[teqc] "glibc" problem

Andrew Chan andrewchan at jdbarnes.com
Mon Apr 25 06:45:16 MDT 2005


We are using the static teqc version on Fedora Core 3 with a workaround 
by setting the system  environment variable MALLOC_CHECK_ to "0".

 From the malloc man page:

       Recent versions of Linux libc (later than 5.4.23) and GNU  libc  
(2.x)
       include a malloc implementation which is tunable via environment 
vari-
       ables.  When MALLOC_CHECK_ is set, a special (less  efficient)  
imple-
       mentation  is  used  which  is  designed to be tolerant against 
simple
       errors, such as double calls of free()  with  the  same  
argument,  or
       overruns  of a single byte (off-by-one bugs).  Not all such 
errors can
       be protected against, however, and memory leaks can result.   If  
MAL-
       LOC_CHECK_  is  set  to  0,  any  detected heap corruption is 
silently
       ignored; if set to 1, a diagnostic is printed on stderr; if set 
to  2,
       abort() is called immediately.  This can be useful because 
otherwise a
       crash may happen much later, and the true cause  for  the  
problem  is
       then very hard to track down.

Andrew

Lou Estey wrote:

> The following was sent to Geoff Blewitt, sans the attachments.
>
> --lou
>
> -------- Original Message --------
> Subject: Re: [teqc] "glibc" problem
> Date: Sun, 24 Apr 2005 13:31:42 -0600 (MDT)
> From: Lou Estey <lou at unavco.org>
> To: gblewitt at unr.edu
> CC: Lou Estey <lou at unavco.org>
>
> hi Geoff,
>
>> I have the 2002 dynamic build of teqc running just fine on Fedora 2 
>> and 3 on various Dell machines, except on (only) two of my machines I 
>> sometimes get the following error message:
>>
>> *** glibc detected *** double free or corruption: 0x08112420 ***
>> Abort (core dumped)
>>
>> The static build doesn't work at all (a previously known problem).
>> (I haven't tried the latest releases as I've been happy with the 
>> stability so far, but will upgrade if that would fix the problem).
>>
>> Anyone come across this problem and has a fix for it?  I don't really 
>> know anything about "glibc" and I'm guessing maybe there's a 
>> configuration file for glib somewhere that I can fix?
>
>
> "glibc" is the GNU library for most of the standard C functions,
> like memory allocation.  There is no configuration file that I
> know about.  This sounds related to the seeminly random memory
> deallocation problem reported in the Linux x86 builds of teqc
> for years.  (No known solution.)
>
> Best bet is to try the current development version of teqc for
> Linux x86 (attached)
>
> teqc_Lx86d.tar.Z: dynamically-linked
> teqc_Lx86s.tar.Z: statically-linked
>
> and see http://ls.unavco.org/pipermail/teqc/2005/000093.html
>
> Let me know whether or not whether either of these work out for you.
>
> cheers,
> --lou
>
> _______________________________________________
> teqc mailing list
> teqc at ls.unavco.org
> http://ls.unavco.org/mailman/listinfo/teqc


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