uvm_fault(0xffffffff83a77a80, 0xffff800025b03ca0, 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
 317004  32590      0           0          0    0  syz-executor
* 79436  71906      0      0x1000  0x4080000    1K syz-executor
ffs2_balloc(fffffd8060963968,e80000,4000,fffffd80097fd1a0,2,ffff80003c3f9928) at ffs2_balloc+0xa0d sys/ufs/ffs/ffs_balloc.c:614
ffs_write(ffff80003c3f99b0) at ffs_write+0x4f9 sys/ufs/ffs/ffs_vnops.c:345
VOP_WRITE(fffffd8060c6a110,ffff80003c3f9b68,7,fffffd80097fd1a0) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
vn_write(fffffd8060437548,ffff80003c3f9b68,0) at vn_write+0x1d3 sys/kern/vfs_vnops.c:414
dofilewritev(ffff80003a7c82b8,3,ffff80003c3f9b68,0,ffff80003c3f9c20) at dofilewritev+0x2bd sys/kern/sys_generic.c:384
sys_write(ffff80003a7c82b8,ffff80003c3f9cd0,ffff80003c3f9c20) at sys_write+0xa2 sys/kern/sys_generic.c:300
syscall(ffff80003c3f9cd0) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80003c3f9cd0) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xe023a391cc0, 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(0xffffffff83a77a80, 0xffff800025b03ca0, 0, 1) -> d
ddb{1}> trace
ffs2_balloc(fffffd8060963968,e80000,4000,fffffd80097fd1a0,2,ffff80003c3f9928) at ffs2_balloc+0xa0d sys/ufs/ffs/ffs_balloc.c:614
ffs_write(ffff80003c3f99b0) at ffs_write+0x4f9 sys/ufs/ffs/ffs_vnops.c:345
VOP_WRITE(fffffd8060c6a110,ffff80003c3f9b68,7,fffffd80097fd1a0) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
vn_write(fffffd8060437548,ffff80003c3f9b68,0) at vn_write+0x1d3 sys/kern/vfs_vnops.c:414
dofilewritev(ffff80003a7c82b8,3,ffff80003c3f9b68,0,ffff80003c3f9c20) at dofilewritev+0x2bd sys/kern/sys_generic.c:384
sys_write(ffff80003a7c82b8,ffff80003c3f9cd0,ffff80003c3f9c20) at sys_write+0xa2 sys/kern/sys_generic.c:300
syscall(ffff80003c3f9cd0) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80003c3f9cd0) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xe023a391cc0, count: -8
ddb{1}> show registers
rdi                                0
rsi                              0x2
rbp               0xffff80003c3f98d0
rbx                                0
rdx               0xffff8000015f1900
rcx               0xffff800025b02000
rax                            0x394
r8                0xffffffffffffffff
r9                0xffff80003c3f9928
r10               0x16613edf105dbf13
r11               0xbc9bb2c50b368d83
r12                              0x1
r13               0xffff800000c31800
r14               0xffff80003c3f9760
r15               0xfffffd805fd6ec38
rip               0xffffffff81a3e9fd    ffs2_balloc+0xa0d
cs                               0x8
rflags                       0x10246    __ALIGN_SIZE+0xf246
rsp               0xffff80003c3f9750
ss                              0x10
ffs2_balloc+0xa0d:      movq    0(%rcx,%rax,8),%r14
ddb{1}> show proc
PROC (syz-executor) tid=79436 pid=71906 tcnt=4 stat=onproc
    flags process=1000<SINGLEEXIT> proc=4080000<SUSPSINGLE,THREAD>
    runpri=17, usrpri=72, slppri=17, nice=20
    wchan=0x0, wmesg=, ps_single=0xffff80003a7c9ca8 scnt=3 ecnt=0
    forw=0xffffffffffffffff, list=0xffff80003a7c9ca8,0xffff80003a7c8560
    process=0xffff80003a3a8020 user=0xffff80003c3f4000, vmspace=0xfffffd806c7025d0
    estcpu=22, cpticks=32, pctcpu=0.23, user=0, sys=32, intr=0
ddb{1}>