uvm_fault(0xffffffff83985b50, 0x588fe028, 0, 1) -> e
kernel: page fault trap, code=0
Stopped at      refcnt_rele+0x158:      movq    0(%rax,%r12,8),%r12
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 509585  13229      0         0x2        0x1    1  syz-executor
*473449  16638      0     0x14000      0x200    0  reaper
refcnt_rele(fffffd807f7d2340) at refcnt_rele+0x158 sys/kern/kern_synch.c:935
crfree(fffffd807f7d2340) at crfree+0x35 sys/kern/kern_prot.c:971
reaper(ffff80002a2f8f68) at reaper+0xba proc_free sys/kern/kern_exit.c:431 [inline]
reaper(ffff80002a2f8f68) at reaper+0xba sys/kern/kern_exit.c:471
end trace frame: 0x0, count: 12
https://www.openbsd.org/ddb.html describes the minimum info required in bug
reports.  Insufficient info makes it difficult to find and fix bugs.