Maintained by: NLnet Labs

[Unbound-users] Unbound 1.4.18 crashes under high query load

Janne Snabb
Fri Oct 26 20:22:54 CEST 2012

On 2012-10-25 13:56, W.C.A. Wijngaards wrote:

> This is the same bug with openssl-locking.  The newer openssl
> requires the locking, where the previous versions did not need
> locking for the functions that unbound uses.  This is causing the
> double-free and other failure that you noted.  It is fixed in svn
> trunk of unbound.

Thank you. The backtrace looked somewhat different and I thought it
got triggered with num-threads == 1 so I thought it would be a
different issue.

> The crash with num-threads 1 is odd, can you reproduce that with
> the svn-trunk version?

I now believe that this must have been a mistake on my part. I can not
reproduce this with num-threads == 1 any more. I must have originally
forgotten to restart Unbound after changing num-threads. Sorry about that.

I am happy to confirm that the patch at the following URL seems to
have corrected the problem:

I will continue testing over the weekend to make sure the problem is
gone. I have applied the patch against Unbound 1.4.18 and 1.4.16 (the
latter with minor tweaks) and both seem to be running fine so far.

I have updated my Ubuntu bug report accordingly:

Best Regards and Thank You,
Janne Snabb / EPIPE Communications
snabb at -