[Dnsmasq-discuss] segfault - Re: No dnsmasq after starting openVPN?!

Jan 'RedBully' Seiffert redbully at cc.hs-owl.de
Sun Jun 6 17:48:59 BST 2010


Arno Wald schrieb:
> On 06.06.2010 12:06, Arno Wald wrote:
>> I did not enter anything but just started openvpn. The dnsmasq process
>> did not disappear. In gdb I entered "c" and after this "bt" and "q":
> 
> I did the same with a self compiled dnsmasq package following this guide
> http://jameswestby.net/tips/tips/compiling-debian-package-for-debug.html
> 
> and the result is this:
> 
> (gdb) c
> Continuing.
> 
> Program received signal SIGSEGV, Segmentation fault.
> 0x08067156 in netlink_multicast () at netlink.c:249
> 249           for (h = (struct nlmsghdr *)iov.iov_base; NLMSG_OK(h, 
> (size_t)len); h = NLMSG_NEXT(h, len))
> (gdb) bt
> #0  0x08067156 in netlink_multicast () at netlink.c:249
> #1  0x0805cea5 in main (argc=9, argv=0xbfff3554) at dnsmasq.c:662
> 
> 
> Does this help?
> 

I'm not Simon, but from a quick look:
Kind of...
Looks like when openvpn creates it's interfaces (or route or whatever), the
netlink message send to dnsmasq to inform dnsmasq of the new interface crashes
dnsmasq.
But i still do not grok that code there...
Opaque binary structures *sigh*, some printf would be nice.

Can you try again with gdb typing in:
bt full
info frame
info registers
disass $pc
list

Hmmm, and maybe smuggle a "-g3" into the CFLAGS used to compile dnsmasq would be
nice.

> Greetings,
> Arno
> 

Thanks for your time testing this

Greetings
	Jan

-- 
"If you give someone a program, you will frustrate them for a day;
if you teach them how to program, you will frustrate them for a lifetime."
	— Anonymous



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