panic() at panic+0x147 sys/kern/subr_prf.c:208 fifo_badop(ffffffff813caa32) at fifo_badop+0x12 sys/miscfs/fifofs/fifo_vnops.c:491 VOP_STRATEGY(ffffff002ab70800) at VOP_STRATEGY+0x6b sys/kern/vfs_vops.c:715 bwrite(ffff800014ad0540) at bwrite+0x195 sys/kern/vfs_bio.c:742 VOP_BWRITE(ffffff00310108a8) at VOP_BWRITE+0x47 sys/kern/vfs_vops.c:727 ufs_mkdir(ffffffff81e1cbe0) at ufs_mkdir+0x5a9 sys/ufs/ufs/ufs_vnops.c:1247 VOP_MKDIR(ffff800014a33c30,1ed,ffffff9c,ffff800014ad04f8) at VOP_MKDIR+0x65 sys/kern/vfs_vops.c:445 domkdirat(ffff800014ad0730,ffff800014a33c30,ffff8000149cf008,880) at domkdirat+0x10f sys/kern/vfs_syscalls.c:2861 syscall(0) at syscall+0x3e4 Xsyscall(6,88,7f7ffffbc3f0,88,0,7f7ffffbc430) at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffbc460, count: 4 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> show panic fifo_badop called ddb> trace db_enter() at db_enter+0xa sys/arch/amd64/amd64/db_interface.c:399 panic() at panic+0x147 sys/kern/subr_prf.c:208 fifo_badop(ffffffff813caa32) at fifo_badop+0x12 sys/miscfs/fifofs/fifo_vnops.c:491 VOP_STRATEGY(ffffff002ab70800) at VOP_STRATEGY+0x6b sys/kern/vfs_vops.c:715 bwrite(ffff800014ad0540) at bwrite+0x195 sys/kern/vfs_bio.c:742 VOP_BWRITE(ffffff00310108a8) at VOP_BWRITE+0x47 sys/kern/vfs_vops.c:727 ufs_mkdir(ffffffff81e1cbe0) at ufs_mkdir+0x5a9 sys/ufs/ufs/ufs_vnops.c:1247 VOP_MKDIR(ffff800014a33c30,1ed,ffffff9c,ffff800014ad04f8) at VOP_MKDIR+0x65 sys/kern/vfs_vops.c:445 domkdirat(ffff800014ad0730,ffff800014a33c30,ffff8000149cf008,880) at domkdirat+0x10f sys/kern/vfs_syscalls.c:2861 syscall(0) at syscall+0x3e4 Xsyscall(6,88,7f7ffffbc3f0,88,0,7f7ffffbc430) at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffbc460, count: -11 ddb> show registers rdi 0xffffffff81e33eb8 kprintf_mutex rsi 0x5 rbp 0xffff800014ad0180 rbx 0xffff800014ad0220 rdx 0x3fd rcx 0 rax 0 r8 0xffff800014ad0150 r9 0 r10 0xffff800014acffb8 r11 0x8 r12 0x3000000008 r13 0xffff800014ad0190 r14 0x100 r15 0xffffffff81c2bcfb apollo_pio_rec+0x151f rip 0xffffffff81266cba db_enter+0xa cs 0x8 rflags 0x246 rsp 0xffff800014ad0180 ss 0x10 db_enter+0xa: popq %rbp ddb> show proc PROC (syz-executor0) pid=136918 stat=onproc flags process=2 proc=0 pri=17, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800014a339d8,0xffff8000ffffd2d8 process=0xffff8000149cf008 user=0xffff800014acb000, vmspace=0xffffff003f12b000 estcpu=36, cpticks=5, pctcpu=0.0 user=0, sys=5, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 25203 450490 0 0 3 0x14200 bored sosplice *91925 136918 33891 0 7 0x2 syz-executor0 78202 234815 33891 0 2 0x2 syz-executor1 33891 395056 71533 0 3 0x82 thrsleep syz-fuzzer 33891 291397 71533 0 2 0x4000482 syz-fuzzer 33891 51166 71533 0 3 0x4000082 thrsleep syz-fuzzer 33891 158057 71533 0 3 0x4000082 kqread syz-fuzzer 33891 142970 71533 0 3 0x4000082 thrsleep syz-fuzzer 33891 386519 71533 0 3 0x4000082 thrsleep syz-fuzzer 33891 474646 71533 0 3 0x4000082 thrsleep syz-fuzzer 71533 60884 27396 0 3 0x10008a pause ksh 27396 280942 89802 0 3 0x92 select sshd 79978 429175 1 0 3 0x100083 ttyopn getty 89802 503361 1 0 3 0x80 select sshd 55812 290465 35547 73 3 0x100090 kqread syslogd 35547 146386 1 0 3 0x100082 netio syslogd 24003 220286 1 77 3 0x100090 poll dhclient 73709 117060 1 0 3 0x80 poll dhclient 96184 504741 0 0 3 0x14200 pgzero zerothread 42861 126822 0 0 3 0x14200 aiodoned aiodoned 59077 514544 0 0 3 0x14200 syncer update 24968 510686 0 0 3 0x14200 cleaner cleaner 19822 296163 0 0 3 0x14200 reaper reaper 59317 523841 0 0 3 0x14200 pgdaemon pagedaemon 93856 491242 0 0 3 0x14200 bored crynlk 99923 438504 0 0 3 0x14200 bored crypto 60212 155346 0 0 3 0x40014200 acpi0 acpi0 40226 235403 0 0 3 0x14200 bored softnet 61857 180520 0 0 3 0x14200 bored systqmp 86961 3490 0 0 3 0x14200 bored systq 97466 127751 0 0 3 0x40014200 bored softclock 45484 249772 0 0 3 0x40014200 idle0 1 337114 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper