httpd-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Doug Bloebaum <bla...@iii.co.uk>
Subject Re: Segmentation faults :(
Date Thu, 08 Oct 1998 08:45:23 GMT
Phew, finally got a core dump and this stack trace:

#0  0x52e50 in ap_proxy_send_fb ()
#1  0x514c4 in ap_proxy_http_handler ()
#2  0x466d0 in mod_perl_set_opmask ()
#3  0x899ac in ap_invoke_handler ()
#4  0xa4010 in ap_some_auth_required ()
#5  0xa4090 in ap_process_request ()
#6  0x98f8c in ap_child_terminate ()
#7  0x992e8 in ap_child_terminate ()
#8  0x99828 in ap_child_terminate ()
#9  0x99fb4 in ap_child_terminate ()
#10 0x9a818 in main ()

mod_perl certainly appears to be involved...

By the way, to potentially save someone else the pain of figuring out
how to get a core file from a setuid Apache httpd process in Solaris,
without knowing which httpd child might be the one to die, here's what
I ended up doing:

# for pid in `ps -eaf | fgrep httpd_1.3.3 | cut -d' ' -f4`
> do
>   truss -f -l -t\!all -S SIGSEGV -p $pid 2>&1 | egrep SIGSEGV &
> done

The undocumented '-S' flag to truss will halt the process in place
upon receipt of a given signal (SIGSEGV in this case.)  At this point
I used:

# gcore <PID>

to generate a core file, then

# gdb httpd_1.3.3 core.<PID>
(gdb) where

to get the backtrace.

The following Usenet thread was a big help:

http://www.dejanews.com/=zzz_maf/dnquery.xp?search=thread&svcclass=dnserver&recnum=%3c6iueei$fjt@engnews1.Eng.Sun.COM%3e%231/1

Michael Smith writes:
 > Ralf S. Engelschall wrote:
 > 
 > > In article <361B7975.F2B954AC@iii.co.uk> you wrote:
 > >
 > > > Probably not a show-stopper but I'm seeing segmentation faults under
 > > > 1.3.3 (also get them under 1.3.2); which look like this in the error
 > > > log:
 > >
 > > > [Wed Oct  7 16:20:52 1998] [notice] httpd: child pid 21631 exit signal
 > > > Segmentation Fault (11)
 > > > [Wed Oct  7 16:21:43 1998] [notice] httpd: child pid 21623 exit signal
 > > > Segmentation Fault (11)
 > > >[...]
 > > > Anyone else seen something similar?
 > >
 > > ARGL! Good that you say something. I'm also currently debugging (mod_ssl's
 > > gcache stuff) 1.3.3 and get a similar "child exit" problem. I thought it was a
 > > gcache bug recently introduced, but after inspecting the recent code changes I
 > > now thing it's more a bug in Apache. I'm still debugging, so cannot say more
 > > than my problem is a similar one with 1.3.3.... more details coming when I
 > > know more.
 > 
 > Yeh, we're trying to get some more information but haven't been able to persuade
 > the solaris kernel to let 'nobody' dump core.  We're not using mod_ssl so it's
 > not an issue with that module for us!  Unfortunately we only see it on our "live"
 > system, where it appears every minute or so (= about every 500 hits).
 > 
 > More details coming when we know more!
 > 

-- 
Doug Bloebaum                             interactive investor
Systems Engineer                          105-109 Strand, London WC2R 0AB
blabes@iii.co.uk                          http://www.iii.co.uk

Mime
View raw message