26.7.6: unbound (and syslog-ng) segfault with signal 11 after upgrade (Hyper-V)

[Nex VII]

Hi,
after upgrading from 26.7.5 to 26.7.6 today, unbound keeps crashing with signal 11, roughly every 6-15 minutes, both at startup and at runtime.

Environment:
- OPNsense 26.7.6 (amd64), VM on Hyper-V
- unbound 1.26.1, unchanged since 18/09 and stable until today
- Unbound with DNSSEC, prefetch, serve-expired, aggressive NSEC, forwarding (DoT); DHCP lease registration off; DNSBL off

Observed (kernel log):
- unbound: 14x "exited on signal 11" since the upgrade, e.g. 19:29, 19:35, 19:41, 19:53, 19:59, 20:10, 20:18
- syslog-ng: 2x signal 11 right after boot
- python3.13: 2x signal 6 (abort)
- No "exited on signal" entries at all in the logs of the previous 4 weeks (since 10/09)
- Unbound logs nothing before dying: the last lines are normal resolution activity. A reboot doesn't help.

Since several unrelated binaries started segfaulting right after the update, this looks like a regression in base/libs rather than in unbound itself. Is anyone else seeing this on 26.7.6? I can enable kern.coredump and provide a backtrace if useful.

Thanks

[franco]

I have the feeling this is about https://github.com/opnsense/src/issues/297 which was supposed to be solved with 26.7.6, not cause more regressions on previously unaffected installs.

Can you try to confirm by downgrading the kernel?

# opnsense-update -zkr 26.7.4
(reboot)


Cheers,
Franco

[Nex VII]

Thanks Franco.

Host: Intel Xeon E-2236, Hyper-V Gen 2 VM with 4 vCPUs and 8 GB static RAM.

What I did:
- opnsense-revert -r 26.7.5 opnsense
- opnsense-update -bk -r 26.7.4
- reboot at 20:58

Current versions: core 26.7.5, base 26.7.4, kernel 26.7.4.

Result: since the reboot (about 1 hour so far) there have been no "exited on signal" entries at all. Before, on 26.7.6, unbound crashed repeatedly, the last time at 20:41.

I'll keep monitoring and will report back here if any crash happens again.

Cheers

[mnaim]

Same problem on Hyper-V.
Other physical machines are ok, no Unbound crashes.