panic: witness_warn Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *481291 95567 0 0 0x4000000 1 syz-executor7038 59723 17099 0 0 0x480 0 syz-executor7038 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(81f79b33cdaa2370,0,ffff800020be4010) at witness_warn+0x6e0 witness_debugger sys/kern/subr_witness.c:2546 [inline] witness_warn(81f79b33cdaa2370,0,ffff800020be4010) at witness_warn+0x6e0 sys/kern/subr_witness.c:1462 userret(1bfc2da9ada39d3) at userret+0x361 sys/kern/kern_sig.c:1899 syscall(9050693ec4aa6ae2) at syscall+0x680 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(9050693ec4aa6ae2) at syscall+0x680 sys/arch/amd64/amd64/trap.c:605 Xsyscall(6,5,d337b5bf0c8,0,d337b5bf0a8,d337b5bf0a0) at Xsyscall+0x128 end of kernel end trace frame: 0xd35bbe9e250, 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(81f79b33cdaa2370,0,ffff800020be4010) at witness_warn+0x6e0 witness_debugger sys/kern/subr_witness.c:2546 [inline] witness_warn(81f79b33cdaa2370,0,ffff800020be4010) at witness_warn+0x6e0 sys/kern/subr_witness.c:1462 userret(1bfc2da9ada39d3) at userret+0x361 sys/kern/kern_sig.c:1899 syscall(9050693ec4aa6ae2) at syscall+0x680 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(9050693ec4aa6ae2) at syscall+0x680 sys/arch/amd64/amd64/trap.c:605 Xsyscall(6,5,d337b5bf0c8,0,d337b5bf0a8,d337b5bf0a0) at Xsyscall+0x128 end of kernel end trace frame: 0xd35bbe9e250, count: -6 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff800020c17420 rbx 0xffff800020c174c0 rdx 0xffffffff81ec7fae cmd0646_9_tim_udma+0x14d39 rcx 0x201 rax 0x1 r8 0xffffffff81ba5254 kprintf+0x174 r9 0x1 r10 0xaaffac73f45a8dcc r11 0x3dbb57dc8bf3f35e r12 0x3000000008 r13 0xffff800020c17430 r14 0x100 r15 0x1 rip 0xffffffff817aed68 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020c17410 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor7038) pid=481291 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800020be52d0,0xffff800020be4278 process=0xffff800020b5b3b8 user=0xffff800020c12000, vmspace=0xfffffd806e926b48 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 89725 214206 54088 0 2 0x480 syz-executor7038 89725 316849 54088 0 3 0x4000080 fsleep syz-executor7038 89725 486760 54088 0 3 0x4000080 fsleep syz-executor7038 89725 302636 54088 0 3 0x4000080 fsleep syz-executor7038 95567 465868 17099 0 2 0x480 syz-executor7038 *95567 481291 17099 0 7 0x4000000 syz-executor7038 95567 205148 17099 0 3 0x4000080 fsleep syz-executor7038 95567 511450 17099 0 3 0x4000080 fsleep syz-executor7038 17099 59723 40524 0 7 0x480 syz-executor7038 54088 425072 40524 0 3 0x80 nanosleep syz-executor7038 40524 161525 68064 0 3 0x82 nanosleep syz-executor7038 68064 470302 47027 0 3 0x10008a pause ksh 47027 436661 84331 0 3 0x92 select sshd 76749 432849 1 0 3 0x100083 ttyin getty 84331 74446 1 0 3 0x80 select sshd 88372 105675 90966 73 3 0x100010 ffs_fsync syslogd 90966 499849 1 0 3 0x100082 netio syslogd 88289 67195 1 77 3 0x100090 poll dhclient 60143 492744 1 0 3 0x80 poll dhclient 10721 115300 0 0 3 0x14200 pgzero zerothread 96706 96821 0 0 3 0x14200 aiodoned aiodoned 64274 249592 0 0 3 0x14200 syncer update 8961 473051 0 0 3 0x14200 cleaner cleaner 54997 428744 0 0 3 0x14200 reaper reaper 26141 39159 0 0 3 0x14200 pgdaemon pagedaemon 6620 206485 0 0 3 0x14200 bored crynlk 62537 372329 0 0 3 0x14200 bored crypto 43884 372509 0 0 3 0x40014200 acpi0 acpi0 62850 365876 0 0 3 0x40014200 idle1 49850 416449 0 0 3 0x14200 bored softnet 36340 16409 0 0 3 0x14200 bored systqmp 67116 243476 0 0 3 0x14200 bored systq 24412 109081 0 0 3 0x40014200 bored softclock 54352 520107 0 0 3 0x40014200 idle0 1 84678 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper