[Dnsmasq-discuss] dnsmasq rc5 segfault

[Carlos Carvalho]

Simon Kelley (simon at thekelleys.org.uk) wrote on 11 July 2008 19:40:
 >Carlos Carvalho wrote:
 >> Today dnsmasq died. It was the first time since I use it :-(
 >> 
 >> In its log there's no sign of problems. The last entry is for a
 >> DHCPNAK; it's the only such record with 2.43. The kernel log says
 >> 
 >> Jul 11 14:27:38 hoggar dnsmasq[11797]: segfault at 10 ip 08061e91 sp bfffe770 error 4 in dnsmasq[8048000+22000]
 >> 
 >> The kernel is compiled with several PAX protections, in particular
 >> non-executable pages.
 >> 
 >> Any ideas on how to debug this? All I can imagine demand a significant
 >> amount of work here :-(
 >> 
 >
 >Best bet is to be ready to catch the next one.
 >
 >1) rebuild dnsmasq with
 >
 >make CFLAGS=-g

Done.

 >2) enable coredumps and move to a directory where they can be written
 >
 >ulimit -c unlimited

Done.

 >3) run dnsmasq in the foreground
 >
 >dnsmasq -d

D... ops, sorry, I can't run a segfaulting program as root in the
central server of the department...

I ran it normally and sent it a quit signal but it didn't produce a
core; it works for other programs. I changed the chdir / in dnsmasq.c
to "/tmp" to no avail (it does the chdir). Why doesn't it produce a core?