panic: witness_warn Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *459640 3517 32767 0x10 0x4000000 0 syz-executor1 145907 22670 32767 0x10 0 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(323f4fb3281fdd7c,0,ffff800020b932d8) at witness_warn+0x6e0 witness_debugger sys/kern/subr_witness.c:2546 [inline] witness_warn(323f4fb3281fdd7c,0,ffff800020b932d8) at witness_warn+0x6e0 sys/kern/subr_witness.c:1462 userret(69763d8168b0e218) at userret+0x361 sys/kern/kern_sig.c:1899 syscall(1b256a17fcd413ba) at syscall+0x680 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(1b256a17fcd413ba) at syscall+0x680 sys/arch/amd64/amd64/trap.c:605 Xsyscall(6,5,c,0,3,b24e5625010) at Xsyscall+0x128 end of kernel end trace frame: 0xb275e8b7750, 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(323f4fb3281fdd7c,0,ffff800020b932d8) at witness_warn+0x6e0 witness_debugger sys/kern/subr_witness.c:2546 [inline] witness_warn(323f4fb3281fdd7c,0,ffff800020b932d8) at witness_warn+0x6e0 sys/kern/subr_witness.c:1462 userret(69763d8168b0e218) at userret+0x361 sys/kern/kern_sig.c:1899 syscall(1b256a17fcd413ba) at syscall+0x680 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(1b256a17fcd413ba) at syscall+0x680 sys/arch/amd64/amd64/trap.c:605 Xsyscall(6,5,c,0,3,b24e5625010) at Xsyscall+0x128 end of kernel end trace frame: 0xb275e8b7750, count: -6 ddb{0}> show registers rdi 0xffffffff81391847 db_enter+0x17 rsi 0x59fd __ALIGN_SIZE+0x49fd rbp 0xffff800020c6ce50 rbx 0xffff800020c6cef0 rdx 0x59fe __ALIGN_SIZE+0x49fe rcx 0xffff80000454e000 rax 0xffff80000454e000 r8 0xffffffff815d9fe4 kprintf+0x174 r9 0x1 r10 0x6b0a39b05c155512 r11 0xa72a68ec1f04b188 r12 0x3000000008 r13 0xffff800020c6ce60 r14 0x100 r15 0x1 rip 0xffffffff81391848 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020c6ce40 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor1) pid=459640 stat=onproc flags process=10 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800020b93530,0xffff800020b93c48 process=0xffff800020bca360 user=0xffff800020c68000, vmspace=0xfffffd807f00d2d0 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 3517 407366 81231 32767 2 0x10 syz-executor1 * 3517 459640 81231 32767 7 0x4000010 syz-executor1 3517 410879 81231 32767 2 0x4000010 syz-executor1 3517 231050 81231 32767 3 0x4000090 fsleep syz-executor1 3517 142882 81231 32767 2 0x4000010 syz-executor1 81231 29415 80483 32767 2 0x490 syz-executor1 80483 284868 82697 0 3 0x82 wait syz-executor1 22670 145907 15126 32767 7 0x10 syz-executor0 15126 367408 82697 0 3 0x82 wait syz-executor0 75448 385826 0 0 3 0x14200 bored sosplice 82697 249473 92817 0 3 0x82 thrsleep syz-fuzzer 82697 93175 92817 0 2 0x4000482 syz-fuzzer 82697 150339 92817 0 3 0x4000082 thrsleep syz-fuzzer 82697 44271 92817 0 2 0x4000482 syz-fuzzer 82697 3486 92817 0 3 0x4000082 thrsleep syz-fuzzer 82697 320383 92817 0 3 0x4000082 thrsleep syz-fuzzer 82697 120330 92817 0 3 0x4000082 thrsleep syz-fuzzer 82697 400329 92817 0 3 0x4000082 thrsleep syz-fuzzer 82697 160304 92817 0 3 0x4000082 thrsleep syz-fuzzer 82697 179850 92817 0 3 0x4000082 kqread syz-fuzzer 92817 427247 51890 0 3 0x10008a pause ksh 51890 173946 12417 0 3 0x92 select sshd 95129 81207 1 0 3 0x100083 ttyin getty 12417 419643 1 0 3 0x80 select sshd 40561 132857 23567 73 2 0x100010 syslogd 23567 430179 1 0 3 0x100082 netio syslogd 91022 173180 1 77 3 0x100090 poll dhclient 60168 112171 1 0 3 0x80 poll dhclient 13156 394838 0 0 2 0x14200 zerothread 93528 511170 0 0 3 0x14200 aiodoned aiodoned 20452 244728 0 0 3 0x14200 syncer update 21402 238613 0 0 3 0x14200 cleaner cleaner 36328 136879 0 0 3 0x14200 reaper reaper 77073 245142 0 0 3 0x14200 pgdaemon pagedaemon 1653 414996 0 0 3 0x14200 bored crynlk 47716 246598 0 0 3 0x14200 bored crypto 15056 118545 0 0 3 0x40014200 acpi0 acpi0 50345 347246 0 0 3 0x40014200 idle1 37633 513465 0 0 3 0x14200 bored softnet 18813 150196 0 0 3 0x14200 bored systqmp 20408 123025 0 0 3 0x14200 bored systq 15622 392442 0 0 3 0x40014200 bored softclock 25279 111463 0 0 3 0x40014200 idle0 1 72686 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper