Re: [uml-devel] Thread (NPTL?) support, 2.6.20-rc5-git3, x86_64, reproducible segmentation fault and possible culprit

[William Stearns <wstearns@pobox.com>]

Good afternoon, all,

On Sun, 28 Jan 2007, William Stearns wrote:

> 	Vince Berk pointed out what appears to be a thread issue with uml. 
> The "host" command, part of the bind-utils package, uses threads and crashes 
> when asked to do anything more complex than show its help screen:
>
> -bash-3.1# rpm -q bind-libs bind-utils
> bind-libs-9.3.3-0.1.rc3.fc6
> bind-utils-9.3.3-0.1.rc3.fc6
> -bash-3.1# host www.google.com.
> Segmentation fault
>
> 	(strace below)
>
> 	I rebuilt the "bind" rpm (which creates bind-utils and bind-libs) 
> with a one-line change to the spec file, specifically to the configure 
> command:
>
> [wstearns@spamgate SPECS]$ diff -bud bind.spec.orig bind.spec
> --- bind.spec.orig      2006-12-06 09:55:51.000000000 -0500
> +++ bind.spec   2007-01-28 13:13:54.000000000 -0500
> @@ -320,7 +320,7 @@
> %configure \
>        --with-libtool \
>        --localstatedir=/var \
> -       --enable-threads \
> +       --disable-threads \
>        --enable-ipv6 \
>        --with-pic \
>        --with-openssl=/usr \
>
> 	The new packages work just fine inside uml:
>
> -bash-3.1# rpm -e bind-libs bind-utils
> -bash-3.1# rpm -Uvh 
> /home/wstearns/rpm/RPMS/x86_64/bind-libs-9.3.3-0.1.rc3.x86_64.rpm 
> /home/wstearns/rpm/RPMS/x86_64/bind-utils-9.3.3-0.1.rc3.x86_64.rpm
> Preparing...                ###########################################
>   1:bind-libs              ########################################### [
>   2:bind-utils             ########################################### 
> -bash-3.1# host www.google.com.
> www.google.com is an alias for www.l.google.com.
> www.l.google.com has address 64.233.161.99
> www.l.google.com has address 64.233.161.104
> www.l.google.com has address 64.233.161.147
>
> 	The problem is completely reproducible; the root filesystem and 
> kernel at http://ford.stearns.org/uml/ give a crash every time you actually 
> try to look something up with "host".
> 	Should I be talking to the glibc folks about this?

 	As a side note, if I try to bypass thread support per the 
instructions at http://dag.wieers.com/howto/compatibility/ , I get a 
different error (following is with stock "host"):

-bash-3.1# LD_ASSUME_KERNEL=2.4.19 host www.google.com
host: error while loading shared libraries: libnsl.so.1: cannot open 
shared object file: No such file or directory

-bash-3.1# export LD_ASSUME_KERNEL=2.4.19
-bash-3.1# strace -f host www.google.com.
strace: error while loading shared libraries: libc.so.6: cannot open 
shared object file: No such file or directory

 	Both exist:

$ locate libc.so.6
/lib/libc.so.6
/lib/i686/nosegneg/libc.so.6
/lib64/libc.so.6
$ ls -al `locate libc.so.6`
lrwxrwxrwx 1 root root 11 Jan 25 21:20 /lib/i686/nosegneg/libc.so.6 -> 
libc-2.5.so
lrwxrwxrwx 1 root root 11 Jan 25 21:20 /lib/libc.so.6 -> libc-2.5.so
lrwxrwxrwx 1 root root 11 Jan 25 21:20 /lib64/libc.so.6 -> libc-2.5.so
$ ls -al `locate libc-2.5.so`
-rwxr-xr-x 1 root root 1589880 Jan  5 12:39 /lib/i686/nosegneg/libc-2.5.so
-rwxr-xr-x 1 root root 1573504 Jan  5 12:39 /lib/libc-2.5.so
-rwxr-xr-x 1 root root 1672928 Jan  5 12:25 /lib64/libc-2.5.so

 	Cheers,
 	- Bill

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--------------------------------------------------------------------------
William Stearns (wstearns@pobox.com).  Mason, Buildkernel, freedups, p0f,
rsync-backup, ssh-keyinstall, dns-check, more at:   http://www.stearns.org
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