uvm_fault(0xffffffff83b11080, 0xffff800029682050, 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
*235005  68869      0         0x2        0x1    1K syz-executor
  52706  73082      0         0x2        0x1    0  syz-executor
ffs2_balloc(fffffd8065423ce8,5a1a6,50,fffffd80097fd3a8,1,ffff80002a379d48) at ffs2_balloc+0xa0d sys/ufs/ffs/ffs_balloc.c:614
ffs_write(ffff80002a379dd0) at ffs_write+0x4f9 sys/ufs/ffs/ffs_vnops.c:345
VOP_WRITE(fffffd8068932d08,ffff80002a379e80,3,fffffd80097fd3a8) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
ktrwriteraw(ffff8000fffee7e0,fffffd8068932d08,fffffd80097fd3a8,ffff80002a379f50,ffff80002a379f30) at ktrwriteraw+0x1be sys/kern/kern_ktrace.c:692
ktrsysret(ffff8000fffee7e0,5b,0,ffff80002a37a020) at ktrsysret+0x192 ktrwrite2 sys/kern/kern_ktrace.c:-1 [inline]
ktrsysret(ffff8000fffee7e0,5b,0,ffff80002a37a020) at ktrsysret+0x192 sys/kern/kern_ktrace.c:209
syscall(ffff80002a37a0d0) at syscall+0xa51 mi_syscall_return sys/sys/syscall_mi.h:204 [inline]
syscall(ffff80002a37a0d0) at syscall+0xa51 sys/arch/amd64/amd64/trap.c:804
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7d08f6d59b70, count: 8
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(0xffffffff83b11080, 0xffff800029682050, 0, 1) -> d
ddb{1}> trace
ffs2_balloc(fffffd8065423ce8,5a1a6,50,fffffd80097fd3a8,1,ffff80002a379d48) at ffs2_balloc+0xa0d sys/ufs/ffs/ffs_balloc.c:614
ffs_write(ffff80002a379dd0) at ffs_write+0x4f9 sys/ufs/ffs/ffs_vnops.c:345
VOP_WRITE(fffffd8068932d08,ffff80002a379e80,3,fffffd80097fd3a8) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
ktrwriteraw(ffff8000fffee7e0,fffffd8068932d08,fffffd80097fd3a8,ffff80002a379f50,ffff80002a379f30) at ktrwriteraw+0x1be sys/kern/kern_ktrace.c:692
ktrsysret(ffff8000fffee7e0,5b,0,ffff80002a37a020) at ktrsysret+0x192 ktrwrite2 sys/kern/kern_ktrace.c:-1 [inline]
ktrsysret(ffff8000fffee7e0,5b,0,ffff80002a37a020) at ktrsysret+0x192 sys/kern/kern_ktrace.c:209
syscall(ffff80002a37a0d0) at syscall+0xa51 mi_syscall_return sys/sys/syscall_mi.h:204 [inline]
syscall(ffff80002a37a0d0) at syscall+0xa51 sys/arch/amd64/amd64/trap.c:804
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7d08f6d59b70, count: -7
ddb{1}> show registers
rdi                                0
rsi                                0
rbp               0xffff80002a379cf0
rbx                                0
rdx                                0
rcx               0xffff800029682000
rax                              0xa
r8                0xffffffffffffffff
r9                0xffff80002a379d48
r10               0xf31bb9f9d969abb6
r11               0xadb464c8f041b813
r12                              0x1
r13               0xffff800000c31800
r14               0xffff80002a379b80
r15               0xfffffd807473b6b8
rip               0xffffffff8139258d    ffs2_balloc+0xa0d
cs                               0x8
rflags                       0x10246    __ALIGN_SIZE+0xf246
rsp               0xffff80002a379b70
ss                                 0
ffs2_balloc+0xa0d:      movq    0(%rcx,%rax,8),%r14
ddb{1}> show proc
PROC (syz-executor) tid=235005 pid=68869 tcnt=1 stat=onproc
    flags process=2<EXEC> proc=1<INKTR>
    runpri=32, usrpri=83, slppri=32, nice=20
    wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
    forw=0xffffffffffffffff, list=0xffff8000fffeea78,0xffff8000fffeed20
    process=0xffff80002a37f038 user=0xffff80002a375000, vmspace=0xfffffd806f39b7a8
    estcpu=33, cpticks=259, pctcpu=1.58, user=1, sys=257, intr=0
ddb{1}>