openzfs panic: VERIFY3U(offset, <, dn->dn_datablksz) failed

Hi,

recent current (last commit 2026-04-23-222413).

short:
#3  0xffffffff805502f7 in vpanic (
     fmt=0xffffffff82556d5d "VERIFY3U(offset, <, dn->dn_datablksz) failed 
(%llu < %llu)\n", ap=ap@entry=0xfffffe0228f57c70)
     at /space/system/usr_src/sys/kern/kern_shutdown.c:974
         buf = "VERIFY3U(offset, <, dn->dn_datablksz) failed 
(9223372036854775807 < 24576)\n", '\000' <repeats 180 times>
         __pc = 0x0
         __pc = 0x0
         __pc = 0x0
         other_cpus = {__bits = {16777213, 0 <repeats 15 times>}}
         td = 0xfffff80741b6e780
         bootopt = <unavailable>
         newpanic = <optimized out>

See attachment for a full backtrace. vmcore available.

I can trigger this with a postgresql18 initdb call (I tried an upgrade 
from postgresql 17 to 18, copy & paste of the UPDATING entry for the 
initdb call).

No zpool status issues, I started a scrub to see if it detects some 
issues. This is a 5T pool on spinning drives, so it may take a moment.

Bye,
Alexander.

-- 
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