glibc and valgrind memcheck errors (cgi segmentation fault) with nagios 3.06 on Redhat 4.7 x86

[Justin Amburn]

Thanks for the reply Andreas.

No updates to glibc until the problem started happening. Then, the
kernel and and glibc were brought up to date with Redhat's most recent
packages to address the issue. Currently using glibc-2.3.4-2.41.el4_7.1.
Also, localtime is up to date. I noticed, however, that since omitting
the Service Check for the event viewer (which causes the unexpected
newline in status.dat) we have not had the issue. Normally something is
logged to event viewer on a given Windows server at 3am and then
immediately we see sporadic and eventual complete series of seg faults
when accessing cgi's. The only remediation was to roll back to a time
where these events did not exist. I'm pretty sure that there is a strong
correlation between them. If so, then something logged to event viwer
and passed back to nagios via plugin might disrupt cgi display.

To reproduce, grab the plugin called Eventlog.exe (size is 20,480 bytes)
from nagiosexchange.com and try to get Event viewer to log something
with "\\" like a UNC for example and pass it back to nagios (or is there
some other way to artificially put it into status.dat?) 

Regards,

Justin Amburn

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-----Original Message-----
From: Andreas Ericsson [mailto:ae at op5.se] 
Sent: Monday, March 23, 2009 6:14 AM
To: Nagios Developers List
Cc: Justin Amburn
Subject: Re: [Nagios-devel] glibc and valgrind memcheck errors (cgi
segmentation fault) with nagios 3.06 on Redhat 4.7 x86

Justin Amburn wrote:
> Here is an strace of the segmentation fault, if this is of any use to
> anyone:
> 

> open("/etc/localtime", O_RDONLY)        = 4
> fstat64(4, {st_mode=S_IFREG|0644, st_size=1017, ...}) = 0
> fstat64(4, {st_mode=S_IFREG|0644, st_size=1017, ...}) = 0
> mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
> 0) = 0xb7a88000
> read(4,
> "TZif\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\4\0\0\0\4\0\0\0\0"...,
4096)
> = 1017
> close(4)                                = 0
> munmap(0xb7a88000, 4096)                = 0
> --- SIGSEGV (Segmentation fault) @ 0 (0) ---
> +++ killed by SIGSEGV +++
> 

Looks like glibc is bugging out when it's reading timezones for some
reason.
Have you upgraded glibc recently?

-- 
Andreas Ericsson                   andreas.ericsson at op5.se
OP5 AB                             www.op5.se
Tel: +46 8-230225                  Fax: +46 8-230231

Considering the successes of the wars on alcohol, poverty, drugs and
terror, I think we should give some serious thought to declaring war
on peace.

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