panic: witness_warn Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *286077 65575 32767 0x1010 0x4080000 1 syz-executor1 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(bf07dfbd739a9cde,0,ffff800020b74710) at witness_warn+0x6e0 witness_debugger sys/kern/subr_witness.c:2546 [inline] witness_warn(bf07dfbd739a9cde,0,ffff800020b74710) at witness_warn+0x6e0 sys/kern/subr_witness.c:1462 userret(d7c826fa003fc304) at userret+0x361 sys/kern/kern_sig.c:1899 syscall(9d844ae15a96c05e) at syscall+0x680 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(9d844ae15a96c05e) at syscall+0x680 sys/arch/amd64/amd64/trap.c:605 Xsyscall(6,5,c,0,3,20221aa9268) at Xsyscall+0x128 end of kernel end trace frame: 0x20486a9c470, 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(bf07dfbd739a9cde,0,ffff800020b74710) at witness_warn+0x6e0 witness_debugger sys/kern/subr_witness.c:2546 [inline] witness_warn(bf07dfbd739a9cde,0,ffff800020b74710) at witness_warn+0x6e0 sys/kern/subr_witness.c:1462 userret(d7c826fa003fc304) at userret+0x361 sys/kern/kern_sig.c:1899 syscall(9d844ae15a96c05e) at syscall+0x680 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(9d844ae15a96c05e) at syscall+0x680 sys/arch/amd64/amd64/trap.c:605 Xsyscall(6,5,c,0,3,20221aa9268) at Xsyscall+0x128 end of kernel end trace frame: 0x20486a9c470, count: -6 ddb{1}> show registers rdi 0xffffffff81391847 db_enter+0x17 rsi 0x7050 __ALIGN_SIZE+0x6050 rbp 0xffff800020cd3230 rbx 0xffff800020cd32d0 rdx 0x7051 __ALIGN_SIZE+0x6051 rcx 0xffff800002b4b000 rax 0xffff800002b4b000 r8 0xffffffff815d9fe4 kprintf+0x174 r9 0x1 r10 0x9080f6065b2b5f7c r11 0x5f583f3bfd8e695d r12 0x3000000008 r13 0xffff800020cd3240 r14 0x100 r15 0x1 rip 0xffffffff81391848 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020cd3220 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor1) pid=286077 stat=onproc flags process=1010 proc=4080000 pri=32, usrpri=81, nice=20 forw=0xffffffffffffffff, list=0xffff800020b939e0,0xffffffff82319e38 process=0xffff800020b95a50 user=0xffff800020cce000, vmspace=0xfffffd806e924cb0 estcpu=31, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 65575 57680 21330 32767 3 0x3010 suspend syz-executor1 *65575 286077 21330 32767 7 0x4081010 syz-executor1 33725 7791 93322 32767 3 0x90 piperd syz-executor0 93322 323745 64753 0 3 0x82 wait syz-executor0 21330 284330 54482 32767 2 0x490 syz-executor1 54482 171152 64753 0 3 0x82 wait syz-executor1 76046 394083 0 0 3 0x14200 bored sosplice 64753 383680 33710 0 3 0x82 thrsleep syz-fuzzer 64753 317190 33710 0 3 0x4000082 thrsleep syz-fuzzer 64753 516051 33710 0 3 0x4000082 thrsleep syz-fuzzer 64753 380248 33710 0 3 0x4000082 thrsleep syz-fuzzer 64753 346005 33710 0 3 0x4000082 thrsleep syz-fuzzer 64753 26975 33710 0 3 0x4000082 thrsleep syz-fuzzer 64753 518415 33710 0 3 0x4000082 thrsleep syz-fuzzer 64753 216435 33710 0 3 0x4000082 kqread syz-fuzzer 64753 244411 33710 0 3 0x4000082 thrsleep syz-fuzzer 64753 294736 33710 0 3 0x4000082 thrsleep syz-fuzzer 33710 216702 27082 0 3 0x10008a pause ksh 27082 426955 11582 0 3 0x92 select sshd 36906 262669 1 0 3 0x100083 ttyin getty 11582 175509 1 0 3 0x80 select sshd 22667 139778 1235 73 3 0x100010 ffs_fsync syslogd 1235 128082 1 0 3 0x100082 netio syslogd 17423 8258 1 77 3 0x100090 poll dhclient 25385 403820 1 0 3 0x80 poll dhclient 47785 110959 0 0 2 0x14200 zerothread 61055 474140 0 0 3 0x14200 aiodoned aiodoned 46499 512546 0 0 3 0x14200 syncer update 3160 437132 0 0 3 0x14200 cleaner cleaner 56048 488813 0 0 2 0x14200 reaper 97030 504346 0 0 3 0x14200 pgdaemon pagedaemon 66709 85999 0 0 3 0x14200 bored crynlk 96124 231078 0 0 3 0x14200 bored crypto 47486 79353 0 0 3 0x40014200 acpi0 acpi0 29236 468553 0 0 3 0x40014200 idle1 85072 410577 0 0 3 0x14200 bored softnet 20975 202488 0 0 3 0x14200 bored systqmp 91678 192874 0 0 3 0x14200 bored systq 86651 389350 0 0 3 0x40014200 bored softclock 47333 97165 0 0 7 0x40014200 idle0 1 381475 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper