Tested on Rock64:
```
panic: kdb_sysctl_panic
cpuid = 3
time = 1641841341
KDB: stack backtrace:
db_trace_self() at db_trace_self
db_trace_self_wrapper() at db_trace_self_wrapper+0x30
vpanic() at vpanic+0x174
panic() at panic+0x44
kdb_sysctl_panic() at kdb_sysctl_panic+0x68
sysctl_root_handler_locked() at sysctl_root_handler_locked+0xe0
sysctl_root() at sysctl_root+0x1ac
userland_sysctl() at userland_sysctl+0x140
sys___sysctl() at sys___sysctl+0x68
do_el0_sync() at do_el0_sync+0x4b0
handle_el0_sync() at handle_el0_sync+0x90
--- exception, esr 0x56000000
Uptime: 1m55s
Dumping 161 out of 996 MB:..3%..13%..23%..33%..43%..53%..62%..72%..82%..92%
Dump complete
```
After the reboot:
```
Jan 10 19:04:53 rock64b savecore[896]: reboot after panic: kdb_sysctl_panic
Writing crash summary to /var/crash/core.txt.3.
```
The vmcore file was usable with kgdb.
zpool scrub did not detect any damage (writes outside of the swap / dump partition).