# \[bug:trunk\] GNU/Linux select hang on a socket which TCP state is CLOSED

**URL:** <https://www.ruby-forum.com/t/bug-trunk-gnu-linux-select-hang-on-a-socket-which-tcp-state-is-closed/191149>\
**Category:** Development\
**Created:** [July 6, 2010, 3:23pm UTC](https://www.ruby-forum.com/t/bug-trunk-gnu-linux-select-hang-on-a-socket-which-tcp-state-is-closed/191149 "2010-07-06T15:23:05Z")\
**Posts on this page:** 7\
**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:** [July 6, 2010, 3:23pm UTC](https://www.ruby-forum.com/t/bug-trunk-gnu-linux-select-hang-on-a-socket-which-tcp-state-is-closed/191149/1 "2010-07-06T15:23:05Z")

</div>

GNU/Linux e$B$G!"0J2\<$N%W%m%0%i%`$,%O%s%0$7$^$9!#e(B

% uname -mrsv  
Linux 2.6.26-2-486 #1 Sat Dec 26 08:37:39 UTC 2009 i686  
% ./ruby -rsocket -ve ’  
BasicSocket.do\_not\_reverse\_lookup = true  
serv = TCPServer.open(“127.0.0.1”, 0)  
s1 = TCPSocket.open(“127.0.0.1”, serv.addr[1])  
s2 = serv.accept  
s2.close  
s1.write(“a”) rescue p $!  
s1.write(“a”) rescue p $!  
Thread.new {  
s1.write(“a”)  
}.join’  
ruby 1.9.3dev (2010-07-06 trunk 28554) [i686-linux]  
#\<Errno::EPIPE: Broken pipe\>  
e$B$3$3$G%O%s%0e(B

FreeBSD e$B$G$O%O%s%0$7$^$;$s!#e(B

% ./ruby -rsocket -ve ’  
BasicSocket.do\_not\_reverse\_lookup = true  
serv = TCPServer.open(“127.0.0.1”, 0)  
s1 = TCPSocket.open(“127.0.0.1”, serv.addr[1])  
s2 = serv.accept  
s2.close  
s1.write(“a”) rescue p $!  
s1.write(“a”) rescue p $!  
Thread.new {  
s1.write(“a”)  
}.join’  
ruby 1.9.3dev (2010-07-06 trunk 28554) [i386-freebsd8.0]  
#\<Errno::EPIPE: Broken pipe\>  
-e:10:in `write': Broken pipe (Errno::EPIPE) from -e:10:in`block in ’

e$B$^$!!"e(B[ruby-core:31065], [ruby-core:31068] e$B$NOC$J$s$G$9$,!#e(B

e$B$=$&$$$($P!“e(B[ruby-dev:34567]  
e$B$H$$$&$N$b$”$j$^$7$?$,F1$8$+$J!#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:** [July 6, 2010, 4:24pm UTC](https://www.ruby-forum.com/t/bug-trunk-gnu-linux-select-hang-on-a-socket-which-tcp-state-is-closed/191149/2 "2010-07-06T16:24:33Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:41833] [bug:trunk] GNU/Linux select hang on a  
socket which TCP state is CLOSED”  
on Tue, 6 Jul 2010 22:21:26 +0900, Tanaka A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|GNU/Linux e$B$G!"0J2\<$N%W%m%0%i%`$,%O%s%0$7$^$9!#e(B

|e$B$^$!!"e(B[ruby-core:31065], [ruby-core:31068] e$B$NOC$J$s$G$9$,!#e(B

e$B;vBV$,$h$/M}2r$G$-$F$J$$$s$G$9$,!“$3$l$Oe(BLinuxe$B$Ne(Bselecte$B$N5sF0e(B  
e$B$,$\*$+$7$$$H$$$&$3$H$J$s$G$7$g$&$+!#$=$l$H$be(BRubye$B$Ne(Bselecte$B$N\<he(B  
e$B$j07$$$KLdBj$,$”$k$H$$$&$3$H$J$s$G$7$g$&$+!#e(B

e$B$^$?!"e(B[ruby-core:31065]e$B$Ge(B

> I think select should notify writability when write would not block.  
> Cleary write doesn’t block on disconnected socket.

e$B$H$_$C$7$c$C$F$$$k$N$O!"!V$H$$$&5sF0$rK~$?$5$J$$e(BLinuxe$B$Ne(B  
selecte$B$O$_$+$7$$!W$H$$$&Iw$K$bFI$a$k$N$G$9$,!"$=$l$G@5$7$$$Ge(B  
e$B$9$+!#e(B

e$B$3$l$,e(BLinuxe$B$Ne(Bselecte$B$N%P%0$@$H$9$k$H!"$=$A$i$rD\>$7$F$b$i$&$Ye(B  
e$B$/%l%]!\<%H$9$k$Y$-$J$s$G$7$g$&$+!#e(B

```
                            e$B$^$D$b$He(B e$B$f$-$R$me(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:** [July 6, 2010, 4:53pm UTC](https://www.ruby-forum.com/t/bug-trunk-gnu-linux-select-hang-on-a-socket-which-tcp-state-is-closed/191149/3 "2010-07-06T16:53:50Z")

</div>

kosakie$B$G$9e(B

# e$B$$$D$bC&@~$P$+$j$G62=L$G$9e(B

> e$B$/%l%]!\<%H$9$k$Y$-$J$s$G$7$g$&$+!#e(B  
> SUSe$B$\_$k$He(B

If the writefds argument is not a null pointer, it points to an object  
of type fd\_set that on input specifies the file descriptors to be  
checked for being ready to write, and on output indicates which file  
descriptors are ready to write.

e$B$H!"e(Bready to  
writee$B$H$$$&I=8=$J$N$G!"e(BEPIPEe$B$K$J$C$A$c$&$h$&$Je(Bfde$B$Oe(Breadye$B$A$c$&$o$$!#$H$$$&$N$b2r\<a$H$7$FA4A3IT\<+A3$G$O$J$$$h$&$J!#!#!#e(B  
e$B2?$+8+Mn$H$7$F$$$k$@$m$&$+!)e(B

linuxe$B$N\<BAu8+$k$He(B

# linux/net/ipv4/tcp.c

unsigned int tcp\_poll(struct file \*file, struct socket \*sock, poll\_table  
\*wait)  
{  
(snip)  
if (!(sk-\>sk\_shutdown & SEND\_SHUTDOWN)) {  
if (sk\_stream\_wspace(sk) \>=  
sk\_stream\_min\_wspace(sk)) {  
mask |= POLLOUT | POLLWRNORM;

e$B$N$h$&$K!";W$$$C$-$j0U?^E\*$J%A%’%C%/$,$"$C$F!"$+$D$3$N%3!\<%I$,F~$C$?$N$,e(B  
Bitkeepere$BF3F~e(B(2002e$BG/!K$h$j$bA0$J$N$G7P0^$,A4A3J,$+$i$J$$$H$$$&!&!&!&e(B

e$B$H$O$$$(!"%M%C%H%o!\<%/$^$o$j$K$OA4A3\>$7$/$J$$$N$H!“L@F|5HF#$5$se(B(Linuxe$B$Ne(Bnetwork  
subsysteme$B$N%a%s%F%J!K$K2q$&M=Dj$,$”$k$N$GK:$l$F$J$+$C$?$i8+2rJ9$$$F$\_$h$&$+$H;W$$$^$9!#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:** [July 6, 2010, 5:04pm UTC](https://www.ruby-forum.com/t/bug-trunk-gnu-linux-select-hang-on-a-socket-which-tcp-state-is-closed/191149/4 "2010-07-06T17:04:58Z")

</div>

2010e$BG/e(B7e$B7ne(B6e$BF|e(B23:53 KOSAKI Motohiro  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):

> e$B$H!"e(Bready to writee$B$H$$$&I=8=$J$N$G!"e(BEPIPEe$B$K$J$C$A$c$&$h$&$Je(Bfde$B$Oe(Breadye$B$A$c$&$o$$!#$H$$$&$N$b2r\<a$H$7$FA4A3IT\<+A3$G$O$J$$$h$&$J!#!#!#e(B  
> e$B2?$+8+Mn$H$7$F$$$k$@$m$&$+!)e(B

ready to write e$B$N0UL#$O0J2\<$N$h$&$K@bL@$5$l$F$$$k$N$G!“e(B  
EPIPE e$B$@$m$&$,e(B would not block e$B$J$N$Ge(B ready  
e$B$@!”$H$$$&$3$H$G!#e(B

A descriptor shall be considered ready for writing when a call to an  
output  
function with O\_NONBLOCK clear would not block, whether or not the  
function  
would transfer data successfully.

e$B$J$_!"e(BRuby 1.9 e$BE_$K$O$=$b$=$b$J$s$Ge(B select  
e$B$7$F$$$k$N$+!"$H$$$&E@$re(B  
e$BD4$Y$J$$$H$$$1$J$$$H;W$C$F$$$^$9!#e(B

Ruby 1.8 e$BE\*$K$Oe(B select  
e$B$9$k$N$O$"$kDxEY$=$&$$$&$b$N$J$o$1$G$9$,!#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:** [August 26, 2010, 6:17am UTC](https://www.ruby-forum.com/t/bug-trunk-gnu-linux-select-hang-on-a-socket-which-tcp-state-is-closed/191149/5 "2010-08-26T06:17:22Z")

</div>

> s1.write(“a”) rescue p $!  
> e$B$=$&$$$($P!“e(B[ruby-dev:34567] e$B$H$$$&$N$b$”$j$^$7$?$,F1$8$+$J!#e(B  
> RugyKaigie$BD\>A0$N$P$?$P$?$7$F$$$k;~4|$K62=L$G$9$,!"$3$N7o$Oe(BLinuxe$BB&$rD\>$9;v$Ge(B  
> e$B9g0U$,$H$l$^$7$?!#e(Btcpe$B$Ne(Bselecte$B$bAj\<jB&$,e(Bclosee$B$7$?=j$Ge(Bselecte$B$+$i%j%?!\<%se(B  
> e$B$9$k;EMM$KJQ99$K$J$j$^$9!#e(B

e$B$3$l$GL@F|$N3+H/\<T2q5D$Ge(BRubye$B3+H/\<TMM$+$i%%3$i$l$J$$$+$H;W$&$HL$+$i4@$,e(B  
e$B$H$^$j$^$;$s!J$d$d8XD%!Ke(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:** [July 7, 2010, 1:56am UTC](https://www.ruby-forum.com/t/bug-trunk-gnu-linux-select-hang-on-a-socket-which-tcp-state-is-closed/191149/6 "2010-07-07T01:56:36Z")

</div>

e$B$^$D$b$He(B e$B$f$-$R$m$G$9e(B

In message “Re: [ruby-dev:41836] Re: [bug:trunk] GNU/Linux select hang  
on a socket which TCP state is CLOSED”  
on Wed, 7 Jul 2010 00:04:50 +0900, Tanaka A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
writes:

|e$B$J$_!"e(BRuby 1.9 e$BE_$K$O$=$b$=$b$J$s$Ge(B select e$B$7$F$$$k$N$+!"$H$$$&E@$re(B  
|e$BD4$Y$J$$$H$$$1$J$$$H;W$C$F$$$^$9!#e(B

e$B2a5n$K$O!Ve(Bselecte$B$J$/$F$b$$$$$8$c$s!W$H$$$&OC$K$O$J$C$F$^$9$M!#e(B  
e$B$H$$$&$3$H$O!"MW$9$k$Ke(B1.8e$B$N$^$^JQ99$7$F$J$$$H$$$&$@$1$N$3$He(B  
e$B$@$C$?$j$7$F!#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:** [September 25, 2010, 10:05pm UTC](https://www.ruby-forum.com/t/bug-trunk-gnu-linux-select-hang-on-a-socket-which-tcp-state-is-closed/191149/7 "2010-09-25T22:05:31Z")

</div>

e$B%A%1%C%He(B #3543 e$B$,99?7$5$l$^$7$?!#e(B (by Shyouhei U.)

e$B%9%F!\<%?%9e(B Opene$B$+$ie(BThird Party’s Issuee$B$KJQ99e(B  
ruby -v -e$B$K%;%C%He(B

## e$BK\7o$Oe(B 3rd Party’s issue e$B$G$7$?e(B [ruby-dev:42140]

[http://redmine.ruby-lang.org/issues/show/3543](http://redmine.ruby-lang.org/issues/show/3543)