# SEGV by regexp match in while loop

**URL:** <https://www.ruby-forum.com/t/segv-by-regexp-match-in-while-loop/125040>\
**Category:** Development\
**Created:** [January 4, 2008, 7:29pm UTC](https://www.ruby-forum.com/t/segv-by-regexp-match-in-while-loop/125040 "2008-01-04T19:29:43Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\
**Post date:** [January 4, 2008, 7:29pm UTC](https://www.ruby-forum.com/t/segv-by-regexp-match-in-while-loop/125040/1 "2008-01-04T19:29:43Z")

</div>

Debian GNU/Linux (sarge) e$B$Ne(B gcc-3.4 e$B$r;H$C$F%S%k%I$7$?e(B ruby  
e$B$G!"0J2\<$N$h$&$K$9$k$He(B SEGV e$B$7$^$9!#e(B

% svn co [http://svn.ruby-lang.org/repos/ruby/trunk](http://svn.ruby-lang.org/repos/ruby/trunk) ruby  
…  
% autoconf  
% ./configure --prefix=/tmp/a CC=gcc-3.4  
…  
% make  
…  
% ./miniruby -ve ‘while true; /a/ =~ “a”; end’  
ruby 1.9.0 (2008-01-05 revision 0) [i686-linux]  
zsh: segmentation fault ./miniruby -ve ‘while true; /a/ =~ “a”; end’

e$B%9%?%C%/%5%$%:$rJQ$($k$HMn$A$k$^$G$N;~4V$,JQ$o$k$N$G$I$&$b%9e(B  
e$B%?%C%/%\*!\<%P!\<%U%m!\<$N$h$&$G$9!#e(B  
e$B;d$N;n$7$?4D6-$@$H!"%9%?%C%/%5%$%:e(B 8Mbytes e$B$N\>l9g?tIC$GMn$Ae(B  
e$B$^$9!#e(B

e$B0J2\<$O%9%?%C%/%5%$%:$re(B 2Mbytes e$B$H$7$FD4$Y$?$b$N$G$9!#e(B

% limit  
cputime unlimited  
filesize unlimited  
datasize unlimited  
stacksize 2MB  
coredumpsize 0kB  
memoryuse unlimited  
maxproc 27643  
descriptors 1024  
memorylocked 32kB  
addressspace unlimited  
maxfilelocks unlimited  
% gdb miniruby  
GNU gdb 6.3-debian  
Copyright 2004 Free Software Foundation, Inc.  
GDB is free software, covered by the GNU General Public License, and you  
are  
welcome to change it and/or distribute copies of it under certain  
conditions.  
Type “show copying” to see the conditions.  
There is absolutely no warranty for GDB. Type “show warranty” for  
details.  
This GDB was configured as “i386-linux”…Using host libthread\_db  
library “/lib/tls/libthread\_db.so.1”.

(gdb) run -ve ‘while true; /a/ =~ “a”; end’  
Starting program: /tmp/a/ruby/miniruby -ve ‘while true; /a/ =~ “a”; end’  
[Thread debugging using libthread\_db enabled]  
[New Thread -1210779968 (LWP 14167)]  
[New Thread -1211511888 (LWP 14170)]  
ruby 1.9.0 (2008-01-05 revision 0) [i686-linux]

Program received signal SIGSEGV, Segmentation fault.  
[Switching to Thread -1210779968 (LWP 14167)]  
match\_at (reg=0x81a7f18, str=0xb7ad5958 “a”, end=0xb7ad5959 “”,  
sstart=0xb7ad5958 “a”, sprev=0x0, msa=0xbf96bda0)  
at regexec.c:1290  
1290 STACK\_PUSH\_ENSURED(STK\_ALT, FinishCode); /\* bottom stack \*/

e$B%9%?%C%/%]%$%s%?6aJU$rD4$Y$F$\_$k$H$?$7$+$K%a%b%j$,ES@Z$l$F$$e(B  
e$B$k$h$&$G$9!#e(B

(gdb) p $sp  
$1 = (void \*) 0xbf96afe0  
(gdb) x $sp  
0xbf96afe0: Cannot access memory at address 0xbf96afe0  
(gdb) x $sp+1  
0xbf96afe1: Cannot access memory at address 0xbf96afe1  
(gdb) x $sp+4  
0xbf96afe4: Cannot access memory at address 0xbf96afe4  
(gdb) x $sp+10  
0xbf96afea: Cannot access memory at address 0xbf96afea  
(gdb) x $sp+100  
0xbf96b044: 0x08164f44

e$B$7$+$7!"%P%C%/%H%l!\<%9$r8+$k$H$=$l$[$I%9%?%C%/$r\>CHq$7$F$$$ke(B  
e$B$h$&$K$O8+$($^$;$s!#e(B

(gdb) bt  
#0 match\_at (reg=0x81a7f18, str=0xb7ad5958 “a”, end=0xb7ad5959 “”,  
sstart=0xb7ad5958 “a”, sprev=0x0, msa=0xbf96bda0)  
at regexec.c:1290  
#1 0x080cd9e5 in onig\_search (reg=0x81a7f18, str=0xb7ad5958 “a”,  
end=0xb7ad5959 “”, start=0xbf96bda0 “”,  
range=0xb7ad5959 “”, region=0x8164f24, option=0) at regexec.c:3608  
#2 0x080bdbf3 in rb\_reg\_search (re=3083514820, str=3081591120, pos=0,  
reverse=0) at re.c:1069  
#3 0x080be85d in reg\_match\_pos (re=3083514820, strp=0xbf96bed4, pos=0)  
at re.c:2209  
#4 0x080be8c3 in rb\_reg\_match (re=0, str=3081591120) at re.c:2256  
#5 0x08109a85 in vm\_eval (th=0x8168160, initial=0) at insns.def:2014  
#6 0x0810f3d0 in vm\_eval\_body (th=0x8168160) at vm.c:1148  
#7 0x08110e83 in rb\_iseq\_eval (iseqval=3083514180) at vm.c:1357  
#8 0x08070b9f in ruby\_exec\_node (n=0xb7cab324, file=0x81a71b1 “-e”) at  
eval.c:229  
#9 0x08074099 in ruby\_run\_node (n=0xb7cab324) at eval.c:259  
#10 0x080584f0 in main (argc=3, argv=0xbfb68df4, envp=0xbfb68e04) at  
main.c:36

e$B3F%9%?%C%/%U%l!\<%`$rD4$Y$F$_$k$H!"$I$&$b!"e(Bvm_eval e$B$N%9%?%C%/e(B e$B%U%l!<%`$,7c$7$/Bg$-$$$h$&$G$9!#e(B

(gdb) up  
#1 0x080cd9e5 in onig\_search (reg=0x81a7f18, str=0xb7ad5958  
“a”, end=0xb7ad5959 “”, start=0xbf96bda0 “”,  
range=0xb7ad5959 “”, region=0x8164f24, option=0) at  
regexec.c:3608  
3608 MATCH\_AND\_RETURN\_CHECK(orig\_range);  
(gdb)  
#2 0x080bdbf3 in rb\_reg\_search (re=3083514820,  
str=3081591120, pos=0, reverse=0) at re.c:1069  
1069 result = onig\_search(RREGEXP(re)-\>ptr,  
(gdb)  
#3 0x080be85d in reg\_match\_pos (re=3083514820,  
strp=0xbf96bed4, pos=0) at re.c:2209  
2209 return rb\_reg\_search(re, str, pos, 0);  
(gdb)  
#4 0x080be8c3 in rb\_reg\_match (re=0, str=3081591120) at  
re.c:2256  
2256 long pos = reg\_match\_pos(re, &str, 0);  
(gdb)  
#5 0x08109a85 in vm\_eval (th=0x8168160, initial=0) at  
insns.def:2014  
2014 val = rb\_reg\_match(r, obj);  
(gdb) p $sp  
$3 = (void \*) 0xbf96bed0  
(gdb) p $fp  
$4 = (void \*) 0xbfb68ab8  
(gdb) p $fp-$sp  
$5 = 2083816

e$BA[A|$9$k$K!"e(Bvm\_eval e$B$N%k!\<%W$NCf$G%9%?%C%/$r$I$s$I$sF0E\*$K3Ne(B  
e$BJ]$7$F$$$/$h$&$J$3$H$K$J$C$F$$$k$s$8$c$J$$$G$7$g$&$+!#e(B

e$B$J$\*!"e(BDebian GNU/Linux (etch) e$B$Ne(B gcc-3.4  
e$B$G$O:F8=$7$^$;$s$Ge(B  
e$B$7$?!#e(B

---

<div class="post-metadata">

**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\
**Post date:** [January 5, 2008, 11:23am UTC](https://www.ruby-forum.com/t/segv-by-regexp-match-in-while-loop/125040/2 "2008-01-05T11:23:59Z")

</div>

Gimitee$B$H$$$$$^$9!#e(B

[ruby-dev:32831]e$B$bF1$8860x$N$h$&$G$9!#e(B

$ gdb ruby19 ruby19.core  
GNU gdb 6.1.1 [FreeBSD]  
…  
#0 match\_at (reg=0x8276600, str=0x82d54ec " ", end=0x82d54ed “”,  
sstart=0x82d54ec " ", sprev=0x0, msa=0xbfa00730) at regexec.c:1288  
1288 STACK\_PUSH\_ENSURED(STK\_ALT, FinishCode); /\* bottom stack \*/  
[New Thread 0x8154300 (LWP 100131)]  
[New Thread 0x8154000 (LWP 100215)]  
(gdb) p $sp  
$1 = (void \*) 0xbf9ff960  
(gdb) x $sp  
0xbf9ff960: Cannot access memory at address 0xbf9ff960  
…  
(gdb) up  
#11 0x080d497d in vm\_eval (th=0x8156000, initial=0) at insns.def:1050  
1050 CALL\_METHOD(num, blockptr, flag, id, mn, recv, klass);  
(gdb) p $fp-$sp  
$12 = 2082248

08/01/05 e$B$Ke(B Tanaka A.[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) e$B$5$s$O=q$-$^$7$?e(B:

---

<div class="post-metadata">

**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\
**Post date:** [January 5, 2008, 11:45am UTC](https://www.ruby-forum.com/t/segv-by-regexp-match-in-while-loop/125040/3 "2008-01-05T11:45:38Z")

</div>

e$B!!$5$5$@$G$9!#e(B

Hiroshi Ichikawa wrote:

> Gimitee$B$H$$$$$^$9!#e(B
> 
> [ruby-dev:32831]e$B$bF1$8860x$N$h$&$G$9!#e(B
> 
> $ gdb ruby19 ruby19.core  
> GNU gdb 6.1.1 [FreeBSD]

e$B!!e(BIRC  
e$B$GEDCf$5$s$KHH?M$r65$($F$b$i$$$^$7$?!#$3$l$G$I$&$J$k$+;n$7$FLce(B  
e$B$($J$$$G$7$g$&$+!#e(B

# Index: vm.h

— vm.h (e$B%j%S%8%g%se(B 14893)  
+++ vm.h (e$B:n6H%3%T!\<e(B)  
@@ -144,7 +144,6 @@

/\* for GCC 3.4.x \*/  
#define TC\_DISPATCH(insn) \

- DISPATCH\_ARCH\_DEPEND\_WAY(GET\_CURRENT\_INSN());   
INSN\_DISPATCH\_SIG(insn);   
goto \*GET\_CURRENT\_INSN();   
;

---

<div class="post-metadata">

**Author:** ![Tanaka\_A](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/c67d28/32.png) [@Tanaka\_A](https://www.ruby-forum.com/u/Tanaka_A)\
**Post date:** [January 5, 2008, 1:53pm UTC](https://www.ruby-forum.com/t/segv-by-regexp-match-in-while-loop/125040/4 "2008-01-05T13:53:52Z")

</div>

Gimitee$B$G$9!#e(B

08/01/05 e$B$Ke(B SASADA Koichi[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) e$B$5$s$O=q$-$^$7$?e(B:

> e$B!!e(BIRC e$B$GEDCf$5$s$KHH?M$r65$($F$b$i$$$^$7$?!#$3$l$G$I$&$J$k$+;n$7$FLce(B  
> e$B$($J$$$G$7$g$&$+!#e(B

e$BMn$A$J$/$J$j$^$7$?!#$"$j$,$H$&$4$6$$$^$7$?!#e(B