panic: witness_warn
Stopped at      db_enter+0x18:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 275012  80054      0           0          0    0  syz-executor1
*222134  82641      0           0  0x4000000    1  syz-executor0
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399
panic() at panic+0x16c sys/kern/subr_prf.c:208
witness_warn(b12d714a6fba0a39,0,ffff800020b92720) at witness_warn+0x700 witness_debugger sys/kern/subr_witness.c:2549 [inline]
witness_warn(b12d714a6fba0a39,0,ffff800020b92720) at witness_warn+0x700 sys/kern/subr_witness.c:1465
userret(f28641b0de91c7f0) at userret+0x361 sys/kern/kern_sig.c:1899
syscall(652375833bf62926) at syscall+0x680 mi_syscall_return sys/sys/syscall_mi.h:122 [inline]
syscall(652375833bf62926) at syscall+0x680 sys/arch/amd64/amd64/trap.c:605
Xsyscall(6,5,c,0,3,631f29e3010) at Xsyscall+0x128
end of kernel
end trace frame: 0x634974f04f0, 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.
ddb{1}> 
ddb{1}> set $lines = 0
ddb{1}> show panic
witness_warn
ddb{1}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399
panic() at panic+0x16c sys/kern/subr_prf.c:208
witness_warn(b12d714a6fba0a39,0,ffff800020b92720) at witness_warn+0x700 witness_debugger sys/kern/subr_witness.c:2549 [inline]
witness_warn(b12d714a6fba0a39,0,ffff800020b92720) at witness_warn+0x700 sys/kern/subr_witness.c:1465
userret(f28641b0de91c7f0) at userret+0x361 sys/kern/kern_sig.c:1899
syscall(652375833bf62926) at syscall+0x680 mi_syscall_return sys/sys/syscall_mi.h:122 [inline]
syscall(652375833bf62926) at syscall+0x680 sys/arch/amd64/amd64/trap.c:605
Xsyscall(6,5,c,0,3,631f29e3010) at Xsyscall+0x128
end of kernel
end trace frame: 0x634974f04f0, count: -6
ddb{1}> show registers
rdi                                0
rsi                              0x1
rbp               0xffff800020c93330
rbx               0xffff800020c933d0
rdx               0xffffffff81f3066d    apollo_pio_rec+0x86ea
rcx                            0x201
rax                              0x1
r8                0xffffffff817c1934    kprintf+0x174
r9                               0x1
r10               0x97c505510634d11b
r11               0x86885fbb9cd0d20e
r12                     0x3000000008
r13               0xffff800020c93340
r14                            0x100
r15                              0x1
rip               0xffffffff81598c38    db_enter+0x18
cs                               0x8
rflags                         0x246
rsp               0xffff800020c93320
ss                              0x10
db_enter+0x18:  addq    $0x8,%rsp
ddb{1}> show proc
PROC (syz-executor0) pid=222134 stat=onproc
    flags process=0 proc=4000000<THREAD>
    pri=32, usrpri=65, nice=20
    forw=0xffffffffffffffff, list=0xffff800020b93080,0xffff800020b92028
    process=0xffff800020b95a50 user=0xffff800020c8e000, vmspace=0xfffffd807f00c9d8
    estcpu=15, cpticks=2, pctcpu=0.0
    user=0, sys=2, intr=0
ddb{1}>