Bind 9.11/RHEL7 Server Freezes FUTEX_WAKE_PRIVATE

White, Peter pwhite at penguinrandomhouse.com
Mon Aug 1 22:08:15 UTC 2022


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" in external {type master; file "dnssec/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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