[ruby-core:104900] [Ruby master Bug#17052] Ruby with LTO enabled has issues with SIGSEGV handler

[v.ondruch@tiscali.cz]

Issue #17052 has been updated by vo.x (Vit Ondruch).

Status changed from Third Party's Issue to Open

Changing state back to open, because this is unresolved and I am repeatedly hitting this issue in various reincarnations. So this is the debug session on PPC64LE:

~~~
$ gdb --args ./miniruby -e'Process.kill("SIGSEGV",$$)'
GNU gdb (GDB) Fedora 10.2-6.fc35
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License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
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There is NO WARRANTY, to the extent permitted by law.
Type "show copying" and "show warranty" for details.
This GDB was configured as "ppc64le-redhat-linux-gnu".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<https://www.gnu.org/software/gdb/bugs/>.
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    <http://www.gnu.org/software/gdb/documentation/>.

For help, type "help".
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Reading symbols from ./miniruby...
warning: File "/builddir/build/BUILD/ruby-3.0.2/.gdbinit" auto-loading has been declined by your `auto-load safe-path' set to "$debugdir:$datadir/auto-load".
To enable execution of this file add
    add-auto-load-safe-path /builddir/build/BUILD/ruby-3.0.2/.gdbinit
line to your configuration file "/builddir/.gdbinit".
To completely disable this security protection add
    set auto-load safe-path /
line to your configuration file "/builddir/.gdbinit".
For more information about this security protection see the
"Auto-loading safe path" section in the GDB manual.  E.g., run from the shell:
    info "(gdb)Auto-loading safe path"
(gdb) r
Starting program: /builddir/build/BUILD/ruby-3.0.2/miniruby -eProcess.kill\(\"SIGSEGV\",\$\$\)
Download failed: No route to host.  Continuing without debug info for /lib64/libz.so.1.
Download failed: No route to host.  Continuing without debug info for /lib64/libgmp.so.10.
Download failed: No route to host.  Continuing without debug info for /lib64/libcrypt.so.2.
Download failed: No route to host.  Continuing without debug info for /lib64/libm.so.6.
Download failed: No route to host.  Continuing without debug info for /lib64/libc.so.6.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff7aa8810 in kill () from /lib64/libc.so.6
Missing separate debuginfos, use: dnf debuginfo-install glibc-2.34-1.fc35.ppc64le gmp-6.2.0-7.fc35.ppc64le libxcrypt-4.4.24-1.fc35.ppc64le zlib-1.2.11-30.fc35.ppc64le
(gdb) c
Continuing.
-e:1: [BUG] Segmentation fault at 0x590fb15c0000001f
ruby 3.0.2p107 (2021-07-07 revision 0db68f0233) [powerpc64le-linux]

-- Control frame information -----------------------------------------------
c:0003 p:---- s:0012 e:000011 CFUNC  :kill
c:0002 p:0015 s:0006 e:000005 EVAL   -e:1 [FINISH]
c:0001 p:0000 s:0003 E:0013f0 (none) [FINISH]

-- Ruby level backtrace information ----------------------------------------
-e:1:in `<main>'
-e:1:in `kill'

-- C level backtrace information -------------------------------------------

Program received signal SIGSEGV, Segmentation fault.
0x000000010031fa44 in uleb128 (p=0x1005986a0) at addr2line.c:200
200     unsigned char b = *(unsigned char *)(*p)++;
(gdb) bt
#0  0x000000010031fa44 in uleb128 (p=0x1005986a0) at addr2line.c:200
#1  di_read_die (reader=0x100598668, die=0x100598588) at addr2line.c:1335
#2  0x0000000100337d4c in read_abstract_origin (line=0x1005985f8, abstract_origin=760312297580551, reader=0x100598668) at addr2line.c:1604
#3  debug_info_read (traces=<optimized out>, offset=<optimized out>, lines=<optimized out>, num_traces=<optimized out>, reader=<optimized out>) at addr2line.c:1668
#4  fill_lines (num_traces=num_traces@entry=19, check_debuglink=check_debuglink@entry=1, objp=0x100599010, objp@entry=0x1005990a0, lines=lines@entry=0x1005e2c50, offset=0, offset@entry=-1, 
    traces=<optimized out>) at addr2line.c:1888
#5  0x0000000100338d1c in rb_dump_backtrace_with_lines.constprop.0 (num_traces=<optimized out>, traces=<optimized out>) at addr2line.c:2287
#6  0x000000010031dfec in rb_print_backtrace () at vm_dump.c:760
#7  0x00000001003356a8 in rb_vm_bugreport.constprop.0 (ctx=<optimized out>) at vm_dump.c:998
#8  0x00000001000cd8c4 in rb_bug_for_fatal_signal (default_sighandler=0x0, sig=<optimized out>, ctx=<optimized out>, fmt=0x100383a98 "Segmentation fault at %p") at error.c:786
#9  0x0000000100256388 in sigsegv (sig=<optimized out>, info=0x10059a330, ctx=0x1005995b0) at signal.c:960
#10 <signal handler called>
#11 0x00007ffff7aa8810 in kill () from /lib64/libc.so.6
#12 0x000000010025ad70 in rb_f_kill (argc=<optimized out>, argv=0x7ffff78e0050) at signal.c:439
#13 0x00000001001fb448 in proc_rb_f_kill (c=<optimized out>, v=<optimized out>, _=<optimized out>) at process.c:8605
#14 0x00000001002e92d8 in ractor_safe_call_cfunc_m1 (recv=<optimized out>, argc=<optimized out>, argv=<optimized out>, func=<optimized out>) at vm_insnhelper.c:2739
#15 0x00000001002f2120 in vm_call_cfunc_with_frame (ec=0x100491ac0, reg_cfp=0x7fffffffe170, calling=<optimized out>) at vm_insnhelper.c:2929
#16 0x00000001002f4f34 in vm_sendish (ec=0x100491ac0, reg_cfp=0x7ffff79dffa0, cd=0x1005c2eb0, block_handler=<optimized out>, method_explorer=<optimized out>) at vm_insnhelper.c:4530
#17 0x00000001002fa2ac in vm_exec_core (ec=0x100491ac0, initial=<optimized out>) at insns.def:789
#18 0x0000000100315200 in rb_vm_exec (ec=0x100491ac0, mjit_enable_p=<optimized out>) at vm.c:2172
#19 0x0000000100317040 in rb_iseq_eval_main (iseq=0x1004a9fb0) at vm.c:2420
#20 0x00000001000d7c8c in rb_ec_exec_node (ec=ec@entry=0x100491ac0, n=n@entry=0x1004a9fb0) at eval.c:317
#21 0x00000001000d7df4 in ruby_run_node (n=0x1004a9fb0) at eval.c:375
#22 0x000000010002afb8 in main (argc=<optimized out>, argv=<optimized out>) at ./main.c:50
(gdb) 
~~~

----------------------------------------
Bug #17052: Ruby with LTO enabled has issues with SIGSEGV handler
https://bugs.ruby-lang.org/issues/17052#change-93260

* Author: vo.x (Vit Ondruch)
* Status: Open
* Priority: Normal
* ruby -v: ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [powerpc64le-linux]
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN
----------------------------------------
Fedora aims to enable link time optimization (LTO) of packages in next release. The specific changes in configuration options are available here [1]. Since that time, I observe following errors [2] at least on {aarch64,ppc64le} (and possibly also other architectures):

~~~
  1) Failure:
TestBugReporter#test_bug_reporter_add [/builddir/build/BUILD/ruby-2.7.1/test/-ext-/bug_reporter/test_bug_reporter.rb:22]:
pid 32395 killed by SIGSEGV (signal 11) (core dumped)
| -:1: [BUG] Segmentation fault at 0x000003e800007e8b
| ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [powerpc64le-linux]
| 
| -- Control frame information -----------------------------------------------
| c:0003 p:---- s:0012 e:000011 CFUNC  :kill
| c:0002 p:0021 s:0006 e:000005 EVAL   -:1 [FINISH]
| c:0001 p:0000 s:0003 E:000f80 (none) [FINISH]
| 
| -- Ruby level backtrace information ----------------------------------------
| -:1:in `<main>'
| -:1:in `kill'
| 
| -- C level backtrace information -------------------------------------------
..
1. [2/2] Assertion for "stderr"
   | Expected /Sample bug reporter: 12345/
   | to match
   |   "-- Control frame information -----------------------------------------------\n"+
   |   "c:0003 p:---- s:0012 e:000011 CFUNC  :kill\n"+
   |   "c:0002 p:0021 s:0006 e:000005 EVAL   -:1 [FINISH]\n"+
   |   "c:0001 p:0000 s:0003 E:000f80 (none) [FINISH]\n\n"+
   |   "-- Ruby level backtrace information ----------------------------------------\n"+
   |   "-:1:in `<main>'\n"+
   |   "-:1:in `kill'\n\n"+
   |   "-- C level backtrace information -------------------------------------------\n"
   | after 4 patterns with 120 characters.
  2) Failure:
TestRubyOptions#test_segv_loaded_features [/builddir/build/BUILD/ruby-2.7.1/test/ruby/test_rubyoptions.rb:735]:
pid 38444 killed by SIGSEGV (signal 11) (core dumped)
| -e:1: [BUG] Segmentation fault at 0x000003e80000962c
| ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [powerpc64le-linux]
| 
| -- Control frame information -----------------------------------------------
| c:0003 p:---- s:0012 e:000011 CFUNC  :kill
| c:0002 p:0016 s:0006 e:000005 BLOCK  -e:1 [FINISH]
| c:0001 p:0000 s:0003 E:002460 (none) [FINISH]
| 
| -- Ruby level backtrace information ----------------------------------------
| -e:1:in `block in <main>'
| -e:1:in `kill'
| 
| -- C level backtrace information -------------------------------------------
..
1. [2/2] Assertion for "stderr"
   | <""> expected but was
   | <"-- C level backtrace information -------------------------------------------\n">.
  3) Failure:
TestRubyOptions#test_segv_setproctitle [/builddir/build/BUILD/ruby-2.7.1/test/ruby/test_rubyoptions.rb:749]:
pid 38451 killed by SIGSEGV (signal 11) (core dumped)
| -e:1: [BUG] Segmentation fault at 0x000003e800009633
| ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [powerpc64le-linux]
| 
| -- Control frame information -----------------------------------------------
| c:0003 p:---- s:0012 e:000011 CFUNC  :kill
| c:0002 p:0029 s:0006 e:000005 EVAL   -e:1 [FINISH]
| c:0001 p:0000 s:0003 E:000480 (none) [FINISH]
| 
| -- Ruby level backtrace information ----------------------------------------
| -e:1:in `<main>'
| -e:1:in `kill'
| 
| -- C level backtrace information -------------------------------------------
..
1. [2/2] Assertion for "stderr"
   | <""> expected but was
   | <"-- C level backtrace information -------------------------------------------\n">.
  4) Failure:
TestRubyOptions#test_segv_test [/builddir/build/BUILD/ruby-2.7.1/test/ruby/test_rubyoptions.rb:729]:
pid 38460 killed by SIGSEGV (signal 11) (core dumped)
| -e:1: [BUG] Segmentation fault at 0x000003e80000963c
| ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [powerpc64le-linux]
| 
| -- Control frame information -----------------------------------------------
| c:0003 p:---- s:0012 e:000011 CFUNC  :kill
| c:0002 p:0015 s:0006 e:000005 EVAL   -e:1 [FINISH]
| c:0001 p:0000 s:0003 E:0006a0 (none) [FINISH]
| 
| -- Ruby level backtrace information ----------------------------------------
| -e:1:in `<main>'
| -e:1:in `kill'
| 
| -- C level backtrace information -------------------------------------------
..
1. [2/2] Assertion for "stderr"
   | <""> expected but was
   | <"-- C level backtrace information -------------------------------------------\n">.
Finished tests in 840.600443s, 25.0047 tests/s, 3238.9681 assertions/s.
21019 tests, 2722678 assertions, 4 failures, 0 errors, 70 skips
ruby -v: ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [powerpc64le-linux]
~~~

When I raised the issue on fedora-devel ML [3], there was suggestion that it might happen when signal handler modifies any global variable. Now I am not sure if that is the case. Can somebody confirm? Or investigate/fix this, please?



[1]: https://src.fedoraproject.org/rpms/redhat-rpm-config/c/5baaf4a99cc77572d3496a7000674098bef7ed68?branch=master
[2]: https://koschei.fedoraproject.org/package/ruby
[3]: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/D6YUXPU5C2RWIQMNHLT4HBYXUGVKKPOW/



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