Significant memory usage

[Philip Prindeville]

Hi,

I’ve been running 9.20.7 on OpenWRT for over a year without issues.  Yesterday, however, it died because of OOM (out-of-memory) kill from the kernel.

I use it with isc-dhcp service for IPv4, and do split horizon for internal domains.

What I’ve noticed is that at startup I’m using about 33K pages as the VSZ (per top on x86_64 hardware).

Within a minute, however, that’s doubled to 72600+ pages.  More than double.

This is a small network with 1 domain (plus two rDNS domains), and not more than 400 RR’s total.

If I do an “rndc flush” is drops about 3000 pages, but slowly starts creeping up again.

I updated to 9.20.8 a few minutes ago but I’m still seeing the same issue.

root at OpenWrt:~# named -V
BIND 9.20.8 (Stable Release) <id:>
running on Linux x86_64 6.6.41 #0 SMP Sat Jul 27 03:38:57 2024
built by make with  '--target=x86_64-openwrt-linux' '--host=x86_64-openwrt-linux' '--build=x86_64-pc-linux-gnu' '--disable-dependency-tracking' '--program-prefix=' '--program-suffix=' '--prefix=/usr' '--exec-prefix=/usr' '--bindir=/usr/bin' '--sbindir=/usr/sbin' '--libexecdir=/usr/lib' '--sysconfdir=/etc' '--datadir=/usr/share' '--localstatedir=/var' '--mandir=/usr/man' '--infodir=/usr/info' '--disable-geoip' '--with-openssl=/home/philipp/lede/staging_dir/target-x86_64_musl/usr' '--without-lmdb' '--without-readline' '--sysconfdir=/etc/bind' '--with-json-c=no' '--with-libxml2=no' '--enable-doh' '--without-gssapi' 'build_alias=x86_64-pc-linux-gnu' 'host_alias=x86_64-openwrt-linux' 'target_alias=x86_64-openwrt-linux' 'CC=x86_64-openwrt-linux-musl-gcc' 'CFLAGS=-Os -pipe -g3 -fno-caller-saves -fno-plt -fhonour-copts -fmacro-prefix-map=/home/philipp/lede/build_dir/target-x86_64_musl/bind-9.20.8=bind-9.20.8 -Wformat -Werror=format-security -fstack-protector -D_FORTIFY_SOURCE=1 -Wl,-z,now -Wl,-z,relro   ' 'LDFLAGS=-L/home/philipp/lede/staging_dir/toolchain-x86_64_gcc-14.2.0_musl/usr/lib -L/home/philipp/lede/staging_dir/toolchain-x86_64_gcc-14.2.0_musl/lib -fuse-ld=bfd -znow -zrelro   -Wl,--gc-sections,--as-needed ' 'CPPFLAGS=-I/home/philipp/lede/staging_dir/toolchain-x86_64_gcc-14.2.0_musl/usr/include -I/home/philipp/lede/staging_dir/toolchain-x86_64_gcc-14.2.0_musl/include -I/home/philipp/lede/staging_dir/toolchain-x86_64_gcc-14.2.0_musl/include/fortify   ' 'PKG_CONFIG=/home/philipp/lede/staging_dir/host/bin/pkg-config' 'PKG_CONFIG_PATH=/home/philipp/lede/staging_dir/target-x86_64_musl/usr/lib/pkgconfig:/home/philipp/lede/staging_dir/target-x86_64_musl/usr/share/pkgconfig' 'PKG_CONFIG_LIBDIR=/home/philipp/lede/staging_dir/target-x86_64_musl/usr/lib/pkgconfig:/home/philipp/lede/staging_dir/target-x86_64_musl/usr/share/pkgconfig'
compiled by GCC 14.2.0
compiled with OpenSSL version: OpenSSL 3.0.16 11 Feb 2025
linked to OpenSSL version: OpenSSL 3.0.14 4 Jun 2024
compiled with libuv version: 1.48.0
linked to libuv version: 1.48.0
compiled with liburcu version: 0.15.2
compiled with libnghttp2 version: 1.63.0
linked to libnghttp2 version: 1.62.1
compiled with zlib version: 1.3.1
linked to zlib version: 1.3.1
threads support is enabled
DNSSEC algorithms: RSASHA1 NSEC3RSASHA1 RSASHA256 RSASHA512 ECDSAP256SHA256 ECDSAP384SHA384 ED25519 ED448
DS algorithms: SHA-1 SHA-256 SHA-384
HMAC algorithms: HMAC-MD5 HMAC-SHA1 HMAC-SHA224 HMAC-SHA256 HMAC-SHA384 HMAC-SHA512
TKEY mode 2 support (Diffie-Hellman): no
TKEY mode 3 support (GSS-API): no

default paths:
  named configuration:  /etc/bind/named.conf
  rndc configuration:   /etc/bind/rndc.conf
  nsupdate session key: /var/run/named/session.key
  named PID file:       /var/run/named/named.pid
root at OpenWrt:~# 

What would explain the sudden increase in memory usage when the environment has been relatively static?

Thanks,

-Philip