30) at /builddir/build/BUILD/ruby-3.0.2/gc.c:5313
#6  0xf7ca8250 in gc_marks (full_mark=<optimized out>, objspace=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/gc.c:7504
#7  gc_start (objspace=<optimized out>, reason=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/gc.c:8322
#8  0xf7ca8530 in garbage_collect (objspace=objspace@entry=0x5655ac30, reason=reason@entry=238592) at /builddir/build/BUILD/ruby-3.0.2/gc.c:8210
#9  0xf7caa723 in gc_start_internal (compact=2, immediate_sweep=2, immediate_mark=2, full_mark=2, self=1448715280, ec=0x5655afac) at /builddir/build/BUILD/ruby-3.0.2/gc.c:8553
#10 gc_compact (ec=0x5655afac, self=1448715280) at /builddir/build/BUILD/ruby-3.0.2/gc.c:9468
#11 0xf7dfae3c in invoke_bf (argv=0x0, bf=<optimized out>, reg_cfp=<optimized out>, ec=0x5655afac) at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:5583
#12 vm_invoke_builtin_delegate (ec=0x5655afac, cfp=<optimized out>, bf=<optimized out>, start_index=0) at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:5607
#13 0xf7e0664c in vm_exec_core (ec=0x0, initial=1448732852) at /builddir/build/BUILD/ruby-3.0.2/insns.def:1482
#14 0xf7e1d0d5 in rb_vm_exec (ec=<optimized out>, mjit_enable_p=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/vm.c:2172
#15 0xf7e0c3c9 in invoke_block (captured=<optimized out>, captured=<optimized out>, opt_pc=<optimized out>, type=<optimized out>, cref=0x0, self=1450588460, iseq=0x5669174c, ec=0x5655afac)
    at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:399
#16 invoke_iseq_block_from_c (me=0x0, is_lambda=<optimized out>, cref=0x0, passed_block_handler=0, kw_splat=0, argv=0xffffbf00, argc=1, self=1450588460, captured=<optimized out>, ec=0x5655afac)
    at /builddir/build/BUILD/ruby-3.0.2/vm.c:1335
#17 invoke_block_from_c_bh (force_blockarg=<optimized out>, is_lambda=<optimized out>, cref=<optimized out>, passed_block_handler=<optimized out>, kw_splat=<optimized out>, argv=<optimized out>, 
    argc=<optimized out>, block_handler=<optimized out>, ec=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/vm.c:1353
#18 vm_yield (kw_splat=0, argv=0xffffbf00, argc=1, ec=0x5655afac) at /builddir/build/BUILD/ruby-3.0.2/vm.c:1398
#19 rb_yield_0 (argv=0xffffbf00, argc=1) at /builddir/build/BUILD/ruby-3.0.2/vm_eval.c:1333
#20 rb_yield (val=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/vm_eval.c:1349
#21 0xf7c2ae74 in rb_ary_collect (ary=1503666180) at /builddir/build/BUILD/ruby-3.0.2/array.c:3635
#22 0xf7dfc835 in vm_call_cfunc_with_frame (ec=0x5655afac, reg_cfp=0xf77f6d70, calling=0xffffc004) at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:2929
#23 0xf7dfdd31 in vm_sendish (ec=0x5655afac, reg_cfp=0xf77f6d70, cd=0x566c8f00, block_handler=4152323453, method_explorer=mexp_search_method) at /builddir/build/BUILD/ruby-3.0.2/vm_callinfo.h:336
#24 0xf7e0590a in vm_exec_core (ec=0x0, initial=1448732852) at /builddir/build/BUILD/ruby-3.0.2/insns.def:770
#25 0xf7e1d0d5 in rb_vm_exec (ec=<optimized out>, mjit_enable_p=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/vm.c:2172
#26 0xf7e0c3c9 in invoke_block (captured=<optimized out>, captured=<optimized out>, opt_pc=<optimized out>, type=<optimized out>, cref=0x0, self=1450588460, iseq=0x56691850, ec=0x5655afac)
    at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:399
#27 invoke_iseq_block_from_c (me=0x0, is_lambda=<optimized out>, cref=0x0, passed_block_handler=0, kw_splat=0, argv=0xffffc2b0, argc=1, self=1450588460, captured=<optimized out>, ec=0x5655afac)
    at /builddir/build/BUILD/ruby-3.0.2/vm.c:1335
#28 invoke_block_from_c_bh (force_blockarg=<optimized out>, is_lambda=<optimized out>, cref=<optimized out>, passed_block_handler=<optimized out>, kw_splat=<optimized out>, argv=<optimized out>, 
    argc=<optimized out>, block_handler=<optimized out>, ec=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/vm.c:1353
#29 vm_yield (kw_splat=0, argv=0xffffc2b0, argc=1, ec=0x5655afac) at /builddir/build/BUILD/ruby-3.0.2/vm.c:1398
#30 rb_yield_0 (argv=0xffffc2b0, argc=1) at /builddir/build/BUILD/ruby-3.0.2/vm_eval.c:1333
#31 rb_yield (val=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/vm_eval.c:1349
#32 0xf7c2ac4a in rb_ary_each (ary=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/array.c:2523
#33 rb_ary_each (ary=1501058480) at /builddir/build/BUILD/ruby-3.0.2/array.c:2517
#34 0xf7dfc835 in vm_call_cfunc_with_frame (ec=0x5655afac, reg_cfp=0xf77f6dfc, calling=0xffffc474) at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:2929
#35 0xf7e00602 in vm_call_method_each_type (ec=0x5655afac, cfp=0xf77f6dfc, calling=0xffffc474) at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:3419
#36 0xf7e00a46 in vm_call_refined (calling=<optimized out>, cfp=0xf77f6dfc, ec=0x5655afac) at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:3398
#37 vm_call_method_each_type (ec=0x5655afac, cfp=0xf77f6dfc, calling=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:3476
#38 0xf7dfdd31 in vm_sendish (ec=0x5655afac, reg_cfp=0xf77f6dfc, cd=0x5669f510, block_handler=4152323593, method_explorer=mexp_search_method) at /builddir/build/BUILD/ruby-3.0.2/vm_callinfo.h:336
#39 0xf7e0590a in vm_exec_core (ec=0x0, initial=1448732852) at /builddir/build/BUILD/ruby-3.0.2/insns.def:770
#40 0xf7e1d0d5 in rb_vm_exec (ec=<optimized out>, mjit_enable_p=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/vm.c:2172
#41 0xf7e0c3c9 in invoke_block (captured=<optimized out>, captured=<optimized out>, opt_pc=<optimized out>, type=<optimized out>, cref=0x0, self=1450588460, iseq=0x566900cc, ec=0x5655afac)
    at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:399
#42 invoke_iseq_block_from_c (me=0x0, is_lambda=<optimized out>, cref=0x0, passed_block_handler=0, kw_splat=0, argv=0xffffc720, argc=1, self=1450588460, captured=<optimized out>, ec=0x5655afac)
    at /builddir/build/BUILD/ruby-3.0.2/vm.c:1335
#43 invoke_block_from_c_bh (force_blockarg=<optimized out>, is_lambda=<optimized out>, cref=<optimized out>, passed_block_handler=<optimized out>, kw_splat=<optimized out>, argv=<optimized out>, 
    argc=<optimized out>, block_handler=<optimized out>, ec=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/vm.c:1353
#44 vm_yield (kw_splat=0, argv=0xffffc720, argc=1, ec=0x5655afac) at /builddir/build/BUILD/ruby-3.0.2/vm.c:1398
#45 rb_yield_0 (argv=0xffffc720, argc=1) at /builddir/build/BUILD/ruby-3.0.2/vm_eval.c:1333
#46 rb_yield (val=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/vm_eval.c:1349
#47 0xf7c2ac4a in rb_ary_each (ary=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/array.c:2523
--Type <RET> for more, q to quit, c to continue without paging--
#48 rb_ary_each (ary=1501058920) at /builddir/build/BUILD/ruby-3.0.2/array.c:2517
#49 0xf7dfc835 in vm_call_cfunc_with_frame (ec=0x5655afac, reg_cfp=0xf77f6ec0, calling=0xffffc8e4) at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:2929
#50 0xf7e00602 in vm_call_method_each_type (ec=0x5655afac, cfp=0xf77f6ec0, calling=0xffffc8e4) at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:3419
#51 0xf7e00a46 in vm_call_refined (calling=<optimized out>, cfp=0xf77f6ec0, ec=0x5655afac) at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:3398
#52 vm_call_method_each_type (ec=0x5655afac, cfp=0xf77f6ec0, calling=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:3476
#53 0xf7dfdd31 in vm_sendish (ec=0x5655afac, reg_cfp=0xf77f6ec0, cd=0x566cbca0, block_handler=4152323789, method_explorer=mexp_search_method) at /builddir/build/BUILD/ruby-3.0.2/vm_callinfo.h:336
#54 0xf7e0590a in vm_exec_core (ec=0x0, initial=1448732852) at /builddir/build/BUILD/ruby-3.0.2/insns.def:770
#55 0xf7e1d0d5 in rb_vm_exec (ec=<optimized out>, mjit_enable_p=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/vm.c:2172
#56 0xf7e1da4e in rb_iseq_eval (iseq=0x5657ad18) at /builddir/build/BUILD/ruby-3.0.2/vm.c:2409
#57 0xf7cdb23e in load_iseq_eval (ec=0x5655afac, fname=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/load.c:594
#58 0xf7ce0ef8 in require_internal (ec=<optimized out>, fname=<optimized out>, exception=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/load.c:1065
#59 0xf7ce10ce in rb_require_string (fname=1448587920) at /builddir/build/BUILD/ruby-3.0.2/load.c:1142
#60 0xf7ce117c in rb_f_require_relative (obj=1448845900, fname=1448588380) at /builddir/build/BUILD/ruby-3.0.2/load.c:857
#61 0xf7dfc835 in vm_call_cfunc_with_frame (ec=0x5655afac, reg_cfp=0xf77f6fd8, calling=0xffffce04) at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:2929
#62 0xf7e00602 in vm_call_method_each_type (ec=0x5655afac, cfp=0xf77f6fd8, calling=0xffffce04) at /builddir/build/BUILD/ruby-3.0.2/vm_insnhelper.c:3419
#63 0xf7dfdd31 in vm_sendish (ec=0x5655afac, reg_cfp=0xf77f6fd8, cd=0x56616828, block_handler=0, method_explorer=mexp_search_method) at /builddir/build/BUILD/ruby-3.0.2/vm_callinfo.h:336
#64 0xf7e04d92 in vm_exec_core (ec=0x0, initial=1448732852) at /builddir/build/BUILD/ruby-3.0.2/insns.def:789
#65 0xf7e1d0d5 in rb_vm_exec (ec=<optimized out>, mjit_enable_p=<optimized out>) at /builddir/build/BUILD/ruby-3.0.2/vm.c:2172
#66 0xf7e1db19 in rb_iseq_eval_main (iseq=0x5657b63c) at /builddir/build/BUILD/ruby-3.0.2/vm.c:2420
#67 0xf7c91b99 in rb_ec_exec_node (ec=ec@entry=0x5655afac, n=n@entry=0x5657b63c) at /builddir/build/BUILD/ruby-3.0.2/eval.c:317
#68 0xf7c964fa in ruby_run_node (n=0x5657b63c) at /builddir/build/BUILD/ruby-3.0.2/eval.c:375
#69 0x56556143 in main (argc=<optimized out>, argv=<optimized out>) at ./main.c:50
~~~

Unfortunately:

1) I don' have better reproducer then to run the whole test suite and even then it is not triggered always. I was not successful to hit the issue running just the single test case or the test file.
2) I have failed to reproduce this on CentOS Stream 9, which is surprising.

Luckily, I can reproduce it on my system.

This is seems to be related to LTO, because I have never faced such issue with LTO disabled.

---Files--------------------------------
mmap.patch (9.45 KB)


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