[Dnsmasq-discuss] Memory usage growing over time — possibly due to logging or caching (v2.90 / OpenEmbedded kirkstone)

[Nitesh Divecha]

Hi all,

I'm using dnsmasq version 2.90 in an embedded Linux project based on the Yocto Project (kirkstone branch). The recipe in use is from the OpenEmbedded meta-networking layer: https://layers.openembedded.org/layerindex/recipe/304520/

I've observed that dnsmasq memory usage steadily increases over time, even under light DNS query loads. For example:

- On boot: ~1.1 MB
- After 1 hour: ~3.3 MB
- After ~14 hours: ~15.3 MB

Relevant configuration (via NetworkManager):
# cat /etc/NetworkManager/dnsmasq.d/dnsmasq-dns.conf 
no-negcache
stop-dns-rebind

server=8.8.8.8
server=1.1.1.1

all-servers

log-queries
log-facility=/var/log/dnsmasq.log


I noticed that the `/var/log/dnsmasq.log` file grows continuously (currently ~15M), and suspect that this may be contributing to memory growth — either due to internal buffering or cumulative logging state.

My questions:
1. Is this memory growth expected when `log-queries` is enabled with `log-facility`?
2. Does `dnsmasq` buffer log output internally, or are there known issues with memory not being reclaimed after prolonged logging?
3. Are there recommended best practices for logging in long-running embedded environments to avoid this kind of memory usage?

Any suggestions or insights would be greatly appreciated.

Thanks in advance,  

Cheers,
Nitesh