[Dnsmasq-discuss] Dnsmasq server enabled IPv6 RA error: kernel: dnsmasq[26991]: segfault at 0 ip 0000003b12080e1e sp 00007fff17a4d2f8 error 6 in libc-2.12.so[3b12000000+18a000]

Simon Kelley simon at thekelleys.org.uk
Fri Jan 10 17:19:08 GMT 2014


On 10/01/14 10:45, Da Zhao Y Yu wrote:
> Hi All,
>
> I encountered some problems when use dnsmasq to support IPv6 router
> advertisement
>
> I want to use IPv6 ra-only mode in my openstack environment.
>
> When I run the following dnsmasq command:
>
> /usr/sbin/dnsmasq --no-hosts --no-resolv --strict-order
> --bind-interfaces --interface=tapbc4dfa1a-d1 --except-interface=lo
> --pid-file=/var/lib/neutro/dhcp/5abfc7bd-c5dd-47f9-aeb5-757534881dfb/pid
> --dhcp-hostsfile=/var/lib/neutron/dhcp/5abfc7bd-c5dd-47f9-aeb5-757534881dfb/host
> --dhcp-optsfile=/var/lib/neutron/dhcp/5abc7bd-c5dd-47f9-aeb5-757534881dfb/opts
> --leasefile-ro --dhcp-range=set:tag0,2001:2011::,ra-only,86400s
> --dhcp-lease-max=16777216 --conf-file= --domain=openstacklocal
>
>  From /var/log/messages, I just got the following message:
>
> Jan 10 04:06:57 localhost dnsmasq[26991]: started, version 2.64
> cachesize 150
> Jan 10 04:06:57 localhost dnsmasq[26991]: compile time options: IPv6
> GNU-getopt DBus no-i18n no-IDN DHCP DHCPv6 no-Lua TFTP no-conntrack
> Jan 10 04:06:57 localhost dnsmasq[26991]: warning: no upstream servers
> configured
> Jan 10 04:06:57 localhost *dnsmasq-dhcp[26991]: IPv6 router
> advertisement enabled*
> Jan 10 04:06:57 localhost* kernel: dnsmasq[26991]: segfault at 0 ip
> 0000003b12080e1e sp 00007fff17a4d2f8 error 6 in
> libc-2.12.so[3b12000000+18a000]*
>
> Who can give me some suggestion about it?
>
> Also when I set the dhcp-modes as static, it is OK,
>

Would it be possible to try doing the same thing with dnsmasq-2.68, just 
to save us chasing bugs which are already fixed?

If you see the same problem in 2.68, then doing the following would be 
useful

1) Build dnsmasq with debugging symbols

cd /path/to/dnsmasq-2.68; make clean; make CFLAGS=-g

2) Run dnsmasq under gdb

gdb /path/to/dnsmasq-2.68/src/dnsmasq

3) Start dnsmasq with command line options you use, but add -d

run -d --no-hosts --no-resolv, .............

4) When the segfault occurs, run print a backtrace:

bt

5) Send the output from the bt command to me and/or/ the list.


Cheers,

Simon.




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