login: panic: fifo_badop called Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND * 13591 66636 0 0 0 0 syz-executor7705 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic() at panic+0x147 sys/kern/subr_prf.c:208 fifo_badop(ffffffff8155e002) at fifo_badop+0x12 sys/miscfs/fifofs/fifo_vnops.c:491 VOP_STRATEGY(58295b3d52b3ccf1) at VOP_STRATEGY+0x73 sys/kern/vfs_vops.c:715 bwrite(29631de118140d93) at bwrite+0x1a1 sys/kern/vfs_bio.c:742 VOP_BWRITE(1e474ee9fcc104e8) at VOP_BWRITE+0x4f sys/kern/vfs_vops.c:727 ufs_mkdir(295c060a93b8273a) at ufs_mkdir+0x5a9 sys/ufs/ufs/ufs_vnops.c:1250 VOP_MKDIR(2ab59d7ac4f3a640,ffff8000149ec4c0,1ed,ffffff9c) at VOP_MKDIR+0x6d sys/kern/vfs_vops.c:445 domkdirat(58af1e02137c511a,ffff800014a2ad40,ffff8000149ec4c0,ffff8000ffff73c0) a t domkdirat+0x11c syscall(737c34a5f5960929) at syscall+0x3de Xsyscall(6,88,14087,88,7f7fffff73a0,7f7fffff73c4) at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff73f0, 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+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic() at panic+0x147 sys/kern/subr_prf.c:208 fifo_badop(ffffffff8155e002) at fifo_badop+0x12 sys/miscfs/fifofs/fifo_vnops.c:491 VOP_STRATEGY(58295b3d52b3ccf1) at VOP_STRATEGY+0x73 sys/kern/vfs_vops.c:715 bwrite(29631de118140d93) at bwrite+0x1a1 sys/kern/vfs_bio.c:742 VOP_BWRITE(1e474ee9fcc104e8) at VOP_BWRITE+0x4f sys/kern/vfs_vops.c:727 ufs_mkdir(295c060a93b8273a) at ufs_mkdir+0x5a9 sys/ufs/ufs/ufs_vnops.c:1250 VOP_MKDIR(2ab59d7ac4f3a640,ffff8000149ec4c0,1ed,ffffff9c) at VOP_MKDIR+0x6d sys/kern/vfs_vops.c:445 domkdirat(58af1e02137c511a,ffff800014a2ad40,ffff8000149ec4c0,ffff8000ffff73c0) at domkdirat+0x11c sys/kern/vfs_syscalls.c:2865 syscall(737c34a5f5960929) at syscall+0x3de Xsyscall(6,88,14087,88,7f7fffff73a0,7f7fffff73c4) at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff73f0, count: -11 ddb> show registers rdi 0xffffffff81ef8a48 kprintf_mutex rsi 0x5 rbp 0xffff800014a2a780 rbx 0xffff800014a2a820 rdx 0x3fd rcx 0 rax 0x1 r8 0xffff800014a2a750 r9 0 r10 0xffff800014a2a580 r11 0x1ab53f9e73e579a5 r12 0x3000000008 r13 0xffff800014a2a790 r14 0x100 r15 0xffffffff81c54503 apollo_pio_rec+0x1456 rip 0xffffffff81854218 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800014a2a770 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor7705) pid=13591 stat=onproc flags process=0 proc=0 pri=17, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff8000149ec970,0xffff8000149ec278 process=0xffff8000ffff73c0 user=0xffff800014a25000, vmspace=0xffffff003f12b210 estcpu=36, cpticks=1, pctcpu=0.3 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 98755 478136 74728 0 2 0 syz-executor7705 *66636 13591 74728 0 7 0 syz-executor7705 74728 61155 73050 0 3 0x82 nanosleep syz-executor7705 73050 156267 15159 0 3 0x10008a pause ksh 15159 226182 51458 0 3 0x92 select sshd 10982 420602 1 0 3 0x100083 ttyin getty 51458 291548 1 0 3 0x80 select sshd 73456 39612 23241 73 3 0x100090 kqread syslogd 23241 331804 1 0 3 0x100082 netio syslogd 99520 523392 1 77 3 0x100090 poll dhclient 16809 215148 1 0 3 0x80 poll dhclient 80553 516731 0 0 3 0x14200 pgzero zerothread 85773 360585 0 0 3 0x14200 aiodoned aiodoned 43426 245313 0 0 3 0x14200 syncer update 63356 174938 0 0 3 0x14200 cleaner cleaner 13662 87698 0 0 3 0x14200 reaper reaper 8512 45468 0 0 3 0x14200 pgdaemon pagedaemon 25222 403787 0 0 3 0x14200 bored crynlk 79053 358042 0 0 3 0x14200 bored crypto 48382 471172 0 0 3 0x40014200 acpi0 acpi0 54372 139149 0 0 3 0x14200 bored softnet 30998 138607 0 0 3 0x14200 bored systqmp 59529 376853 0 0 3 0x14200 bored systq 8204 348144 0 0 3 0x40014200 bored softclock 38121 496732 0 0 3 0x40014200 idle0 1 358644 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper