uvm_fault(0xffffffff83a268f8, 0xffff8000298e200c, 0, 1) -> d kernel: page fault trap, code=0 Stopped at ufs_direnter+0x23b: movl 0(%r14),%r15d TID PID UID PRFLAGS PFLAGS CPU COMMAND 517960 79289 0 0 0 0 syz-executor *325379 27189 0 0x2 0 1K syz-executor ufs_direnter(fffffd806124f060,fffffd80699f8e98,ffff80002a3a64d0,ffff80002a3a6800,fffffd805e367158) at ufs_direnter+0x23b sys/ufs/ufs/ufs_lookup.c:764 ufs_mkdir(ffff80002a3a6670) at ufs_mkdir+0x5d5 sys/ufs/ufs/ufs_vnops.c:1179 VOP_MKDIR(fffffd806124f060,ffff80002a3a67d0,ffff80002a3a6800,ffff80002a3a6700) at VOP_MKDIR+0x101 sys/kern/vfs_vops.c:394 domkdirat(ffff80003c3fc808,ffffff9c,7f208d8aefc0,1ff) at domkdirat+0x179 sys/kern/vfs_syscalls.c:3143 syscall(ffff80002a3a6980) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80002a3a6980) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:783 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f208d8af060, count: 9 https://www.openbsd.org/ddb.html describes the minimum info required in bug reports. Insufficient info makes it difficult to find and fix bugs.