On Fri, Jul 29, 2022 at 10:23:15AM -0300, Athos Ribeiro wrote:
> https://pad.lv/1980146 - (New) [dnsmasq] - dnsmasq often
> using 100% of CPU
> I tagged this as server-triage-discuss. Multiple users confirmed the bug,
> but
> finding a reliable reproducer may be tricky. Instead of adding this to the
> backlog, I am wondering if we have a clear path for this sort of
> (performance
> issues) bug.
I googled on "dnsmasq is caught in a loop after every dns request,
resulting in 100% CPU". In reading the suggested links (listed below),
here's some additional info that could be asked for, that might help
shed light:
generally:
* dpkg --get-selections | cut -f 1
* /etc/resolv.conf
* /etc/NetworkManager/NetworkManager.conf
* /etc/dnsmasq.conf
* /run/dnsmasq/resolv.conf
* /var/run/dhcpd.leases (or /run/dhcpd.leases?)
when the system is at 100%:
* ps aux
- Is logrotate running? (Or some other 'heavy' process?)
* journalctl -f
- Any mention of "maximum number of concurrent dns queries reached"?
Possible tool to help reproduce
* https://github.com/jedisct1/dnsblast
Unfortunately "Randomly 100% CPU" isn't ever really descriptive enough
to be actionable as a bug. Could it just be a misconfiguration in the
dns settings? This type of issue may be more effective to tackle first
as a tech support request through other channels, and if it can be
boiled down to a specific, reproducible problem (with a test case) then
handle as a proper bug.
The 'me-too' comment #3 could likely be having an unrelated problem and
should be reported as a different bug (with full logs and config)
References:
*
https://discourse.pi-hole.net/t/dnsmasq-consumes-100-cpu-after-a-few-minutes/10367
*
https://unix.stackexchange.com/questions/417645/dnsmasq-systemd-causing-intermittent-cpu-spikes
*
https://unix.stackexchange.com/questions/304050/how-to-avoid-conflicts-between-dnsmasq-and-systemd-resolved
*
https://community.ui.com/questions/dnsmasq-process-causing-high-CPU-usage-on-USG-3/a3ee0c2a-8ebf-4089-9347-4cfb95d9d520#answer/1c27c8ba-bd6b-4c28-a2ad-e5ed51acc3fa
* https://github.com/openwrt/packages/issues/11410
Bryce
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