panic: witness_warn Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *389765 91720 0 0 0x4000000 0 syz-executor0 343 41303 73 0x100010 0 1 syslogd 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(f5ca5273b19bbfaa,0,ffff800020b92720) at witness_warn+0x6e0 witness_debugger sys/kern/subr_witness.c:2546 [inline] witness_warn(f5ca5273b19bbfaa,0,ffff800020b92720) at witness_warn+0x6e0 sys/kern/subr_witness.c:1462 userret(c5a580cc64e46d84) at userret+0x361 sys/kern/kern_sig.c:1899 syscall(b77126b04c021d3) at syscall+0x680 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(b77126b04c021d3) at syscall+0x680 sys/arch/amd64/amd64/trap.c:605 Xsyscall(6,5,c,0,3,914082571a0) at Xsyscall+0x128 end of kernel end trace frame: 0x9169e2e4b30, 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{0}> ddb{0}> set $lines = 0 ddb{0}> show panic witness_warn ddb{0}> 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(f5ca5273b19bbfaa,0,ffff800020b92720) at witness_warn+0x6e0 witness_debugger sys/kern/subr_witness.c:2546 [inline] witness_warn(f5ca5273b19bbfaa,0,ffff800020b92720) at witness_warn+0x6e0 sys/kern/subr_witness.c:1462 userret(c5a580cc64e46d84) at userret+0x361 sys/kern/kern_sig.c:1899 syscall(b77126b04c021d3) at syscall+0x680 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(b77126b04c021d3) at syscall+0x680 sys/arch/amd64/amd64/trap.c:605 Xsyscall(6,5,c,0,3,914082571a0) at Xsyscall+0x128 end of kernel end trace frame: 0x9169e2e4b30, count: -6 ddb{0}> show registers rdi 0xffffffff81a668f7 db_enter+0x17 rsi 0x443a __ALIGN_SIZE+0x343a rbp 0xffff800020cbee10 rbx 0xffff800020cbeeb0 rdx 0x443b __ALIGN_SIZE+0x343b rcx 0xffff800000d47000 rax 0xffff800000d47000 r8 0xffffffff817cef24 kprintf+0x174 r9 0x1 r10 0xe51b303827a6ee15 r11 0x3a5a7f33e5fcd544 r12 0x3000000008 r13 0xffff800020cbee20 r14 0x100 r15 0x1 rip 0xffffffff81a668f8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020cbee00 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor0) pid=389765 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800020b92018,0xffffffff822e46c8 process=0xffff800020b949e8 user=0xffff800020cba000, vmspace=0xfffffd807f00d9d8 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 91720 140133 30004 0 2 0 syz-executor0 91720 177764 30004 0 3 0x4000080 fsleep syz-executor0 91720 222 30004 0 2 0x4000000 syz-executor0 *91720 389765 30004 0 7 0x4000000 syz-executor0 42097 291757 67881 0 2 0x480 syz-executor1 42097 466851 67881 0 3 0x4000080 tunread syz-executor1 42097 307813 67881 0 3 0x4000080 fsleep syz-executor1 96062 493040 1 0 3 0x100083 ttyin getty 96682 486116 0 0 3 0x14200 bored sosplice 67881 391144 94735 0 2 0x2 syz-executor1 30004 241163 94735 0 2 0x482 syz-executor0 94735 211912 12918 0 3 0x82 thrsleep syz-fuzzer 94735 47816 12918 0 3 0x4000082 thrsleep syz-fuzzer 94735 286414 12918 0 3 0x4000082 thrsleep syz-fuzzer 94735 40005 12918 0 3 0x4000082 thrsleep syz-fuzzer 94735 257877 12918 0 3 0x4000082 thrsleep syz-fuzzer 94735 475494 12918 0 3 0x4000082 thrsleep syz-fuzzer 94735 194987 12918 0 3 0x4000082 thrsleep syz-fuzzer 94735 212082 12918 0 3 0x4000082 thrsleep syz-fuzzer 94735 487592 12918 0 3 0x4000082 thrsleep syz-fuzzer 94735 66117 12918 0 3 0x4000082 thrsleep syz-fuzzer 94735 190866 12918 0 3 0x4000082 kqread syz-fuzzer 94735 248409 12918 0 3 0x4000082 thrsleep syz-fuzzer 12918 393015 16284 0 3 0x10008a pause ksh 16284 328584 70808 0 3 0x92 select sshd 70808 423732 1 0 3 0x80 select sshd 41303 343 62985 73 7 0x100010 syslogd 62985 3669 1 0 3 0x100082 netio syslogd 3278 298791 1 77 3 0x100090 poll dhclient 79984 238041 1 0 3 0x80 poll dhclient 25724 139900 0 0 3 0x14200 pgzero zerothread 76487 340142 0 0 3 0x14200 aiodoned aiodoned 41246 34568 0 0 3 0x14200 syncer update 45315 10201 0 0 3 0x14200 cleaner cleaner 42593 348004 0 0 3 0x14200 reaper reaper 88153 247838 0 0 3 0x14200 pgdaemon pagedaemon 52666 106924 0 0 3 0x14200 bored crynlk 90109 16554 0 0 3 0x14200 bored crypto 9401 450312 0 0 3 0x40014200 acpi0 acpi0 78622 226798 0 0 3 0x40014200 idle1 58756 408620 0 0 3 0x14200 bored softnet 57152 190585 0 0 3 0x14200 bored systqmp 86383 25300 0 0 3 0x14200 bored systq 79651 102975 0 0 3 0x40014200 bored softclock 13295 339066 0 0 3 0x40014200 idle0 1 298785 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper