Ruby

Meanwhile it can not be a bad idea for us to avoid SEGV even when DWARF is broken.

Thank you for the investigation. There is a whole thread on Fedora devel mailing list:

https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/thread/OAD6BEN6UMVIXAEI5EDS5COUYFSPNLZN/

I have posted results of your investigations there and I think Jeff Law will be back soon with some advice/fix.

vo.x (Vit Ondruch) wrote in #note-4:

Thank you for the investigation. There is a whole thread on Fedora devel mailing list:

https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/thread/OAD6BEN6UMVIXAEI5EDS5COUYFSPNLZN/

I have posted results of your investigations there

This is the link:

https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/message/NLQBH6N6GK53T4CC5CM2SWQEPYGS2CMR/

and I think Jeff Law will be back soon with some advice/fix.

This is still unresolved :(

And it seems that the DWARF is in better shape:

$ nm ./miniruby | grep -w rb_f_kill 00000000001ddcf0 T rb_f_kill 000000000002bd88 t rb_f_kill.cold $ nm ./miniruby | grep -w rb_f_kill | addr2line -e ./miniruby /builddir/build/BUILD/ruby-3.0.2/signal.c:424 /builddir/build/BUILD/ruby-3.0.2/numeric.c:2980 

Now I can reproduce this on my qemu-user-emulated powerpc64le-linux-musl environment:

$ powerpc64le-musl-qemu -strace ./miniruby -e 'Process.kill :SEGV, $$' (...) 24209 readlink("/proc/self/exe",0x0000004000490bd8,4096) = 75 24209 open("/var/tmp/ruby/xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/miniruby",O_RDONLY|O_LARGEFILE) = 5 24209 _llseek(5,0,0,0x0000004004160a70,SEEK_END) = 0 24209 _llseek(5,0,0,0x0000004004160a70,SEEK_SET) = 0 24209 mmap(NULL,24128544,PROT_READ,MAP_SHARED,5,0) = 0x000000400566b000 24209 close(5) = 0 --- SIGSEGV {si_signo=SIGSEGV, si_code=1, si_addr=NULL} --- qemu: uncaught target signal 11 (Segmentation fault) - core dumped Segmentation fault 

And it turns out that the patch attached in #note-9 is not enough to resolve this. I'm going to try to debug addr2line.c further.

Aren't there any subtle differences in GDB outputs? If fixed as intended, the value of abstract_origin can't get such large as 760312297580551 (0x2b380006a6807).

This is the GDB output:

(gdb) r Starting program: /builddir/build/BUILD/ruby-3.0.2/miniruby -e Process.kill\ :SEGV,\ \$\$ 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-4.4.25-1.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. 0x000000010031fb00 in uleb128 (p=0x1005986c0) at addr2line.c:200 200	unsigned char b = *(unsigned char *)(*p)++; (gdb) bt #0 0x000000010031fb00 in uleb128 (p=0x1005986c0) at addr2line.c:200 #1 di_read_die (reader=0x100598668, die=0x100598578) at addr2line.c:1343 #2 0x00000001003379a8 in debug_info_read (traces=<optimized out>, offset=<optimized out>, lines=<optimized out>, num_traces=<optimized out>, reader=<optimized out>) at addr2line.c:1650 #3 fill_lines (num_traces=num_traces@entry=19, check_debuglink=check_debuglink@entry=1, objp=0x100599010, objp@entry=0x1005990a0, lines=lines@entry=0x1005e2c20, offset=0, offset@entry=-1, traces=<optimized out>) at addr2line.c:1907 #4 0x0000000100338cfc in rb_dump_backtrace_with_lines.constprop.0 (num_traces=<optimized out>, traces=<optimized out>) at addr2line.c:2306 #5 0x000000010031df2c in rb_print_backtrace () at vm_dump.c:760 #6 0x0000000100335668 in rb_vm_bugreport.constprop.0 (ctx=<optimized out>) at vm_dump.c:998 #7 0x00000001000cd8a4 in rb_bug_for_fatal_signal (default_sighandler=0x0, sig=<optimized out>, ctx=<optimized out>, fmt=0x100383a78 "Segmentation fault at %p") at error.c:786 #8 0x00000001002562e8 in sigsegv (sig=<optimized out>, info=0x10059a330, ctx=0x1005995b0) at signal.c:960 #9 <signal handler called> #10 0x00007ffff7aa8810 in kill () from /lib64/libc.so.6 #11 0x000000010025acd0 in rb_f_kill (argc=<optimized out>, argv=0x7ffff78e0050) at signal.c:439 #12 0x00000001001fb3a8 in proc_rb_f_kill (c=<optimized out>, v=<optimized out>, _=<optimized out>) at process.c:8605 #13 0x00000001002e9238 in ractor_safe_call_cfunc_m1 (recv=<optimized out>, argc=<optimized out>, argv=<optimized out>, func=<optimized out>) at vm_insnhelper.c:2739 #14 0x00000001002f2080 in vm_call_cfunc_with_frame (ec=0x100491ac0, reg_cfp=0x7fffffffe170, calling=<optimized out>) at vm_insnhelper.c:2929 #15 0x00000001002f4e94 in vm_sendish (ec=0x100491ac0, reg_cfp=0x7ffff79dffa0, cd=0x1005c2e80, block_handler=<optimized out>, method_explorer=<optimized out>) at vm_insnhelper.c:4530 #16 0x00000001002fa20c in vm_exec_core (ec=0x100491ac0, initial=<optimized out>) at insns.def:789 #17 0x0000000100315140 in rb_vm_exec (ec=0x100491ac0, mjit_enable_p=<optimized out>) at vm.c:2172 #18 0x0000000100316f80 in rb_iseq_eval_main (iseq=0x1004a9fd8) at vm.c:2420 #19 0x00000001000d7c6c in rb_ec_exec_node (ec=ec@entry=0x100491ac0, n=n@entry=0x1004a9fd8) at eval.c:317 #20 0x00000001000d7dd4 in ruby_run_node (n=0x1004a9fd8) at eval.c:375 #21 0x000000010002afb8 in main (argc=<optimized out>, argv=<optimized out>) at ./main.c:50 (gdb) l uleb128 file: "addr2line.c", line number: 195, symbol: "uleb128" 190 191	/* Avoid consuming stack as this module may be used from signal handler */ 192	static char binary_filename[PATH_MAX + 1]; 193 194	static unsigned long 195	uleb128(char **p) 196	{ 197 unsigned long r = 0; 198 int s = 0; 199 for (;;) { file: "addr2line.c", line number: 197, symbol: "uleb128" 192	static char binary_filename[PATH_MAX + 1]; 193 194	static unsigned long 195	uleb128(char **p) 196	{ 197 unsigned long r = 0; 198 int s = 0; 199 for (;;) { 200	unsigned char b = *(unsigned char *)(*p)++; 201	if (b < 0x80) { file: "addr2line.c", line number: 200, symbol: "uleb128" 195	uleb128(char **p) 196	{ 197 unsigned long r = 0; 198 int s = 0; 199 for (;;) { 200	unsigned char b = *(unsigned char *)(*p)++; 201	if (b < 0x80) { 202 r += (unsigned long)b << s; 203 break; 204	} file: "addr2line.c", line number: 201, symbol: "uleb128" 196	{ 197 unsigned long r = 0; 198 int s = 0; 199 for (;;) { 200	unsigned char b = *(unsigned char *)(*p)++; 201	if (b < 0x80) { 202 r += (unsigned long)b << s; 203 break; 204	} 205	r += (b & 0x7f) << s; (gdb) 206	s += 7; 207 } 208 return r; 209	} 210 211	static long 212	sleb128(char **p) 213	{ 214 long r = 0; 215 int s = 0; (gdb) l di_read_die 1328	} 1329	#endif 1330 1331	static DIE * 1332	di_read_die(DebugInfoReader *reader, DIE *die) 1333	{ 1334 uint64_t abbrev_number = uleb128(&reader->p); 1335 if (abbrev_number == 0) { 1336 reader->level--; 1337 return NULL; (gdb) 1338 } 1339 1340 reader->q = di_find_abbrev(reader, abbrev_number); 1341 1342 die->pos = reader->p - reader->obj->debug_info.ptr - 1; 1343 die->tag = (int)uleb128(&reader->q); /* tag */ 1344 die->has_children = *reader->q++; /* has_children */ 1345 if (die->has_children) { 1346 reader->level++; 1347 } (gdb) 1348 return die; 1349	} 1350 1351	static DebugInfoValue * 1352	di_read_record(DebugInfoReader *reader, DebugInfoValue *vp) 1353	{ 1354 uint64_t at = uleb128(&reader->q); 1355 uint64_t form = uleb128(&reader->q); 1356 if (!at || !form) return NULL; 1357 vp->at = at; (gdb) l debug_info_read 1643	debug_info_read(DebugInfoReader *reader, int num_traces, void **traces, 1644 line_info_t *lines, int offset) { 1645 while (reader->p < reader->cu_end) { 1646 DIE die; 1647 ranges_t ranges = {}; 1648 line_info_t line = {}; 1649 1650 if (!di_read_die(reader, &die)) continue; 1651 /* fprintf(stderr,"%d:%tx: <%d>\n",__LINE__,die.pos,reader->level,die.tag); */ 1652 (gdb) 1653 if (die.tag != DW_TAG_subprogram && die.tag != DW_TAG_inlined_subroutine) { 1654 skip_die: 1655 di_skip_records(reader); 1656 continue; 1657 } 1658 1659 /* enumerate abbrev */ 1660 for (;;) { 1661 DebugInfoValue v = {{}}; 1662 /* ptrdiff_t pos = reader->p - reader->p0; */ (gdb) 1663 if (!di_read_record(reader, &v)) break; 1664 /* fprintf(stderr,"\n%d:%tx: AT:%lx FORM:%lx\n",__LINE__,pos,v.at,v.form); */ 1665 /* div_inspect(&v); */ 1666 switch (v.at) { 1667 case DW_AT_name: 1668 line.sname = get_cstr_value(&v); 1669 break; 1670 case DW_AT_call_file: 1671 fill_filename((int)v.as.uint64, reader->debug_line_directories, reader->debug_line_files, &line, reader->obj); 1672 break; (gdb) 1673 case DW_AT_call_line: 1674 line.line = (int)v.as.uint64; 1675 break; 1676 case DW_AT_low_pc: 1677 case DW_AT_high_pc: 1678 case DW_AT_ranges: 1679 ranges_set(&ranges, &v); 1680 break; 1681 case DW_AT_declaration: 1682 goto skip_die; (gdb) 1683 case DW_AT_inline: 1684 /* 1 or 3 */ 1685 break; /* goto skip_die; */ 1686 case DW_AT_abstract_origin: 1687 read_abstract_origin(reader, v.form, v.as.uint64, &line); 1688 break; /* goto skip_die; */ 1689 } 1690 } 1691 /* ranges_inspect(reader, &ranges); */ 1692 /* fprintf(stderr,"%d:%tx: %x ",__LINE__,diepos,die.tag); */ (gdb) 1693 for (int i=offset; i < num_traces; i++) { 1694 uintptr_t addr = (uintptr_t)traces[i]; 1695 uintptr_t offset = addr - reader->obj->base_addr + reader->obj->vmaddr; 1696 uintptr_t saddr = ranges_include(reader, &ranges, offset); 1697 if (saddr) { 1698 /* fprintf(stderr, "%d:%tx: %d %lx->%lx %x %s: %s/%s %d %s %s %s\n",__LINE__,die.pos, i,addr,offset, die.tag,line.sname,line.dirname,line.filename,line.line,reader->obj->path,line.sname,lines[i].sname); */ 1699 if (lines[i].sname) { 1700 line_info_t *lp = malloc(sizeof(line_info_t)); 1701 memcpy(lp, &lines[i], sizeof(line_info_t)); 1702 lines[i].next = lp; (gdb) 1703 lp->dirname = line.dirname; 1704 lp->filename = line.filename; 1705 lp->line = line.line; 1706 lp->saddr = 0; 1707 } 1708 lines[i].path = reader->obj->path; 1709 lines[i].base_addr = line.base_addr; 1710 lines[i].sname = line.sname; 1711 lines[i].saddr = saddr + reader->obj->base_addr - reader->obj->vmaddr; 1712 } (gdb) 1713 } 1714 } 1715	} 1716 1717	#ifdef USE_ELF 1718	static unsigned long 1719	uncompress_debug_section(ElfW(Shdr) *shdr, char *file, char **ptr) 1720	{ 1721	#ifdef SUPPORT_COMPRESSED_DEBUG_LINE 1722 ElfW(Chdr) *chdr = (ElfW(Chdr) *)(file + shdr->sh_offset); (gdb) 

Ah, I can see there is missing the read_abstract_origin on the backtrace.

FWIW, another bug is found in addr2line.c (#18081), which I believe is irrevant to the issue here, though.

The result with the latest patch is significantly different:

$ gdb --args ./miniruby -e'Process.kill("SIGSEGV",$$)' GNU gdb (GDB) Fedora 10.2-6.fc35 Copyright (C) 2021 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. 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/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... 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-4.4.25-1.fc35.ppc64le zlib-1.2.11-30.fc35.ppc64le (gdb) c Continuing. -e:1: [BUG] Segmentation fault at 0x590fb15c00000020 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 ------------------------------------------- 1267: Abbrev Number 106 not found Program received signal SIGABRT, Aborted. 0x00007ffff7b09864 in __pthread_kill_internal () from /lib64/libc.so.6 (gdb) bt #0 0x00007ffff7b09864 in __pthread_kill_internal () from /lib64/libc.so.6 #1 0x00007ffff7aa848c in raise () from /lib64/libc.so.6 #2 0x00007ffff7a81404 in abort () from /lib64/libc.so.6 #3 0x000000010031fe70 in di_abbrev_table (abbrev_number=106, reader=0x100598660) at addr2line.c:1268 #4 di_find_abbrev (abbrev_number=106, reader=0x100598660) at addr2line.c:1279 #5 di_read_die (reader=0x100598660, die=0x100598570) at addr2line.c:1349 #6 0x0000000100337a3c in debug_info_read (traces=<optimized out>, offset=<optimized out>, lines=<optimized out>, num_traces=<optimized out>, reader=<optimized out>) at addr2line.c:1658 #7 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:1915 #8 0x0000000100338d9c in rb_dump_backtrace_with_lines.constprop.0 (num_traces=<optimized out>, traces=<optimized out>) at addr2line.c:2314 #9 0x000000010031e04c in rb_print_backtrace () at vm_dump.c:760 #10 0x00000001003353d8 in rb_vm_bugreport.constprop.0 (ctx=<optimized out>) at vm_dump.c:998 #11 0x00000001000cd884 in rb_bug_for_fatal_signal (default_sighandler=0x0, sig=<optimized out>, ctx=<optimized out>, fmt=0x100383b18 "Segmentation fault at %p") at error.c:786 #12 0x00000001002563c8 in sigsegv (sig=<optimized out>, info=0x10059a330, ctx=0x1005995b0) at signal.c:960 #13 <signal handler called> #14 0x00007ffff7aa8810 in kill () from /lib64/libc.so.6 #15 0x000000010025adb0 in rb_f_kill (argc=<optimized out>, argv=0x7ffff78e0050) at signal.c:439 #16 0x00000001001fb488 in proc_rb_f_kill (c=<optimized out>, v=<optimized out>, _=<optimized out>) at process.c:8605 #17 0x00000001002e9358 in ractor_safe_call_cfunc_m1 (recv=<optimized out>, argc=<optimized out>, argv=<optimized out>, func=<optimized out>) at vm_insnhelper.c:2739 #18 0x00000001002f21a0 in vm_call_cfunc_with_frame (ec=0x100491ac0, reg_cfp=0x7fffffffe170, calling=<optimized out>) at vm_insnhelper.c:2929 #19 0x00000001002f4fb4 in vm_sendish (ec=0x100491ac0, reg_cfp=0x7ffff79dffa0, cd=0x1005c2eb0, block_handler=<optimized out>, method_explorer=<optimized out>) at vm_insnhelper.c:4530 #20 0x00000001002fa32c in vm_exec_core (ec=0x100491ac0, initial=<optimized out>) at insns.def:789 #21 0x0000000100315260 in rb_vm_exec (ec=0x100491ac0, mjit_enable_p=<optimized out>) at vm.c:2172 #22 0x00000001003170a0 in rb_iseq_eval_main (iseq=0x1004a9fb0) at vm.c:2420 #23 0x00000001000d7c4c in rb_ec_exec_node (ec=ec@entry=0x100491ac0, n=n@entry=0x1004a9fb0) at eval.c:317 #24 0x00000001000d7db4 in ruby_run_node (n=0x1004a9fb0) at eval.c:375 #25 0x000000010002afb8 in main (argc=<optimized out>, argv=<optimized out>) at ./main.c:50 (gdb) 

But probably still not the right output though. I'd still expect some backtrace reported.

The message

1267: Abbrev Number 106 not found 

means that addr2line.c could not find an abbrev table entry in .debug_abbrev referenced from .debug_info. Isn't it possible that either section is broken?

It might be helpful if can investigate those sections, in binary or objdump (from GNU Binutils) text output of

objdump -Wi miniruby objdump -Wa miniruby 

or llvm-dwarfdump output of

llvm-dwarfdump --debug-info miniruby llvm-dwarfdump --debug-abbrev miniruby 

xtkoba (Tee KOBAYASHI) wrote in #note-21:

Isn't it possible that either section is broken?

Well, it should be DWARF5, which is pretty recent and on ppc64le, so there might be some surprises ...

It might be helpful if can investigate those sections, in binary or objdump (from GNU Binutils) text output of

The dumps should be available here: https://vondruch.fedorapeople.org/objdump.tar.gz

vo.x (Vit Ondruch) wrote in #note-22:

The dumps should be available here: https://vondruch.fedorapeople.org/objdump.tar.gz

I'm afraid that this contains only .debug_info and not .debug_abbrev.

It seems that objdump can dump the .debug_info section without error, so maybe it is not broken. And of course it is probable that addr2line.c makes wrong assumptions on DWARF format.

I have recreated and reuploaded the tarball. Same URL should work.

(gdb) c Continuing. -e:1: [BUG] Segmentation fault at 0x590fb15c00000020 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 ------------------------------------------- 1273: debug_info 0x54 Abbrev Number 106 not found Program received signal SIGABRT, Aborted. 0x00007ffff7b09864 in __pthread_kill_internal () from /lib64/libc.so.6 (gdb) bt #0 0x00007ffff7b09864 in __pthread_kill_internal () from /lib64/libc.so.6 #1 0x00007ffff7aa848c in raise () from /lib64/libc.so.6 #2 0x00007ffff7a81404 in abort () from /lib64/libc.so.6 #3 0x000000010031fe70 in di_abbrev_table (abbrev_number=106, reader=0x100598660) at addr2line.c:1274 #4 di_find_abbrev (abbrev_number=106, reader=0x100598660) at addr2line.c:1285 #5 di_read_die (reader=0x100598660, die=0x100598570) at addr2line.c:1355 #6 0x00000001003370cc in debug_info_read (traces=<optimized out>, offset=<optimized out>, lines=<optimized out>, num_traces=<optimized out>, reader=<optimized out>) at addr2line.c:1664 #7 fill_lines (num_traces=num_traces@entry=19, check_debuglink=check_debuglink@entry=1, objp=0x100599010, objp@entry=0x1005990a0, lines=lines@entry=0x1005e2c50, offset=<optimized out>, offset@entry=-1, traces=<optimized out>) at addr2line.c:1929 #8 0x0000000100338dec in rb_dump_backtrace_with_lines.constprop.0 (num_traces=<optimized out>, traces=<optimized out>) at addr2line.c:2328 #9 0x000000010031e04c in rb_print_backtrace () at vm_dump.c:760 #10 0x0000000100335418 in rb_vm_bugreport.constprop.0 (ctx=<optimized out>) at vm_dump.c:998 #11 0x00000001000cd884 in rb_bug_for_fatal_signal (default_sighandler=0x0, sig=<optimized out>, ctx=<optimized out>, fmt=0x100383b58 "Segmentation fault at %p") at error.c:786 #12 0x0000000100256408 in sigsegv (sig=<optimized out>, info=0x10059a330, ctx=0x1005995b0) at signal.c:960 #13 <signal handler called> #14 0x00007ffff7aa8810 in kill () from /lib64/libc.so.6 #15 0x000000010025adf0 in rb_f_kill (argc=<optimized out>, argv=0x7ffff78e0050) at signal.c:439 #16 0x00000001001fb4c8 in proc_rb_f_kill (c=<optimized out>, v=<optimized out>, _=<optimized out>) at process.c:8605 #17 0x00000001002e9358 in ractor_safe_call_cfunc_m1 (recv=<optimized out>, argc=<optimized out>, argv=<optimized out>, func=<optimized out>) at vm_insnhelper.c:2739 #18 0x00000001002f21a0 in vm_call_cfunc_with_frame (ec=0x100491ac0, reg_cfp=0x7fffffffe170, calling=<optimized out>) at vm_insnhelper.c:2929 #19 0x00000001002f4fb4 in vm_sendish (ec=0x100491ac0, reg_cfp=0x7ffff79dffa0, cd=0x1005c2eb0, block_handler=<optimized out>, method_explorer=<optimized out>) at vm_insnhelper.c:4530 #20 0x00000001002fa32c in vm_exec_core (ec=0x100491ac0, initial=<optimized out>) at insns.def:789 #21 0x0000000100315260 in rb_vm_exec (ec=0x100491ac0, mjit_enable_p=<optimized out>) at vm.c:2172 #22 0x00000001003170a0 in rb_iseq_eval_main (iseq=0x1004a9fb0) at vm.c:2420 #23 0x00000001000d7c4c in rb_ec_exec_node (ec=ec@entry=0x100491ac0, n=n@entry=0x1004a9fb0) at eval.c:317 #24 0x00000001000d7db4 in ruby_run_node (n=0x1004a9fb0) at eval.c:375 #25 0x000000010002afb8 in main (argc=<optimized out>, argv=<optimized out>) at ./main.c:50 (gdb) f 3 #3 0x000000010031fe70 in di_abbrev_table (abbrev_number=106, reader=0x100598660) at addr2line.c:1274 1274 abort(); (gdb) l 1269 while (a) { 1270 len++; 1271 a >>= 7; 1272 } 1273 fprintf(stderr,"%d: debug_info 0x%"PRIxPTR" Abbrev Number %"PRId64" not found\n",__LINE__, reader->p - reader->obj->debug_info.ptr - len, abbrev_number); 1274 abort(); 1275 } 1276 return p; 1277	} 1278 (gdb) 

Byte 0x54 of the .debug_info is the 3rd byte of

 <52> DW_AT_abstract_origin: <0x6a6c3a> 

of the form DW_FORM_ref_addr which is in little endian 0x6a == 106 (and also the same value when interpreted as ULEB128). So apparently the executable misreads the .debug_info.

What feels weird to me is that my executable of miniruby has almost the same pattern as yours at the top portion of the .debug_info section, and yet does not cause any errors. Possibly addr2line.c is miscompiled in any way?

Just FTR, these are the build options:

gcc -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -mcpu=power8 -mtune=power8 -fasynchronous-unwind-tables -fstack-clash-protection -fPIC -m64 -D_FORTIFY_SOURCE=2 -fstack-protector-strong -fno-strict-overflow -fvisibility=hidden -fexcess-precision=standard -DRUBY_EXPORT -I. -I.ext/include/powerpc64le-linux -I./include -I. -I./enc/unicode/12.1.0 -o addr2line.o -c addr2line.c 

And the GCC version:

$ rpm -q gcc gcc-11.2.1-1.fc35.ppc64le $ gcc -v Using built-in specs. COLLECT_GCC=gcc COLLECT_LTO_WRAPPER=/usr/libexec/gcc/ppc64le-redhat-linux/11/lto-wrapper OFFLOAD_TARGET_NAMES=nvptx-none OFFLOAD_TARGET_DEFAULT=1 Target: ppc64le-redhat-linux Configured with: ../configure --enable-bootstrap --enable-languages=c,c++,fortran,objc,obj-c++,ada,go,lto --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-shared --enable-threads=posix --enable-checking=release --enable-targets=powerpcle-linux --disable-multilib --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-linker-build-id --with-gcc-major-version-only --with-linker-hash-style=gnu --enable-plugin --enable-initfini-array --with-isl=/builddir/build/BUILD/gcc-11.2.1-20210728/obj-ppc64le-redhat-linux/isl-install --enable-offload-targets=nvptx-none --without-cuda-driver --enable-gnu-indirect-function --enable-secureplt --with-long-double-128 --with-cpu-32=power8 --with-tune-32=power8 --with-cpu-64=power8 --with-tune-64=power8 --build=ppc64le-redhat-linux --with-build-config=bootstrap-lto --enable-link-serialization=1 Thread model: posix Supported LTO compression algorithms: zlib zstd gcc version 11.2.1 20210728 (Red Hat 11.2.1-1) (GCC) 

The behavior seems as if the patch in #note-9 (https://bugs.ruby-lang.org/attachments/8974) were not applied. If I reverse-apply this patch, yes I get the following output:

1300: debug_info 0x54 Abbrev Number 101 not found Aborted 

xtkoba (Tee KOBAYASHI) wrote in #note-29:

The behavior seems as if the patch in #note-9

Should it be applied? Based on the #note-10, #note-11 and #note-12, I thought that one is obsolete. That might be misunderstanding on my side, sorry. So let me add it into the mix (I have hig expectations now :D)

I might have been misleading. The patch in #note-9 is necessary for correctly reading DW_FORM_ref_addr values in .debug_info sections, even if those values are kept uninterpreted by the patch in #note-11. Both patches have been merged in master already. The rest of the patches I posted here won't be necessary.

xtkoba (Tee KOBAYASHI) wrote in #note-31:

I might have been misleading. The patch in #note-9 is necessary for correctly reading DW_FORM_ref_addr values in .debug_info sections, even if those values are kept uninterpreted by the patch in #note-11. Both patches have been merged in master already. The rest of the patches I posted here won't be necessary.

This is is the Fedora commit:

https://src.fedoraproject.org/rpms/ruby/c/1170d812fe0cd43aeddf7f15a63c2e6db3af8059

The two patches you have mentioned are enough to pass the test suite. I leave the rest to be backported eventually (BTW this was reported against Ruby 2.7 originally and it is likely still affected, but I don't think we are going to enable LTO for Ruby 2.7 at this stage, so the 2.7 backport is low priority for me).

So this is resolved from my POV unless you want to apply the ruby-addr2line-abbrev_table-r1.patch

Thx once again.

The situation ruby-addr2line-abbrev_table-r1.patch assumes is not likely to happen in the real world. Let's leave it unapplied for now. Thank you.

MEMO: Backporting 72317b333b85eed483ad00bcd4f40944019a7c13 depends on https://bugs.ruby-lang.org/issues/17585.