uvm_fault(0xffffffff83a5f560, 0xffff8000264d27f8, 0, 1) -> d
kernel: page fault trap, code=0
Stopped at      ffs2_balloc+0xa0a:      movq    0(%rcx,%rax,8),%r14
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*206842  84662      0           0  0x4000000    0  syz-executor
ffs2_balloc(fffffd806c969100,42c000,4000,fffffd8007ffd548,2,ffff80003c91d3c8) at ffs2_balloc+0xa0a sys/ufs/ffs/ffs_balloc.c:614
ffs_write(ffff80003c91d450) at ffs_write+0x4f9 sys/ufs/ffs/ffs_vnops.c:345
VOP_WRITE(fffffd8072268378,ffff80003c91d608,7,fffffd8007ffd548) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
vn_write(fffffd8075b036a0,ffff80003c91d608,0) at vn_write+0x1c2 sys/kern/vfs_vnops.c:414
dofilewritev(ffff80002a77cfa8,4,ffff80003c91d608,0,ffff80003c91d6b0) at dofilewritev+0x2bd sys/kern/sys_generic.c:384
sys_write(ffff80002a77cfa8,ffff80003c91d760,ffff80003c91d6b0) at sys_write+0xa2 sys/kern/sys_generic.c:300
syscall(ffff80003c91d760) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003c91d760) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xbdd0b9bd230, count: 7
https://www.openbsd.org/ddb.html describes the minimum info required in bug
reports.  Insufficient info makes it difficult to find and fix bugs.
ddb> 
ddb> set $lines = 0
ddb> set $maxwidth = 0
ddb> show panic
*cpu0: uvm_fault(0xffffffff83a5f560, 0xffff8000264d27f8, 0, 1) -> d
ddb> trace
ffs2_balloc(fffffd806c969100,42c000,4000,fffffd8007ffd548,2,ffff80003c91d3c8) at ffs2_balloc+0xa0a sys/ufs/ffs/ffs_balloc.c:614
ffs_write(ffff80003c91d450) at ffs_write+0x4f9 sys/ufs/ffs/ffs_vnops.c:345
VOP_WRITE(fffffd8072268378,ffff80003c91d608,7,fffffd8007ffd548) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
vn_write(fffffd8075b036a0,ffff80003c91d608,0) at vn_write+0x1c2 sys/kern/vfs_vnops.c:414
dofilewritev(ffff80002a77cfa8,4,ffff80003c91d608,0,ffff80003c91d6b0) at dofilewritev+0x2bd sys/kern/sys_generic.c:384
sys_write(ffff80002a77cfa8,ffff80003c91d760,ffff80003c91d6b0) at sys_write+0xa2 sys/kern/sys_generic.c:300
syscall(ffff80003c91d760) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline]
syscall(ffff80003c91d760) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xbdd0b9bd230, count: -8
ddb>