login: uvm_fault(0xffffffff83aa4028, 0xffff8000286e2008, 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
*221960  58185      0           0  0x4000001    0  syz-executor
ffs2_balloc(fffff10070241900,35a07,50,fffff10007ffda28,1,ffff80002a761478) at ffs2_balloc+0xa0a sys/ufs/ffs/ffs_balloc.c:614
ffs_write(ffff80002a761500) at ffs_write+0x4f9 sys/ufs/ffs/ffs_vnops.c:345
VOP_WRITE(fffff10067191020,ffff80002a7615b0,3,fffff10007ffda28) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
ktrwriteraw(ffff80002a75a548,fffff10067191020,fffff10007ffda28,ffff80002a761680,ffff80002a761660) at ktrwriteraw+0x19b sys/kern/kern_ktrace.c:692
ktrsysret(ffff80002a75a548,36,0,ffff80002a761740) at ktrsysret+0x17f ktrwrite2 sys/kern/kern_ktrace.c:-1 [inline]
ktrsysret(ffff80002a75a548,36,0,ffff80002a761740) at ktrsysret+0x17f sys/kern/kern_ktrace.c:209
syscall(ffff80002a7617f0) at syscall+0xad9 mi_syscall_return sys/sys/syscall_mi.h:204 [inline]
syscall(ffff80002a7617f0) at syscall+0xad9 sys/arch/amd64/amd64/trap.c:804
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xc046c6520e0, 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> 
ddb> set $lines = 0
ddb> set $maxwidth = 0
ddb> show panic
*cpu0: uvm_fault(0xffffffff83aa4028, 0xffff8000286e2008, 0, 1) -> d
ddb> show kasan
No such command
ddb> trace
ffs2_balloc(fffff10070241900,35a07,50,fffff10007ffda28,1,ffff80002a761478) at ffs2_balloc+0xa0a sys/ufs/ffs/ffs_balloc.c:614
ffs_write(ffff80002a761500) at ffs_write+0x4f9 sys/ufs/ffs/ffs_vnops.c:345
VOP_WRITE(fffff10067191020,ffff80002a7615b0,3,fffff10007ffda28) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
ktrwriteraw(ffff80002a75a548,fffff10067191020,fffff10007ffda28,ffff80002a761680,ffff80002a761660) at ktrwriteraw+0x19b sys/kern/kern_ktrace.c:692
ktrsysret(ffff80002a75a548,36,0,ffff80002a761740) at ktrsysret+0x17f ktrwrite2 sys/kern/kern_ktrace.c:-1 [inline]
ktrsysret(ffff80002a75a548,36,0,ffff80002a761740) at ktrsysret+0x17f sys/kern/kern_ktrace.c:209
syscall(ffff80002a7617f0) at syscall+0xad9 mi_syscall_return sys/sys/syscall_mi.h:204 [inline]
syscall(ffff80002a7617f0) at syscall+0xad9 sys/arch/amd64/amd64/trap.c:804
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xc046c6520e0, count: -7
ddb> show registers
rdi                                0
rsi                                0
rbp               0xffff80002a761420
rbx               0xfffff10070241900
rdx                                0
rcx               0xffff8000286e2000
rax                              0x1
r8                0xffffffffffffffff
r9                0xffff80002a761478
r10               0xb3588a2dc7c7e2f2
r11               0x63de584c70dd7bcc
r12                              0x1
r13               0xffff800000c48800
r14               0xffff80002a7612c0
r15               0xfffff10070e81120
rip               0xffffffff8126ca0a    ffs2_balloc+0xa0a
cs                               0x8
rflags                       0x10246    __ALIGN_SIZE+0xf246
rsp               0xffff80002a7612b0
ss                              0x10
ffs2_balloc+0xa0a:      movq    0(%rcx,%rax,8),%r14
ddb> show proc
PROC (syz-executor) tid=221960 pid=58185 tcnt=3 stat=onproc
    flags process=0 proc=4000001<INKTR,THREAD>
    runpri=32, usrpri=81, slppri=32, nice=20
    wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
    forw=0xffffffffffffffff, list=0xffff80002a75a7e0,0xffff80002a75afb8
    process=0xffff80002a745208 user=0xffff80002a75c000, vmspace=0xfffff1006d186180
    estcpu=36, cpticks=1, pctcpu=0.0, user=0, sys=1, intr=0
ddb>