On 11/09/14 11:59, Petr Spacek wrote:

I was fighting with random crashes for couple of days ... and discovered that run_exclusive_enter()/isc_task_beginexclusive() usage was completely incorrect and didn't actually lock anything.

This series of patches reworks internal locking (and related event system) to work around limitations of isc_task_beginexclusive() mechanism.

It would be better to get rid of isc_task_beginexclusive() completely but IMHO it is not possible because of BIND's dns_view*() functions have to be guarded with it.

Testing is going to be interesting because we are speaking about race conditions.

I used ~ 100 DNS zones, each zone had ~ 100 random domain names inside with random A/AAAA/TXT RRs. My LDIF is here:

I was able to randomly reproduce various crashes when BIND was running with more threads than usually.

You can try to run BIND with this command (as root) and play games with -n parameter:
$ export KRB5_KTNAME="/etc/named.keytab"
$ named -4 -g -u named -m record -n 10

Please test also the case where BIND receives SIGINT during start-up. It is possible to run BIND with commands above and wait for message:
11-Sep-2014 11:54:58.092 running

At this point send SIGINT (CTRL+C) to BIND and see what happens. It could crash or deadlock.

It is necessary to send the signal before BIND prints this message:
11-Sep-2014 11:55:11.707 zone z1.test/IN: loaded serial 1410429304

Let me know if you need any assistance.

I need your assistance, I haven't been able to reproduce it.


Martin Basti

Freeipa-devel mailing list

Reply via email to