kern.securelevel: 0 -> 1
creating runtime link editor directory cache.
preserving editor files.
starting network daemons: sshd.
starting local daemons:.
Thu Jan 31 20:44:48 PST 2019

OpenBSD/amd64 (ci-openbsd-multicore-6.c.syzkaller.internal) (tty00)

Warning: Permanently added '10.128.0.156' (ECDSA) to the list of known hosts.
2019/01/31 20:45:23 parsed 1 programs
2019/01/31 20:45:29 executed programs: 0
login: witness: thread 0xffff800020b752c8 exiting with the following locks held:

exclusive rrwlock inode r = 0 (0xfffffd806bbcc928) locked @ /syzkaller/managers/multicore/kernel/sys/ufs/ufs/ufs_vnops.c:1547

panic: thread 0xffff800020b752c8 cannot exit while holding sleeplocks

Stopped at      db_enter+0x18:  addq    $0x8,%rsp

    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND

* 39170  83009      0     0x14000      0x200    1  reaper

db_enter() at db_enter+0x18

panic() at panic+0x16c

witness_thread_exit(16dd2bc53ae603fa) at witness_thread_exit+0x244

reaper(0) at reaper+0x14f

end trace frame: 0x0, count: 11

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{1}> 

ddb{1}> set $lines = 0

ddb{1}> show panic

thread 0xffff800020b752c8 cannot exit while holding sleeplocks

ddb{1}> trace

db_enter() at db_enter+0x18

panic() at panic+0x16c

witness_thread_exit(16dd2bc53ae603fa) at witness_thread_exit+0x244

reaper(0) at reaper+0x14f

end trace frame: 0x0, count: -4

ddb{1}> show registers

rdi                                0

rsi                              0x1

rbp               0xffff800020b67330

rbx               0xffff800020b673d0

rdx               0xffffffff81f323f3    cy_pio_rec+0x25c

rcx                            0x201

rax                              0x1

r8                0xffffffff81d8b924    kprintf+0x174

r9                               0x1

r10               0xb19e7f6ebcc25fe1

r11               0xda47be9ac092cb55

r12                     0x3000000008

r13               0xffff800020b67340

r14                            0x100

r15                              0x1

rip               0xffffffff81202148    db_enter+0x18

cs                               0x8

rflags                         0x246

rsp               0xffff800020b67320

ss                              0x10

db_enter+0x18:  addq    $0x8,%rsp

ddb{1}> show proc

PROC (reaper) pid=39170 stat=onproc

    flags process=14000<NOZOMBIE,SYSTEM> proc=200<SYSTEM>

    pri=4, usrpri=51, nice=20

    forw=0xffffffffffffffff, list=0xffff800020b20e10,0xffff800020b219d8

    process=0xffff800020b5b070 user=0xffff800020b62000, vmspace=0xffffffff822d2290

    estcpu=1, cpticks=3, pctcpu=0.0

    user=0, sys=2, intr=0

ddb{1}>