# \[BUG\] Segmation fault in combination of heavy socket I/O and multi-threading

**URL:** <https://rubytalk.org/t/bug-segmation-fault-in-combination-of-heavy-socket-i-o-and-multi-threading/4730>\
**Category:** ruby-talk\
**Created:** [14 February 2003 12:22 UTC](https://rubytalk.org/t/bug-segmation-fault-in-combination-of-heavy-socket-i-o-and-multi-threading/4730 "2003-02-14T12:22:38Z")\
**Posts on this page:** 10\
**Page:** 1

<div class="post-metadata">

**Author:** ![Idan\_Sofer](https://avatars.discourse-cdn.com/v4/letter/i/d6d6ee/32.png) [@Idan\_Sofer](https://rubytalk.org/u/Idan_Sofer)\
**Post date:** [14 February 2003 12:22 UTC](https://rubytalk.org/t/bug-segmation-fault-in-combination-of-heavy-socket-i-o-and-multi-threading/4730/1 "2003-02-14T12:22:38Z")

</div>

This is one bug(Or perhaps even a set of bugs) I ran into more then once  
during the development of Radical, it is often solveable by forcing only  
one thread to run the inducer code concurrently, i.e. using  
Thread.critical or Mutex.

I had a problem reproducing the matter in simple TCP/IP snippets,  
however, I have managed reproducing it using a heavly stripped version  
of Radical, using pure ruby code(no extensions).

The initial way to reproduce the bug was using siege HTTP benchmarking  
tool available here:  
[http://www.joedog.org/siege/](http://www.joedog.org/siege/)  
(Or if you are using debian/gentoo you may use apt-get/emerge siege)

Then on one console:

# bzip2 -dc ruby-bug.tar.bz2|tar xv

# cd httpserve

# gdb ruby

> ruby ./radical.rb  
> Radical =\>

On the second console:  
siege -b -c 100 -t 120S -u [http://localhost:4000/blender](http://localhost:4000/blender)

Initially things will go right, but the response times will slowly rise,  
and after a while(less then a minute mostly) the interepter will crash  
in some manner.  
NOTE: In one occaction the interepter hanged and started mallocing like  
mad until it was killed by the kernel, so when performing this test  
please be aware the stability of your system might be in risk.

This is for instance one backtrace I was able to produce:  
Radical=\>  
Program received signal SIGSEGV, Segmentation fault.  
0x4103a618 in siglongjmp () from /lib/libc.so.6  
(gdb) bt  
#0 0x4103a618 in siglongjmp () from /lib/libc.so.6  
#1 0x41177b10 in rb\_thread\_restore\_context (th=0x4, exit=1) at eval.c:7567  
#2 0x41177927 in stack\_extend (th=0x0, exit=1074284600) at eval.c:7509  
#3 0x00001039 in ?? ()  
(gdb)

Another one:  
Radical=\>  
Program received signal SIGSEGV, Segmentation fault.  
0x4117799f in rb\_thread\_restore\_context (th=0x87f9878, exit=1) at  
eval.c:7533  
7533 eval.c: No such file or directory.  
in eval.c  
(gdb) bt  
#0 0x4117799f in rb\_thread\_restore\_context (th=0x87f9878, exit=1) at  
eval.c:7533  
#1 0x41177927 in stack\_extend (th=0x850da58, exit=1) at eval.c:7509  
#2 0x41177b10 in rb\_thread\_restore\_context (th=0x850da50, exit=1) at  
eval.c:7567  
#3 0x41177927 in stack\_extend (th=0x411c60c8, exit=43) at eval.c:7509

And number three:  
Radical=\>  
Program received signal SIGSEGV, Segmentation fault.  
0x4117f2fb in mark\_locations\_array (x=0xc0000000, n=-1073796479) at gc.c:353  
353 gc.c: No such file or directory.  
in gc.c  
(gdb) bt  
#0 0x4117f2fb in mark\_locations\_array (x=0xc0000000, n=-1073796479) at  
gc.c:353  
#1 0x4118007a in rb\_gc\_mark\_frame (frame=0x40cc2744) at gc.c:958  
#2 0x41177375 in thread\_mark (th=0x80b1ea0) at eval.c:7342  
#3 0x4117f908 in rb\_gc\_mark (ptr=0) at gc.c:676  
#4 0x4117f3eb in mark\_entry (key=12202, value=1074215600) at gc.c:446  
#5 0x411b5739 in st\_foreach (table=0x80b1ab0, func=0x4117f3d0  
\<mark\_entry\>, arg=0x0) at st.c:488  
#6 0x4117f41c in rb\_mark\_tbl (tbl=0xc0000000) at gc.c:455  
#7 0x4117f86a in rb\_gc\_mark (ptr=1092089970) at gc.c:650  
#8 0x4117f8a1 in rb\_gc\_mark (ptr=1092089970) at gc.c:659  
#9 0x4117f3eb in mark\_entry (key=12250, value=1074215900) at gc.c:446  
#10 0x411b5739 in st\_foreach (table=0x80a6198, func=0x4117f3d0  
\<mark\_entry\>, arg=0x0) at st.c:488  
#11 0x4117f41c in rb\_mark\_tbl (tbl=0xc0000000) at gc.c:455  
#12 0x4117f86a in rb\_gc\_mark (ptr=1092089970) at gc.c:650  
#13 0x4117f335 in mark\_locations\_array (x=0xbfff911c, n=1) at gc.c:419  
#14 0x4118007a in rb\_gc\_mark\_frame (frame=0xbfff9230) at gc.c:958  
#15 0x41180200 in rb\_gc () at gc.c:1034  
#16 0x4117ec65 in ruby\_xmalloc (size=16) at gc.c:94  
#17 0x411b4f87 in st\_init\_table\_with\_size (type=0x4117f872, size=11) at  
st.c:163  
#18 0x411b4fcd in st\_init\_table (type=0x411d9f54) at st.c:176  
#19 0x411b4ff3 in st\_init\_numtable () at st.c:182  
#20 0x411c1c0d in rb\_ivar\_set (obj=1074294420, id=12178, val=1074216020)  
at variable.c:958  
#21 0x4116ba24 in rb\_eval (self=1074294420, n=0x4117f872) at eval.c:2745  
#22 0x4116a65a in rb\_eval (self=1074294420, n=0x4117f872) at eval.c:2053  
#23 0x41170c4e in rb\_call0 (klass=1074217380, recv=1074294420, id=2865,  
argc=0, argv=0xbfff9568,  
body=0x4007836c, nosuper=0) at eval.c:4547  
#24 0x4117113c in rb\_call (klass=1074217380, recv=1074294420, mid=2865,  
argc=2, argv=0xbfff9560,  
scope=1) at eval.c:4640  
#25 0x4117148d in rb\_funcall2 (recv=3221225472, mid=2865, argc=2,  
argv=0xbfff9560) at ruby.h:574  
#26 0x411737e1 in rb\_obj\_call\_init (obj=1074294420, argc=2,  
argv=0xbfff9560) at eval.c:5726  
#27 0x41173832 in rb\_class\_new\_instance (argc=2, argv=0xbfff9560,  
klass=3221197592) at eval.c:5742  
#28 0x4117058d in call\_cfunc (func=0x411737f0 \<rb\_class\_new\_instance\>,  
recv=1074217380,  
len=-1073741824, argc=2, argv=0x0) at eval.c:4276  
#29 0x41170929 in rb\_call0 (klass=1073999096, recv=1074217380, id=3177,  
argc=2, argv=0xbfff9560,  
body=0x4003dde4, nosuper=1) at eval.c:4416  
#30 0x4117113c in rb\_call (klass=1073999096, recv=1074217380, mid=3177,  
argc=2, argv=0xbfff9560,  
scope=0) at eval.c:4640  
#31 0x4116c012 in rb\_eval (self=1074216020, n=0xbfff9318) at eval.c:2556  
#32 0x4116c0eb in rb\_eval (self=1074216020, n=0xbfff9318) at ruby.h:579  
#33 0x4116a65a in rb\_eval (self=1074216020, n=0xbfff9318) at eval.c:2053  
#34 0x4116a65a in rb\_eval (self=1074216020, n=0xbfff9318) at eval.c:2053  
#35 0x4116aedb in rb\_eval (self=1074216020, n=0xbfff9318) at eval.c:2237  
#36 0x4116eccd in rb\_yield\_0 (val=6, self=1074216020, klass=0, acheck=2)  
at eval.c:3644  
#37 0x41179a13 in rb\_thread\_yield (arg=1074215380, th=0x80b8450) at  
eval.c:8592  
#38 0x411798f1 in rb\_thread\_start\_0 (fn=0x411799dc \<rb\_thread\_yield\>,  
arg=0x400739d4,  
th\_arg=0xbfff9318) at eval.c:8525  
#39 0x41179ac0 in rb\_thread\_initialize (thread=1074215400,  
args=1074215380) at eval.c:8621  
#40 0x4117058d in call\_cfunc (func=0x41179a88 \<rb\_thread\_initialize\>,  
recv=1074215400,  
len=-1073741824, argc=0, argv=0x0) at eval.c:4276  
#41 0x41170929 in rb\_call0 (klass=1073978296, recv=1074215400, id=2865,  
argc=0, argv=0x0,  
body=0x40039b68, nosuper=1) at eval.c:4416  
#42 0x4117113c in rb\_call (klass=1073978296, recv=1074215400, mid=2865,  
argc=0, argv=0x0, scope=1)  
at eval.c:4640  
#43 0x4117148d in rb\_funcall2 (recv=3221225472, mid=2865, argc=0,  
argv=0x0) at ruby.h:574  
#44 0x411737e1 in rb\_obj\_call\_init (obj=1074215400, argc=0, argv=0x0) at  
eval.c:5726  
#45 0x41179a4c in rb\_thread\_s\_new (argc=0, argv=0x0, klass=1073978296)  
at eval.c:8605  
#46 0x4117058d in call\_cfunc (func=0x41179a18 \<rb\_thread\_s\_new\>,  
recv=1073978296,  
len=-1073741824, argc=0, argv=0x0) at eval.c:4276  
#47 0x41170929 in rb\_call0 (klass=1073978276, recv=1073978296, id=3177,  
argc=0, argv=0x0,  
body=0x40039b90, nosuper=1) at eval.c:4416  
#48 0x4117113c in rb\_call (klass=1073978276, recv=1073978296, mid=3177,  
argc=0, argv=0x0, scope=0)  
at eval.c:4640  
#49 0x4116c012 in rb\_eval (self=1074216020, n=0xbfffb668) at eval.c:2556  
#50 0x4116b3cd in rb\_eval (self=1074216020, n=0xbfffb668) at eval.c:2304  
#51 0x4116ba0c in rb\_eval (self=1074216020, n=0xbfffb668) at eval.c:2744  
#52 0x4116a65a in rb\_eval (self=1074216020, n=0xbfffb668) at eval.c:2053  
#53 0x41170c4e in rb\_call0 (klass=1074217300, recv=1074216020, id=5633,  
argc=0, argv=0xbfffd094,  
body=0x40075f90, nosuper=0) at eval.c:4547  
#54 0x4117113c in rb\_call (klass=1074217300, recv=1074216020, mid=5633,  
argc=1, argv=0xbfffd090,  
scope=1) at eval.c:4640  
#55 0x4116c012 in rb\_eval (self=1074216020, n=0xbfffb668) at eval.c:2556  
#56 0x41170c4e in rb\_call0 (klass=1074216180, recv=1074216020, id=2865,  
argc=0, argv=0xbfffda98,  
body=0x4007aff4, nosuper=0) at eval.c:4547  
#57 0x4117113c in rb\_call (klass=1074216180, recv=1074216020, mid=2865,  
argc=6, argv=0xbfffda80,  
scope=1) at eval.c:4640  
#58 0x4117148d in rb\_funcall2 (recv=3221225472, mid=2865, argc=6,  
argv=0xbfffda80) at ruby.h:574  
#59 0x411737e1 in rb\_obj\_call\_init (obj=1074216020, argc=6,  
argv=0xbfffda80) at eval.c:5726  
#60 0x41173832 in rb\_class\_new\_instance (argc=6, argv=0xbfffda80,  
klass=3221215288) at eval.c:5742  
#61 0x4117058d in call\_cfunc (func=0x411737f0 \<rb\_class\_new\_instance\>,  
recv=1074216180,  
len=-1073741824, argc=6, argv=0x0) at eval.c:4276  
#62 0x41170929 in rb\_call0 (klass=1073999096, recv=1074216180, id=3177,  
argc=6, argv=0xbfffda80,  
body=0x4003dde4, nosuper=1) at eval.c:4416  
#63 0x4117113c in rb\_call (klass=1073999096, recv=1074216180, mid=3177,  
argc=6, argv=0xbfffda80,  
scope=0) at eval.c:4640  
#64 0x4116c012 in rb\_eval (self=1073994976, n=0xbfffd838) at eval.c:2556  
#65 0x4116c0eb in rb\_eval (self=1073994976, n=0xbfffd838) at ruby.h:579  
#66 0x4116eccd in rb\_yield\_0 (val=1074247100, self=1073994976, klass=0,  
acheck=0) at eval.c:3644  
#67 0x4116f004 in rb\_yield (val=1074247100) at eval.c:3732  
#68 0x4115baa3 in rb\_ary\_each (ary=1074247200) at array.c:630  
#69 0x4117058d in call\_cfunc (func=0x4115ba68 \<rb\_ary\_each\>,  
recv=1074247200, len=-1073741824,  
argc=0, argv=0x0) at eval.c:4276  
#70 0x41170929 in rb\_call0 (klass=1073970976, recv=1074247200, id=3577,  
argc=0, argv=0x0,  
body=0x40037b4c, nosuper=1) at eval.c:4416  
#71 0x4117113c in rb\_call (klass=1073970976, recv=1074247200, mid=3577,  
argc=0, argv=0x0, scope=0)  
at eval.c:4640  
#72 0x4116b283 in rb\_eval (self=1073994976, n=0xbfffd838) at ruby.h:574  
#73 0x4116a65a in rb\_eval (self=1073994976, n=0xbfffd838) at eval.c:2053  
#74 0x41168908 in ruby\_run () at eval.c:1230  
#75 0x080485b4 in main ()  
#76 0x410299f1 in \_\_libc\_start\_main () from /lib/libc.so.6

All of these gdb dumps are from ruby 1.6.8…

As an attempt to produce pure-ruby bug reproduction enviroment, I have  
written a simple http request flooder to fit the role of siege:  
require ‘net/http’  
x=Net::HTTP.new ‘localhost’,4000  
1.upto 15 do  
Thread.new do  
while 1  
x.get ‘/blender’  
end  
end  
end  
while 1  
sleep 1  
end

This code is also included in the tar/gz. however, running it may also  
cause the interepter to chock:  
Starting program: /usr/bin/ruby fetcher.rb

Program received signal SIGPIPE, Broken pipe.  
0x410cb934 in write () from /lib/libc.so.6  
(gdb)  
#0 0x410cb934 in write () from /lib/libc.so.6  
#1 0x41120ba0 in sys\_sigabbrev () from /lib/libc.so.6  
#2 0x41077161 in \_IO\_do\_write () from /lib/libc.so.6  
#3 0x410770c9 in \_IO\_do\_write () from /lib/libc.so.6  
#4 0x41077a02 in \_IO\_file\_sync () from /lib/libc.so.6  
#5 0x4106e4db in fflush () from /lib/libc.so.6  
#6 0x41183e70 in io\_fflush (f=0x80b2908, path=0x0) at io.c:216  
#7 0x41183ff7 in io\_write (io=134948688, str=1074343880) at io.c:262  
#8 0x4117058d in call\_cfunc (func=0x41183e8c \<io\_write\>,  
recv=1074355840, len=22, argc=1,  
argv=0x400a3000) at eval.c:4276  
#9 0x41170929 in rb\_call0 (klass=1073961256, recv=1074355840, id=6713,  
argc=1, argv=0xbfff2a00,  
body=0x400354a0, nosuper=1) at eval.c:4416  
#10 0x4117113c in rb\_call (klass=1073961256, recv=1074355840, mid=6713,  
argc=1, argv=0xbfff2a00,  
scope=0) at eval.c:4640  
#11 0x4116c012 in rb\_eval (self=1074357220, n=0xffffffe0) at eval.c:2556  
#12 0x4116b95b in rb\_eval (self=1074357220, n=0xffffffe0) at eval.c:2724  
#13 0x4116c0eb in rb\_eval (self=1074357220, n=0xffffffe0) at ruby.h:579  
#14 0x4116ba0c in rb\_eval (self=1074357220, n=0xffffffe0) at eval.c:2744  
#15 0x4116a65a in rb\_eval (self=1074357220, n=0xffffffe0) at eval.c:2053  
#16 0x41170c4e in rb\_call0 (klass=1074372060, recv=1074357220, id=11585,  
argc=0, argv=0xbfff4784,  
body=0x4009d734, nosuper=0) at eval.c:4547  
#17 0x4117113c in rb\_call (klass=1074372060, recv=1074357220, mid=11585,  
argc=1, argv=0xbfff4780,  
scope=1) at eval.c:4640  
#18 0x4116c012 in rb\_eval (self=1074357220, n=0xffffffe0) at eval.c:2556  
#19 0x4116eccd in rb\_yield\_0 (val=4, self=1074357220, klass=0, acheck=0)  
at eval.c:3644  
#20 0x4116c80f in rb\_eval (self=1074357220, n=0xffffffe0) at eval.c:2386  
#21 0x4116a65a in rb\_eval (self=1074357220, n=0xffffffe0) at eval.c:2053  
#22 0x41170c4e in rb\_call0 (klass=1074372060, recv=1074357220, id=11577,  
argc=0, argv=0x0,  
body=0x4009db80, nosuper=0) at eval.c:4547  
#23 0x4117113c in rb\_call (klass=1074372060, recv=1074357220, mid=11577,  
argc=0, argv=0x0,  
scope=1) at eval.c:4640  
#24 0x4116c012 in rb\_eval (self=1074357220, n=0xffffffe0) at eval.c:2556  
#25 0x4116b3cd in rb\_eval (self=1074357220, n=0xffffffe0) at eval.c:2304  
#26 0x41170c4e in rb\_call0 (klass=1074372060, recv=1074357220, id=10521,  
argc=0, argv=0xbfff6814,  
body=0x400a0768, nosuper=0) at eval.c:4547  
#27 0x4117113c in rb\_call (klass=1074372060, recv=1074357220, mid=10521,  
argc=1, argv=0xbfff6810,  
scope=0) at eval.c:4640  
#28 0x4116c012 in rb\_eval (self=1074347740, n=0xffffffe0) at eval.c:2556  
#29 0x4116eccd in rb\_yield\_0 (val=1074344300, self=1074347740, klass=0,  
acheck=0) at eval.c:3644  
#30 0x4116c80f in rb\_eval (self=1074347740, n=0xffffffe0) at eval.c:2386  
#31 0x4116eccd in rb\_yield\_0 (val=1074346060, self=1074347740, klass=0,  
acheck=0) at eval.c:3644  
#32 0x4116f004 in rb\_yield (val=1074346060) at eval.c:3732  
#33 0x41181bea in each\_pair\_i (key=4294967264, value=1074347520) at  
hash.c:591  
#34 0x411810ac in rb\_hash\_foreach\_iter (key=22, value=1074347520,  
arg=0xbfff77c0) at hash.c:131  
#35 0x411b5739 in st\_foreach (table=0x80a1920, func=0x41181074  
\<rb\_hash\_foreach\_iter\>,  
arg=0xbfff77c0 " \>\t@¼\e\030A") at st.c:488  
#36 0x4118110c in rb\_hash\_foreach\_call (arg=0x0) at hash.c:142  
#37 0x4116feb1 in rb\_ensure (b\_proc=0x411810e4 \<rb\_hash\_foreach\_call\>,  
data1=3221190592,  
e\_proc=0x41181118 \<rb\_hash\_foreach\_ensure\>, data2=1074347680) at  
eval.c:4064  
#38 0x411811b4 in rb\_hash\_foreach (hash=22, func=0, farg=0x0) at hash.c:173  
#39 0x41181c18 in rb\_hash\_each\_pair (hash=1074347680) at hash.c:599  
#40 0x4117058d in call\_cfunc (func=0x41181bf4 \<rb\_hash\_each\_pair\>,  
recv=1074347680, len=22,  
argc=0, argv=0x400a3000) at eval.c:4276  
#41 0x41170929 in rb\_call0 (klass=1073968196, recv=1074347680, id=3577,  
argc=0, argv=0x0,  
body=0x40037098, nosuper=1) at eval.c:4416  
#42 0x4117113c in rb\_call (klass=1073968196, recv=1074347680, mid=3577,  
argc=0, argv=0x0, scope=0)  
at eval.c:4640  
#43 0x4116c012 in rb\_eval (self=1074347740, n=0x0) at eval.c:2556  
#44 0x4116b3cd in rb\_eval (self=1074347740, n=0x0) at eval.c:2304  
#45 0x41170c4e in rb\_call0 (klass=1074362920, recv=1074347740, id=10241,  
argc=0, argv=0x0,  
body=0x400250b4, nosuper=0) at eval.c:4547  
#46 0x4117113c in rb\_call (klass=1074362920, recv=1074347740, mid=10241,  
argc=0, argv=0x0,  
scope=1) at eval.c:4640  
#47 0x4116c012 in rb\_eval (self=1074347740, n=0x0) at eval.c:2556  
#48 0x4116b3cd in rb\_eval (self=1074347740, n=0x0) at eval.c:2304  
#49 0x4116a65a in rb\_eval (self=1074347740, n=0x0) at eval.c:2053  
#50 0x41170c4e in rb\_call0 (klass=1074363880, recv=1074347740, id=9201,  
argc=0, argv=0xbfff993c,  
body=0x4002026c, nosuper=0) at eval.c:4547  
#51 0x4117113c in rb\_call (klass=1074363880, recv=1074347740, mid=9201,  
argc=3, argv=0xbfff9930,  
scope=1) at eval.c:4640  
#52 0x4116c012 in rb\_eval (self=1074347740, n=0x0) at eval.c:2556  
#53 0x41170c4e in rb\_call0 (klass=1074363880, recv=1074347740, id=8249,  
argc=0, argv=0xbfffa2f4,  
body=0x40020e88, nosuper=0) at eval.c:4547  
#54 0x4117113c in rb\_call (klass=1074363880, recv=1074347740, mid=8249,  
argc=4, argv=0xbfffa2e4,  
scope=1) at eval.c:4640  
#55 0x41171319 in rb\_f\_send (argc=4, argv=0xbfffa2e4, recv=1074347740)  
at ruby.h:574  
#56 0x4117058d in call\_cfunc (func=0x41171290 \<rb\_f\_send\>,  
recv=1074347740, len=22, argc=5,  
argv=0x400a3000) at eval.c:4276  
#57 0x41170929 in rb\_call0 (klass=1073998996, recv=1074347740, id=3641,  
argc=5, argv=0xbfffa2e0,  
body=0x4003d178, nosuper=1) at eval.c:4416  
#58 0x4117113c in rb\_call (klass=1073998996, recv=1074347740, mid=3641,  
argc=5, argv=0xbfffa2e0,  
scope=0) at eval.c:4640  
#59 0x4116c012 in rb\_eval (self=1074361880, n=0x0) at eval.c:2556  
#60 0x4116a65a in rb\_eval (self=1074361880, n=0x0) at eval.c:2053  
#61 0x41170c4e in rb\_call0 (klass=1074369700, recv=1074361880, id=9201,  
argc=0, argv=0xbfffafe4,  
body=0x40029bdc, nosuper=0) at eval.c:4547  
#62 0x4117113c in rb\_call (klass=1074369700, recv=1074361880, mid=9201,  
argc=1, argv=0xbfffafe0,  
scope=1) at eval.c:4640  
#63 0x4116c012 in rb\_eval (self=1074361880, n=0x0) at eval.c:2556  
#64 0x4116b3cd in rb\_eval (self=1074361880, n=0x0) at eval.c:2304  
#65 0x4116a65a in rb\_eval (self=1074361880, n=0x0) at eval.c:2053  
#66 0x41170c4e in rb\_call0 (klass=1074369700, recv=1074361880, id=9041,  
argc=0, argv=0xbfffc254,  
body=0x4002b9a0, nosuper=0) at eval.c:4547  
#67 0x4117113c in rb\_call (klass=1074369700, recv=1074361880, mid=9041,  
argc=1, argv=0xbfffc250,  
scope=0) at eval.c:4640  
#68 0x4116c012 in rb\_eval (self=1073994976, n=0x0) at eval.c:2556  
#69 0x4116aedb in rb\_eval (self=1073994976, n=0x0) at eval.c:2237  
#70 0x4116eccd in rb\_yield\_0 (val=6, self=1073994976, klass=0, acheck=2)  
at eval.c:3644  
#71 0x41179a13 in rb\_thread\_yield (arg=1074349820, th=0x80a1540) at  
eval.c:8592  
#72 0x411798f1 in rb\_thread\_start\_0 (fn=0x411799dc \<rb\_thread\_yield\>,  
arg=0x400946fc, th\_arg=0x0)  
at eval.c:8525  
#73 0x41179ac0 in rb\_thread\_initialize (thread=1074349880,  
args=1074349820) at eval.c:8621  
#74 0x4117058d in call\_cfunc (func=0x41179a88 \<rb\_thread\_initialize\>,  
recv=1074349880, len=22,  
argc=0, argv=0x400a3000) at eval.c:4276  
#75 0x41170929 in rb\_call0 (klass=1073978296, recv=1074349880, id=2865,  
argc=0, argv=0x0,  
body=0x40039b68, nosuper=1) at eval.c:4416  
#76 0x4117113c in rb\_call (klass=1073978296, recv=1074349880, mid=2865,  
argc=0, argv=0x0, scope=1)  
at eval.c:4640  
#77 0x4117148d in rb\_funcall2 (recv=22, mid=2865, argc=0, argv=0x0) at  
ruby.h:574  
#78 0x411737e1 in rb\_obj\_call\_init (obj=1074349880, argc=0, argv=0x0) at  
eval.c:5726  
#79 0x41179a4c in rb\_thread\_s\_new (argc=0, argv=0x0, klass=1073978296)  
at eval.c:8605  
#80 0x4117058d in call\_cfunc (func=0x41179a18 \<rb\_thread\_s\_new\>,  
recv=1073978296, len=22, argc=0,  
argv=0x400a3000) at eval.c:4276  
#81 0x41170929 in rb\_call0 (klass=1073978276, recv=1073978296, id=3177,  
argc=0, argv=0x0,  
body=0x40039b90, nosuper=1) at eval.c:4416  
#82 0x4117113c in rb\_call (klass=1073978276, recv=1073978296, mid=3177,  
argc=0, argv=0x0, scope=0)  
at eval.c:4640  
#83 0x4116c012 in rb\_eval (self=1073994976, n=0xbfffd2c8) at eval.c:2556  
#84 0x4116b3cd in rb\_eval (self=1073994976, n=0xbfffd2c8) at eval.c:2304  
#85 0x4116eccd in rb\_yield\_0 (val=21, self=1073994976, klass=0,  
acheck=0) at eval.c:3644  
body=0x40039b68, nosuper=1) at eval.c:4416  
#76 0x4117113c in rb\_call (klass=1073978296, recv=1074349880, mid=2865,  
argc=0, argv=0x0, scope=1)  
at eval.c:4640  
#77 0x4117148d in rb\_funcall2 (recv=22, mid=2865, argc=0, argv=0x0) at  
ruby.h:574  
#78 0x411737e1 in rb\_obj\_call\_init (obj=1074349880, argc=0, argv=0x0) at  
eval.c:5726  
#79 0x41179a4c in rb\_thread\_s\_new (argc=0, argv=0x0, klass=1073978296)  
at eval.c:8605  
#80 0x4117058d in call\_cfunc (func=0x41179a18 \<rb\_thread\_s\_new\>,  
recv=1073978296, len=22, argc=0,  
argv=0x400a3000) at eval.c:4276  
#81 0x41170929 in rb\_call0 (klass=1073978276, recv=1073978296, id=3177,  
argc=0, argv=0x0,  
body=0x40039b90, nosuper=1) at eval.c:4416  
#82 0x4117113c in rb\_call (klass=1073978276, recv=1073978296, mid=3177,  
argc=0, argv=0x0, scope=0)  
at eval.c:4640  
#83 0x4116c012 in rb\_eval (self=1073994976, n=0xbfffd2c8) at eval.c:2556  
#84 0x4116b3cd in rb\_eval (self=1073994976, n=0xbfffd2c8) at eval.c:2304  
#85 0x4116eccd in rb\_yield\_0 (val=21, self=1073994976, klass=0,  
acheck=0) at eval.c:3644  
—Type to continue, or q to quit—  
#86 0x4116f004 in rb\_yield (val=21) at eval.c:3732  
#87 0x4118fb5c in fix\_upto (from=3, to=3221213896) at numeric.c:1468  
#88 0x4117058d in call\_cfunc (func=0x4118fb0c \<fix\_upto\>, recv=3,  
len=22, argc=1, argv=0x400a3000)  
at eval.c:4276  
#89 0x41170929 in rb\_call0 (klass=1073975016, recv=3, id=4017, argc=1,  
argv=0xbfffe3e0,  
body=0x400389c0, nosuper=1) at eval.c:4416  
#90 0x4117113c in rb\_call (klass=1073975016, recv=3, mid=4017, argc=1,  
argv=0xbfffe3e0, scope=0)  
at eval.c:4640  
#91 0x4116c012 in rb\_eval (self=1073994976, n=0xbfffd2c8) at eval.c:2556  
#92 0x4116b3cd in rb\_eval (self=1073994976, n=0xbfffd2c8) at eval.c:2304  
#93 0x4116a65a in rb\_eval (self=1073994976, n=0xbfffd2c8) at eval.c:2053  
#94 0x41168908 in ruby\_run () at eval.c:1230  
#95 0x080485b4 in main ()  
#96 0x410299f1 in \_\_libc\_start\_main () from /lib/libc.so.6

I hope the provided information is enough, I have decided not to attach  
the test program here as it’s 21kb(and this message is already large  
enough without it), but it may be fetched here:  
[http://idanso.dyndns.org/maps/ruby-bug.tar.bz2](http://idanso.dyndns.org/maps/ruby-bug.tar.bz2)

Idan.

---

<div class="post-metadata">

**Author:** ![ts1](https://avatars.discourse-cdn.com/v4/letter/t/a8b319/32.png) [@ts1](https://rubytalk.org/u/ts1)\
**Post date:** [18 February 2003 18:22 UTC](https://rubytalk.org/t/bug-segmation-fault-in-combination-of-heavy-socket-i-o-and-multi-threading/4730/2 "2003-02-18T18:22:32Z")

</div>

> I had a problem reproducing the matter in simple TCP/IP snippets,  
> however, I have managed reproducing it using a heavly stripped version  
> of Radical, using pure ruby code(no extensions).

It receive VT\_ALRM when it's in rb\_thread\_restore\_context(). Can you try  
to put ruby in critical phase when it's in rb\_thread\_restore\_context() to  
see if there is a change.

Guy Decoux

---

<div class="post-metadata">

**Author:** ![ts1](https://avatars.discourse-cdn.com/v4/letter/t/a8b319/32.png) [@ts1](https://rubytalk.org/u/ts1)\
**Post date:** [19 February 2003 11:46 UTC](https://rubytalk.org/t/bug-segmation-fault-in-combination-of-heavy-socket-i-o-and-multi-threading/4730/3 "2003-02-19T11:46:16Z")

</div>

> It receive VT\_ALRM when it's in rb\_thread\_restore\_context(). Can you try  
> to put ruby in critical phase when it's in rb\_thread\_restore\_context() to  
> see if there is a change.

Well, for me the problem is solved

pigeon% siege -b -c 20 -t 120S -u [http://localhost:4000/blender](http://localhost:4000/blender)  
\*\* Siege 2.55  
\*\* Preparing 20 concurrent users for battle.  
The server is now under siege...  
Lifting the server siege... done.  
Transactions: 4697 hits  
Availability: 100.00 %  
Elapsed time: 119.93 secs  
Data transferred: 213736985 bytes  
Response time: 0.51 secs  
Transaction rate: 39.16 trans/sec  
Throughput: 1782181.14 bytes/sec  
Concurrency: 19.79  
Successful transactions: 4697  
Failed transactions: 0  
pigeon%

pigeon% siege -b -c 100 -t 120S -u [http://localhost:4000/blender](http://localhost:4000/blender)  
\*\* Siege 2.55  
\*\* Preparing 100 concurrent users for battle.  
The server is now under siege...  
Error: SIEGEsocket: connection timed out.: Operation now in progress  
[...]  
Error: SIEGEsocket: connection timed out.: Operation now in progress

Lifting the server siege.. done.  
Transactions: 5800 hits  
Availability: 99.59 %  
Elapsed time: 120.32 secs  
Data transferred: 263929000 bytes  
Response time: 1.86 secs  
Transaction rate: 48.20 trans/sec  
Throughput: 2193558.85 bytes/sec  
Concurrency: 89.44  
Successful transactions: 5800  
Failed transactions: 24  
pigeon%

Now if someone can explain me why it need this, I'll very happy ...

p.s. : you must have a bug in your source

Guy Decoux

---

<div class="post-metadata">

**Author:** ![Idan\_Sofer](https://avatars.discourse-cdn.com/v4/letter/i/d6d6ee/32.png) [@Idan\_Sofer](https://rubytalk.org/u/Idan_Sofer)\
**Post date:** [19 February 2003 14:37 UTC](https://rubytalk.org/t/bug-segmation-fault-in-combination-of-heavy-socket-i-o-and-multi-threading/4730/4 "2003-02-19T14:37:39Z")

</div>

ביום רביעי, 19 בפברואר 2003, 11:46, ts כתב:

> > It receive VT\_ALRM when it’s in rb\_thread\_restore\_context(). Can you  
> > try t\> to put ruby in critical phase when it’s in  
> > rb\_thread\_restore\_context() to t\> see if there is a change.
> 
> Well, for me the problem is solved  
> I suppose it is a change I have to apply to the ruby source itself?

In anyway according to the results you’ve sent it indeed appears to have  
solved the matter, many 10x.

> p.s. : you must have a bug in your source  
> ??

Idan

---

<div class="post-metadata">

**Author:** ![Robert\_McGovern2](https://avatars.discourse-cdn.com/v4/letter/r/838e76/32.png) [@Robert\_McGovern2](https://rubytalk.org/u/Robert_McGovern2)\
**Post date:** [19 February 2003 14:46 UTC](https://rubytalk.org/t/bug-segmation-fault-in-combination-of-heavy-socket-i-o-and-multi-threading/4730/5 "2003-02-19T14:46:07Z")

</div>

> > p.s. : you must have a bug in your source
> 
> ??  
> I think he was refering to the fact that example two had 5800  
> transactions, had 5800 successful transactions and there where 24 failed  
> transactions.

Lifting the server siege.. done. Transactions: 5800 hits Availability: 99.59 % Elapsed time: 120.32 secs Data transferred: 263929000 bytes Response time: 1.86 secs Transaction rate: 48.20 trans/sec Throughput: 2193558.85 bytes/sec Concurrency: 89.44 Successful transactions: 5800 Failed transactions: 24 \<\<------ problem?

---

<div class="post-metadata">

**Author:** ![ts1](https://avatars.discourse-cdn.com/v4/letter/t/a8b319/32.png) [@ts1](https://rubytalk.org/u/ts1)\
**Post date:** [19 February 2003 14:55 UTC](https://rubytalk.org/t/bug-segmation-fault-in-combination-of-heavy-socket-i-o-and-multi-threading/4730/6 "2003-02-19T14:55:48Z")

</div>

> I suppose it is a change I have to apply to the ruby source itself?

Yes, like I've said put rb\_thread\_restore\_context() in critical phase  
(same for rb\_thread\_save\_context()).

It's easy to understand :  
&nbsp;&nbsp;&nbsp;1) a thread is stopped by the timer  
&nbsp;&nbsp;&nbsp;2) ruby run the scheduler  
&nbsp;&nbsp;&nbsp;3) when ruby call rb\_thread\_restore\_context()  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\* it extend the stack (extend\_stack)  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\* the current thread is with rb\_trap\_immediate = 1  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;\* ruby receive VTALRM it re-run the scheduler, at this step the  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;frame pointers for this thread \*can\* be invalid (ruby has not yet  
&nbsp;&nbsp;&nbsp;make the complete copy)

Now if the new thread call the GC, it exist at least one thread with  
invalid frame pointers and you have the bug

#0 0x4117f2fb in mark\_locations\_array (x=0xc0000000, n=-1073796479) at gc.c:353  
#1 0x4118007a in rb\_gc\_mark\_frame (frame=0x40cc2744) at gc.c:958  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;^^^^^^^^^^^^^^^^  
this frame pointer is invalid.

> > p.s. : you must have a bug in your source
> 
> ??

Well, if I'm right it exist a possibility that your script will be blocked  
in a while loop and never accept new connection : not sure.

Guy Decoux

---

<div class="post-metadata">

**Author:** ![Nobuyoshi\_Nakada](https://avatars.discourse-cdn.com/v4/letter/n/edb3f5/32.png) [@Nobuyoshi\_Nakada](https://rubytalk.org/u/Nobuyoshi_Nakada)\
**Post date:** [19 February 2003 15:34 UTC](https://rubytalk.org/t/bug-segmation-fault-in-combination-of-heavy-socket-i-o-and-multi-threading/4730/7 "2003-02-19T15:34:58Z")

</div>

Hi,

> **···**
>
> At Wed, 19 Feb 2003 23:55:48 +0900, ts wrote:
> 
> > > I suppose it is a change I have to apply to the ruby source itself?
> > 
> > Yes, like I’ve said put rb\_thread\_restore\_context() in critical phase  
> > (same for rb\_thread\_save\_context()).
> > 
> > It’s easy to understand :
> > 
> > 1. a thread is stopped by the timer
> > 2. ruby run the scheduler
> > 3. when ruby call rb\_thread\_restore\_context()
> > - it extend the stack (extend\_stack)
> > - the current thread is with rb\_trap\_immediate = 1
> > - ruby receive VTALRM it re-run the scheduler, at this step the  
> > frame pointers for this thread _can_ be invalid (ruby has not yet  
> > make the complete copy)
> 
> What about this?
> 
> # Index: eval.c
> 
> RCS file: //sharui/cvs/ruby/src/ruby/eval.c,v  
> retrieving revision 1.398  
> diff -u -2 -p -r1.398 eval.c  
> — eval.c 19 Feb 2003 09:27:49 -0000 1.398  
> +++ eval.c 19 Feb 2003 15:32:13 -0000  
> @@ -7826,4 +7826,5 @@ thread\_switch(n)  
> int n;  
> {
> 
> - rb\_trap\_immediate = (curr\_thread-\>flags&0x100)?1:0;  
> switch (n) {  
> case 0:  
> @@ -7891,4 +7892,5 @@ rb\_thread\_restore\_context(th, exit)  
> }
> 
> - rb\_trap\_immediate = 0; /\* prohibit interrupts from here \*/  
> ruby\_frame = th-\>frame;  
> ruby\_scope = th-\>scope;  
> @@ -7899,5 +7901,4 @@ rb\_thread\_restore\_context(th, exit)  
> ruby\_block = th-\>block;  
> scope\_vmode = th-\>flags&SCOPE\_MASK;
> 
> - rb\_trap\_immediate = (th-\>flags&0x100)?1:0;  
> ruby\_iter = th-\>iter;  
> prot\_tag = th-\>tag;
> 
> –  
> Nobu Nakada

---

<div class="post-metadata">

**Author:** ![Idan\_Sofer](https://avatars.discourse-cdn.com/v4/letter/i/d6d6ee/32.png) [@Idan\_Sofer](https://rubytalk.org/u/Idan_Sofer)\
**Post date:** [19 February 2003 19:05 UTC](https://rubytalk.org/t/bug-segmation-fault-in-combination-of-heavy-socket-i-o-and-multi-threading/4730/8 "2003-02-19T19:05:12Z")

</div>

It’s not a bug but a feature:-)

The MTServer class does not start a thread for every request, but keeps a  
limited pool of worker threads, if i’m not mistaken the default setting is up  
to 10 workers and additional 10 workers employed during stress time.

So if you flood it with 100 concurrent clients, it is likely some of the  
requests will timeout…

Idan.

> **···**
>
> On יום רביעי, 19 בפברואר 2003, 16:46, Robert McGovern wrote:
> 
> > I think he was refering to the fact that example two had 5800  
> > transactions, had 5800 successful transactions and there where 24 failed  
> > transactions.  
> > Failed transactions: 24 \<\<------ problem?

---

<div class="post-metadata">

**Author:** ![ts1](https://avatars.discourse-cdn.com/v4/letter/t/a8b319/32.png) [@ts1](https://rubytalk.org/u/ts1)\
**Post date:** [19 February 2003 15:48 UTC](https://rubytalk.org/t/bug-segmation-fault-in-combination-of-heavy-socket-i-o-and-multi-threading/4730/9 "2003-02-19T15:48:41Z")

</div>

> What about this?

Seems good

Guy Decoux

---

<div class="post-metadata">

**Author:** ![Yukihiro\_Matsumoto2](https://avatars.discourse-cdn.com/v4/letter/y/b9e5f3/32.png) [@Yukihiro\_Matsumoto2](https://rubytalk.org/u/Yukihiro_Matsumoto2)\
**Post date:** [19 February 2003 16:17 UTC](https://rubytalk.org/t/bug-segmation-fault-in-combination-of-heavy-socket-i-o-and-multi-threading/4730/10 "2003-02-19T16:17:21Z")

</div>

Hi,

> **···**
>
> In message “Re: [BUG] Segmation fault in combination of heavy socket I/O and multi-threading” on 03/02/20, [nobu.nokada@softhome.net](mailto:nobu.nokada@softhome.net) [nobu.nokada@softhome.net](mailto:nobu.nokada@softhome.net) writes:
> 
> > What about this?
> 
> Go ahead and commit these fix, please
> 
> ```
> matz.
> 
> ```