uvm_fault(0xfffffd80693f2538, 0x0, 0, 1) -> e
kernel: page fault trap, code=0
Stopped at      rw_enter+0x1cc: movq    0(%rax),%r15
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 106651  37386      0   0x8000000          0    1  syz-executor
*250205  15648      0   0x8000002          0    0K syz-executor
rw_enter(0,1) at rw_enter+0x1cc sys/kern/kern_rwlock.c:253
uvm_vnp_setsize(fffffd807cc82210,0) at uvm_vnp_setsize+0x61 sys/uvm/uvm_vnode.c:1456
ffs_truncate(fffffd806833f778,0,4,fffffd807f7d36e8) at ffs_truncate+0x35c sys/ufs/ffs/ffs_inode.c:173
ufs_rmdir(ffff8000371d14d8) at ufs_rmdir+0x374 sys/ufs/ufs/ufs_vnops.c:1265
VOP_RMDIR(fffffd807d9b3898,fffffd807cc82210,ffff8000371d15b8) at VOP_RMDIR+0x19a sys/kern/vfs_vops.c:413
dounlinkat(ffff80002a06c018,ffffff9c,77ce600ad5b0,8) at dounlinkat+0x2e0 sys/kern/vfs_syscalls.c:1885
syscall(ffff8000371d1730) at syscall+0xaf8 mi_syscall sys/sys/syscall_mi.h:179 [inline]
syscall(ffff8000371d1730) at syscall+0xaf8 sys/arch/amd64/amd64/trap.c:577
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x77ce600ad5a0, 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.