On a hypervisor host I have a scripts which uses iptables to setup all the firewall rules for allowing and passing connections across various fabrics and VMs.
At the top of the script, I flush the tables:
iptables -t filter -F
Recently, this has been causing the kernel to hang and start throwing abrt messages:
Message from syslogd@node09 at July 5 14:09:52 ...
kernel:NMI watchdog: BUG: soft lockup - CPU#10 stuck for 23s! [iptables:23172]
This message is printed multiple times with different core numbers, and only appears after seemingly minutes, not 23s.
Why would iptables be causing the kernel to hang like this?
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