Greg, What other awesome stuff do you have on the top of your head? This makes 
sense as it’s running on EC2 @AWS (I.e. poor source of randomness on VM’s).

And thanks to Grant for the haveged suggestion.  Initial tests with haveged 
running seem to be positive.

I’ll report back here if the problem continues.

Thanks so much for your help!


From: Greg Choules <gregchoules+bindus...@googlemail.com>
Date: Monday, August 1, 2022 at 6:21 PM
To: White, Peter <pwh...@penguinrandomhouse.com>
Cc: bind-users@lists.isc.org <bind-users@lists.isc.org>
Subject: Re: Bind 9.11/RHEL7 Server Freezes FUTEX_WAKE_PRIVATE
CAUTION: This email originated from outside of Penguin Random House. Please be 
extra cautious when opening file attachments or clicking on links.

Hi Peter.
Off the top of my head, could it be this?

random-device

The source of entropy to be used by the server. Entropy is primarily needed for 
DNSSEC operations, such as TKEY transactions and dynamic update of signed 
zones. This options specifies the device (or file) from which to read entropy. 
If this is a file, operations re- quiring entropy will fail when the file has 
been exhausted. If not specified, the default value is /dev/random (or 
equivalent) when present, and none otherwise. The random- device option takes 
effect during the initial configuration load at server startup time and is 
ignored on subsequent reloads.

BIND will need a good source of randomness for crypto operations.

Cheers, Greg

On Mon, 1 Aug 2022 at 23:08, White, Peter 
<pwh...@penguinrandomhouse.com<mailto:pwh...@penguinrandomhouse.com>> wrote:

I’m running BIND 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.9 (Extended Support 
Version) on RHEL 7 in a chroot jail.

As of late, at times running some rndc commands are causing my server to lock 
up. It’s usually an “rndc addzone” that triggers the issue. I’ll also mention 
that I have recently started signing some domains with DNSSEC, so I suspect it 
may be somehow related.

Here is an example of a command that frequently triggers my issue, although it 
doesn’t trigger it every time.

rndc addzone '"example.com<http://example.com>" in external {type master; file 
"dnssec/example.com<http://example.com>";key-directory "keys"; auto-dnssec 
maintain; inline-signing yes;};'

During these times, named will not respond to any rndc commands, nothing is 
logged to the bind logs (I’m running trace level 3 ), and will not answer 
queries. Everything seems just frozen in time. Waiting for a period of time, 
varying from a few seconds to many minutes, the server picks back up again and 
operates normally. The following are my observations to this point.

CPU and memory show as being fine.


top - 17:57:37 up 33 min,  3 users,  load average: 0.00, 0.01, 0.05

Tasks: 125 total,   2 running, 123 sleeping,   0 stopped,   0 zombie

%Cpu(s):  0.2 us,  0.3 sy,  0.0 ni, 98.5 id,  0.0 wa,  0.0 hi,  0.0 si,  1.0 s

KiB Mem :  1842956 total,   439452 free,   665760 used,   737744 buff/cache

KiB Swap:  8384508 total,  8384508 free,        0 used.  1013652 avail Mem

Strace shows the following over and over again.


strace -p 1156 -f



[pid  1159] futex(0x7fc1c15a307c, 
FUTEX_WAIT_BITSET_PRIVATE|FUTEX_CLOCK_REALTIME, 16657, {tv_sec=1659390139, 
tv_nsec=255860000}, 0xffffffff) = -1 ETIMEDOUT (Connection timed out)


Any pointers here would be greatly appreciated. I’m about at my wits end with 
this one, and rebuilding this server on a newer build of RHEL or recompiling 
BIND is not a journey that I would like to take at the moment.
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