uvm_fault(0xffffffff83949d90, 0xffff8000297e3fe9, 0, 2) -> d
kernel: page fault trap, code=2
Stopped at      memset+0x49:    repe stosb      %es:(%rdi)
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*429618  56950      0         0x2        0x1    0  syz-executor
memset() at memset+0x49
ffs_write(ffff80002a8b3bb0) at ffs_write+0xb9a sys/ufs/ffs/ffs_vnops.c:401
VOP_WRITE(fffffd8069ace110,ffff80002a8b3c60,3,fffffd8007ffd548) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
ktrwriteraw(ffff80002a7467d0,fffffd8069ace110,fffffd8007ffd548,ffff80002a8b3d30,ffff80002a8b3d10) at ktrwriteraw+0x19b sys/kern/kern_ktrace.c:691
ktrsysret(ffff80002a7467d0,5b,0,ffff80002a8b3df0) at ktrsysret+0x17f ktrwrite2 sys/kern/kern_ktrace.c:-1 [inline]
ktrsysret(ffff80002a7467d0,5b,0,ffff80002a8b3df0) at ktrsysret+0x17f sys/kern/kern_ktrace.c:209
syscall(ffff80002a8b3ea0) at syscall+0xad9 mi_syscall_return sys/sys/syscall_mi.h:204 [inline]
syscall(ffff80002a8b3ea0) at syscall+0xad9 sys/arch/amd64/amd64/trap.c:804
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x71550e48d4e0, 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(0xffffffff83949d90, 0xffff8000297e3fe9, 0, 2) -> d
ddb> trace
memset() at memset+0x49
ffs_write(ffff80002a8b3bb0) at ffs_write+0xb9a sys/ufs/ffs/ffs_vnops.c:401
VOP_WRITE(fffffd8069ace110,ffff80002a8b3c60,3,fffffd8007ffd548) at VOP_WRITE+0x101 sys/kern/vfs_vops.c:245
ktrwriteraw(ffff80002a7467d0,fffffd8069ace110,fffffd8007ffd548,ffff80002a8b3d30,ffff80002a8b3d10) at ktrwriteraw+0x19b sys/kern/kern_ktrace.c:691
ktrsysret(ffff80002a7467d0,5b,0,ffff80002a8b3df0) at ktrsysret+0x17f ktrwrite2 sys/kern/kern_ktrace.c:-1 [inline]
ktrsysret(ffff80002a7467d0,5b,0,ffff80002a8b3df0) at ktrsysret+0x17f sys/kern/kern_ktrace.c:209
syscall(ffff80002a8b3ea0) at syscall+0xad9 mi_syscall_return sys/sys/syscall_mi.h:204 [inline]
syscall(ffff80002a8b3ea0) at syscall+0xad9 sys/arch/amd64/amd64/trap.c:804
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x71550e48d4e0, count: -7
ddb>