uvm_fault(0xffffffff83a66ec0, 0xffff800027662a64, 0, 2) -> d
kernel: page fault trap, code=2
Stopped at      memset+0x49:    repe stosb      %es:(%rdi)
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*439667  57284      0           0  0x4000001    0  syz-executor
memset() at memset+0x49
ffs_write(ffff80002a7d7160) at ffs_write+0xb9a sys/ufs/ffs/ffs_vnops.c:401
VOP_WRITE(fffff8006a6b4298,ffff80002a7d7210,3,fffff80007ffd750) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
ktrwriteraw(ffff80002a766010,fffff8006a6b4298,fffff80007ffd750,ffff80002a7d72e0,ffff80002a7d72c0) at ktrwriteraw+0x19b sys/kern/kern_ktrace.c:692
ktrsysret(ffff80002a766010,36,0,ffff80002a7d73a0) at ktrsysret+0x17f ktrwrite2 sys/kern/kern_ktrace.c:-1 [inline]
ktrsysret(ffff80002a766010,36,0,ffff80002a7d73a0) at ktrsysret+0x17f sys/kern/kern_ktrace.c:209
syscall(ffff80002a7d7450) at syscall+0xad9 mi_syscall_return sys/sys/syscall_mi.h:204 [inline]
syscall(ffff80002a7d7450) at syscall+0xad9 sys/arch/amd64/amd64/trap.c:804
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x70787591d70, 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(0xffffffff83a66ec0, 0xffff800027662a64, 0, 2) -> d
ddb> trace
memset() at memset+0x49
ffs_write(ffff80002a7d7160) at ffs_write+0xb9a sys/ufs/ffs/ffs_vnops.c:401
VOP_WRITE(fffff8006a6b4298,ffff80002a7d7210,3,fffff80007ffd750) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
ktrwriteraw(ffff80002a766010,fffff8006a6b4298,fffff80007ffd750,ffff80002a7d72e0,ffff80002a7d72c0) at ktrwriteraw+0x19b sys/kern/kern_ktrace.c:692
ktrsysret(ffff80002a766010,36,0,ffff80002a7d73a0) at ktrsysret+0x17f ktrwrite2 sys/kern/kern_ktrace.c:-1 [inline]
ktrsysret(ffff80002a766010,36,0,ffff80002a7d73a0) at ktrsysret+0x17f sys/kern/kern_ktrace.c:209
syscall(ffff80002a7d7450) at syscall+0xad9 mi_syscall_return sys/sys/syscall_mi.h:204 [inline]
syscall(ffff80002a7d7450) at syscall+0xad9 sys/arch/amd64/amd64/trap.c:804
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x70787591d70, count: -7
ddb> show registers
rdi               0xffff800027662a64
rsi                                0
rbp               0xffff80002a7d7080
rbx                          0x10a64    __ALIGN_SIZE+0xfa64
rdx                              0x4
rcx                              0x4
rax                                0
r8                             0x598
r9                0xffff80002a7d6fe0
r10               0x606836de8ebce64a
r11               0xffff800027662a64
r12                            0xa64
r13                           0x1000    __ALIGN_SIZE
r14               0xfffff8006a6b4298
r15                              0x1
rip               0xffffffff8200d1d9    memset+0x49
cs                               0x8
rflags                       0x10202    __ALIGN_SIZE+0xf202
rsp               0xffff80002a7d6e78
ss                              0x10
memset+0x49:    repe stosb      %es:(%rdi)
ddb> show proc
PROC (syz-executor) tid=439667 pid=57284 tcnt=2 stat=onproc
    flags process=0 proc=4000001<INKTR,THREAD>
    runpri=86, usrpri=86, slppri=32, nice=20
    wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
    forw=0xffffffffffffffff, list=0xffff80002a766d08,0xffff8000318b0028
    process=0xffff80002a744008 user=0xffff80002a7d2000, vmspace=0xfffff8007ec5e2e0
    estcpu=36, cpticks=2, pctcpu=0.0, user=0, sys=2, intr=0
ddb>