Specifying "max-cache-size default;" causes core-dump
Doug Freed
dwfreed at isc.org
Sun Sep 14 04:20:01 UTC 2025
On 9/13/25 21:32, Nick Tait via bind-users wrote:
> Hi list.
>
> I've tried to raise a new issue for BIND on https://gitlab.isc.org/isc-
> projects/bind9/-/issues but unfortunately when I click "Create issue",
> it pops up a banner saying: /Your issue has been recognized as spam.
> Please, change the content or solve the reCAPTCHA to proceed./
>
> ...And no reCAPTCHA code is displayed.
>
> So I hope it's OK if I report the issue to this list instead?
>
> Thanks,
>
> Nick.
>
> ------------------------------------------------------------------------
>
> */Specifying "max-cache-size default;" causes core-dump/*
>
> *### Summary*
>
> Specifying `max-cache-size default;` in the configuration causes an
> assertion failure.
>
> *### BIND version affected*
>
> The BIND versions that I've tested are 9.20.4 (included with Linux
> distro) and 9.20.14 (i.e. downloaded and compiled latest version).
>
> ```
> BIND 9.20.14-dev (Stable Release) <id:1cbd8b8>
> running on Linux x86_64 6.14.0-29-generic #29-Ubuntu SMP PREEMPT_DYNAMIC Thu Aug 7 18:32:38 UTC 2025
> built by make with default
> compiled by GCC 14.2.0
> compiled with OpenSSL version: OpenSSL 3.4.1 11 Feb 2025
> linked to OpenSSL version: OpenSSL 3.4.1 11 Feb 2025
> compiled with libuv version: 1.50.0
> linked to libuv version: 1.50.0
> compiled with liburcu version: 0.15.1
> compiled with jemalloc version: 5.3.0
> compiled with libnghttp2 version: 1.64.0
> linked to libnghttp2 version: 1.64.0
> 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: /usr/local/etc/named.conf
> rndc configuration: /usr/local/etc/rndc.conf
> nsupdate session key: /usr/local/var/run/named/session.key
> named PID file: /usr/local/var/run/named/named.pid
> ```
>
>
> *### Steps to reproduce*
>
> 1. Use configuration file below.
> 2. Start BIND server with command: `named -g -c named.conf ...`
>
> *### What is the current *bug* behavior?*
>
> BIND core-dumps and exits.
>
> *### What is the expected *correct* behavior?*
>
> BIND should use the default setting for max-cache-size according to the
> [documentation](https://bind9.readthedocs.io/en/stable/
> reference.html#namedconf-statement-max-cache-size):
>
> > The default size limit for each individual cache is:
> > * 90% of physical memory for views with recursion set to yes (the
> default), or
> > * 2 MB for views with recursion set to no.
>
> *### Relevant configuration files*
>
> named.conf
>
> ```
> controls {};
> options {
> forward only;
> forwarders { ::1; };
> listen-on port 8053 { 127.0.0.1; };
> listen-on-v6 port 8053 { ::1; };
> max-cache-size default;
> empty-zones-enable no;
> session-keyfile "session.key";
> };
> logging {
> category default { default_debug; };
> category unmatched { null; };
> };
> ```
>
>
> *### Relevant logs*
>
> ```
> 14-Sep-2025 13:33:24.314 starting BIND 9.20.14-dev (Stable Release) <id:1cbd8b8>
> 14-Sep-2025 13:33:24.314 running on Linux x86_64 6.14.0-29-generic #29-Ubuntu SMP PREEMPT_DYNAMIC Thu Aug 7 18:32:38 UTC 2025
> 14-Sep-2025 13:33:24.314 built with default
> 14-Sep-2025 13:33:24.314 running as: named -g -n 1 -c named.conf
> 14-Sep-2025 13:33:24.314 compiled by GCC 14.2.0
> 14-Sep-2025 13:33:24.314 compiled with OpenSSL version: OpenSSL 3.4.1 11 Feb 2025
> 14-Sep-2025 13:33:24.314 linked to OpenSSL version: OpenSSL 3.4.1 11 Feb 2025
> 14-Sep-2025 13:33:24.314 compiled with libuv version: 1.50.0
> 14-Sep-2025 13:33:24.314 linked to libuv version: 1.50.0
> 14-Sep-2025 13:33:24.314 compiled with liburcu version: 0.15.1
> 14-Sep-2025 13:33:24.314 compiled with jemalloc version: 5.3.0
> 14-Sep-2025 13:33:24.314 compiled with libnghttp2 version: 1.64.0
> 14-Sep-2025 13:33:24.314 linked to libnghttp2 version: 1.64.0
> 14-Sep-2025 13:33:24.314 compiled with zlib version: 1.3.1
> 14-Sep-2025 13:33:24.314 linked to zlib version: 1.3.1
> 14-Sep-2025 13:33:24.314 ----------------------------------------------------
> 14-Sep-2025 13:33:24.314 BIND 9 is maintained by Internet Systems Consortium,
> 14-Sep-2025 13:33:24.314 Inc. (ISC), a non-profit 501(c)(3) public-benefit
> 14-Sep-2025 13:33:24.314 corporation. Support and training for BIND 9 are
> 14-Sep-2025 13:33:24.314 available athttps://www.isc.org/support
> 14-Sep-2025 13:33:24.314 ----------------------------------------------------
> 14-Sep-2025 13:33:24.314 adjusted limit on open files from 1024 to 1073741816
> 14-Sep-2025 13:33:24.314 found 8 CPUs, using 1 worker thread
> 14-Sep-2025 13:33:24.316 DNSSEC algorithms: RSASHA1 NSEC3RSASHA1 RSASHA256 RSASHA512 ECDSAP256SHA256 ECDSAP384SHA384 ED25519 ED448
> 14-Sep-2025 13:33:24.316 DS algorithms: SHA-1 SHA-256 SHA-384
> 14-Sep-2025 13:33:24.316 HMAC algorithms: HMAC-MD5 HMAC-SHA1 HMAC-SHA224 HMAC-SHA256 HMAC-SHA384 HMAC-SHA512
> 14-Sep-2025 13:33:24.316 TKEY mode 2 support (Diffie-Hellman): no
> 14-Sep-2025 13:33:24.316 TKEY mode 3 support (GSS-API): no
> 14-Sep-2025 13:33:24.317 the initial working directory is '/home/nick/Development/opensource/bind9/nick'
> 14-Sep-2025 13:33:24.317 loading configuration from '/home/nick/Development/opensource/bind9/nick/named.conf'
> 14-Sep-2025 13:33:24.317 using default UDP/IPv4 port range: [32768, 60999]
> 14-Sep-2025 13:33:24.317 using default UDP/IPv6 port range: [32768, 60999]
> 14-Sep-2025 13:33:24.318 listening on IPv4 interface lo, 127.0.0.1#8053
> 14-Sep-2025 13:33:24.318 listening on IPv6 interface lo, ::1#8053
> 14-Sep-2025 13:33:24.318 Disabling periodic interface re-scans timer
> 14-Sep-2025 13:33:24.318 couldn't mkdir '/usr/local/var': Permission denied
> 14-Sep-2025 13:33:24.318 generating session key for dynamic DNS
> 14-Sep-2025 13:33:24.319 server.c:4480: INSIST(strcasecmp(str, "unlimited") == 0) failed
> 14-Sep-2025 13:33:24.319 /home/nick/Development/opensource/bind9/lib/isc/.libs/libisc-9.20.14-dev.so(isc_backtrace_log+0x3f) [0x74a24afa5d3f]
> 14-Sep-2025 13:33:24.319 /home/nick/Development/opensource/bind9/bin/named/.libs/named(+0x278bb) [0x615c2e0348bb]
> 14-Sep-2025 13:33:24.319 /home/nick/Development/opensource/bind9/lib/isc/.libs/libisc-9.20.14-dev.so(isc_assertion_failed+0x10) [0x74a24afa5890]
> 14-Sep-2025 13:33:24.319 /home/nick/Development/opensource/bind9/bin/named/.libs/named(+0x3bf3b) [0x615c2e048f3b]
> 14-Sep-2025 13:33:24.319 /home/nick/Development/opensource/bind9/bin/named/.libs/named(+0x4a01a) [0x615c2e05701a]
> 14-Sep-2025 13:33:24.319 /home/nick/Development/opensource/bind9/bin/named/.libs/named(+0x4ad3d) [0x615c2e057d3d]
> 14-Sep-2025 13:33:24.319 /home/nick/Development/opensource/bind9/lib/isc/.libs/libisc-9.20.14-dev.so(isc__async_cb+0xa7) [0x74a24afa5bd7]
> 14-Sep-2025 13:33:24.319 /lib/x86_64-linux-gnu/libuv.so.1(+0xb933) [0x74a24ae9d933]
> 14-Sep-2025 13:33:24.319 /lib/x86_64-linux-gnu/libuv.so.1(+0x2bd9c) [0x74a24aebdd9c]
> 14-Sep-2025 13:33:24.319 /lib/x86_64-linux-gnu/libuv.so.1(uv_run+0x247) [0x74a24aeaaa47]
> 14-Sep-2025 13:33:24.319 /home/nick/Development/opensource/bind9/lib/isc/.libs/libisc-9.20.14-dev.so(+0x4c17e) [0x74a24afb917e]
> 14-Sep-2025 13:33:24.319 /home/nick/Development/opensource/bind9/bin/named/.libs/named(main+0xe02) [0x615c2e028ab2]
> 14-Sep-2025 13:33:24.319 /lib/x86_64-linux-gnu/libc.so.6(+0x2a578) [0x74a24a22a578]
> 14-Sep-2025 13:33:24.319 /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x8b) [0x74a24a22a63b]
> 14-Sep-2025 13:33:24.319 /home/nick/Development/opensource/bind9/bin/named/.libs/named(_start+0x25) [0x615c2e0294c5]
> 14-Sep-2025 13:33:24.319 exiting (due to assertion failure)
> Aborted (core dumped)
> ```
>
>
> /label ~Bug
Thank you for the detailed report. I copied it to GitLab for you:
https://gitlab.isc.org/isc-projects/bind9/-/issues/5518
-Doug
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