uvm_fault(0xffffffff83a99090, 0xffff8000218e2038, 0, 1) -> d
kernel: page fault trap, code=0
Stopped at      ffs2_balloc+0xa0d:      movq    0(%rcx,%rax,8),%r14
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 225010  75333      0           0  0x4000000    0  syz-executor
*362821  14163      0      0x1000  0x4080000    1K syz-executor
ffs2_balloc(fffffd806f9a55e8,8400ce8000,4000,fffffd80097fd410,2,ffff800035b976b8) at ffs2_balloc+0xa0d sys/ufs/ffs/ffs_balloc.c:614
ffs_write(ffff800035b97740) at ffs_write+0x4f9 sys/ufs/ffs/ffs_vnops.c:345
VOP_WRITE(fffffd807a233eb0,ffff800035b978f8,7,fffffd80097fd410) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
vn_write(fffffd807a0d1960,ffff800035b978f8,0) at vn_write+0x1d3 sys/kern/vfs_vnops.c:414
dofilewritev(ffff80002a222540,4,ffff800035b978f8,0,ffff800035b979b0) at dofilewritev+0x2bd sys/kern/sys_generic.c:384
sys_write(ffff80002a222540,ffff800035b97a60,ffff800035b979b0) at sys_write+0xa2 sys/kern/sys_generic.c:300
syscall(ffff800035b97a60) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff800035b97a60) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xaffe57f2e90, 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{1}> 
ddb{1}> set $lines = 0
ddb{1}> set $maxwidth = 0
ddb{1}> show panic
*cpu1: uvm_fault(0xffffffff83a99090, 0xffff8000218e2038, 0, 1) -> d
ddb{1}> trace
ffs2_balloc(fffffd806f9a55e8,8400ce8000,4000,fffffd80097fd410,2,ffff800035b976b8) at ffs2_balloc+0xa0d sys/ufs/ffs/ffs_balloc.c:614
ffs_write(ffff800035b97740) at ffs_write+0x4f9 sys/ufs/ffs/ffs_vnops.c:345
VOP_WRITE(fffffd807a233eb0,ffff800035b978f8,7,fffffd80097fd410) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
vn_write(fffffd807a0d1960,ffff800035b978f8,0) at vn_write+0x1d3 sys/kern/vfs_vnops.c:414
dofilewritev(ffff80002a222540,4,ffff800035b978f8,0,ffff800035b979b0) at dofilewritev+0x2bd sys/kern/sys_generic.c:384
sys_write(ffff80002a222540,ffff800035b97a60,ffff800035b979b0) at sys_write+0xa2 sys/kern/sys_generic.c:300
syscall(ffff800035b97a60) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff800035b97a60) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xaffe57f2e90, count: -8
ddb{1}> show registers
rdi                                0
rsi                              0x2
rbp               0xffff800035b97660
rbx                                0
rdx               0xffff8000015d15c0
rcx               0xffff8000218e2000
rax                              0x7
r8                0xffffffffffffffff
r9                0xffff800035b976b8
r10               0xf2867a969eb5b24b
r11               0x54e19fb52352f463
r12                              0x1
r13               0xffff800000c31800
r14               0xffff800035b974f0
r15               0xfffffd806281d8d0
rip               0xffffffff828fefed    ffs2_balloc+0xa0d
cs                               0x8
rflags                       0x10246    __ALIGN_SIZE+0xf246
rsp               0xffff800035b974e0
ss                                 0
ffs2_balloc+0xa0d:      movq    0(%rcx,%rax,8),%r14
ddb{1}>