Bug#495007: libc6: getaddrinfo_a causes SetFault in amd64 version

[Matthew Von-Maszewski <matthew@thehive.com>]

Aurelien,

I can truly appreciate your hesitation with this bug report.  I can  
see how stupid this must look from your view point.

May I suggest this:

- verify whether or not debian/linuxthreads/sysdeps/pthread/gai_misc.h  
really contributes to a build.  Simply put garbage characters in the  
file and run a build.  If our analysis is correct, your build will  
fail.  We saw the file being used.

- try the test program contributed by Jon.  Try it even if you have a  
32 bit box.  The size of stack overflow is large enough that I suspect  
the amd64 is not really a key issue.

- we have a highly reproducible case.  Ask for any and all supporting  
data.  I can provide it:  register snap shots by frame, disassembly  
step through/to the crash point, etc.  I can be a resource.

Matthew



On Aug 13, 2008, at 9:10 PM, Aurelien Jarno wrote:

> On Wed, Aug 13, 2008 at 08:23:31PM -0400, Matthew Von-Maszewski wrote:
> > Aurelien,
> >
> > I doubt "linuxthreads" is anything but an old directory being reused.
> > The file gai_misc.h appears in two places.  The one I mention below  
> > in
> > the debian and another in the ./resolve directory.  The debian tree
> > version appears to be someone's attempt at optimizing memory usage on
> > the secondary thread.  The debian version overrides the libc/resolve
> > version. The secondary thread is created by a conventional pthreads
> > call (again unrelated to "linuxthreads").
>
> I don't understand why you are speaking about a debian version, debian
> does not patch this file, so there is nothing about optimizing memory
> usage.
>
> > The reduced stack size is now being pounded by what appears to be a
> > ton of relatively new getaddrinfo code.  __res_vinit() has a large
> > buffer it takes out of the stack.  It makes sense that the stack is
> > now to small.
> >
> > I ask that you give the bug serious consideration as written.  I
>
> I haven't found yet a time to get a closer look, but your analysis  
> seems
> to be wrong given that:
> - we are not using the linuxthreads anymore
> - we do not change gai_misc.h
>
> I'll have a closer look tomorrow.
>
> --
>  .''`.  Aurelien Jarno	            | GPG: 1024D/F1BCDB73
> : :' :  Debian developer           | Electrical Engineer
> `. `'   aurel32@debian.org         | aurelien@aurel32.net
>   `-    people.debian.org/~aurel32 | www.aurel32.net