witness: lock order reversal: 1st 0xffffffff8290fe50 netlock (netlock) 2nd 0xfffffd807ea18310 vmmaplk (&map->lock) lock order "&map->lock"(rwlock) -> "netlock"(rwlock) first seen at: #0 rw_enter_write+0x5b sys/kern/kern_rwlock.c:128 #1 udp_sysctl+0x8a sys/netinet/udp_usrreq.c:1269 #2 sys_sysctl+0x209 sys/kern/kern_sysctl.c:249 #3 syscall+0x489 mi_syscall sys/sys/syscall_mi.h:102 [inline] #3 syscall+0x489 sys/arch/amd64/amd64/trap.c:585 #4 Xsyscall+0x128 lock order "netlock"(rwlock) -> "&map->lock"(rwlock) first seen at: #0 rw_enter_read+0x66 sys/kern/kern_rwlock.c:112 #1 uvmfault_lookup+0xd9 sys/uvm/uvm_fault.c:1758 #2 uvm_fault_check+0x3a sys/uvm/uvm_fault.c:674 #3 uvm_fault+0x102 sys/uvm/uvm_fault.c:602 #4 kpageflttrap+0x209 #5 kerntrap+0xef sys/arch/amd64/amd64/trap.c:318 #6 alltraps_kern_meltdown+0x7b #7 copyout+0x53 #8 ifioctl_get+0x2dd #9 soo_ioctl+0x26c #10 fifo_ioctl+0x104 sys/miscfs/fifofs/fifo_vnops.c:307 #11 VOP_IOCTL+0x96 sys/kern/vfs_vops.c:264 #12 vn_ioctl+0xbc sys/kern/vfs_vnops.c:531 #13 sys_ioctl+0x4a2 #14 syscall+0x489 mi_syscall sys/sys/syscall_mi.h:102 [inline] #14 syscall+0x489 sys/arch/amd64/amd64/trap.c:585 #15 Xsyscall+0x128 Stopped at db_enter+0x18: addq $0x8,%rsp ddb{0}> ddb{0}> set $lines = 0 ddb{0}> set $maxwidth = 0 ddb{0}> show panic the kernel did not panic ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:440 witness_checkorder(fffffd807ea18310,1,0) at witness_checkorder+0x10b7 witness_debugger sys/kern/subr_witness.c:2502 [inline] witness_checkorder(fffffd807ea18310,1,0) at witness_checkorder+0x10b7 sys/kern/subr_witness.c:1105 rw_enter_read(fffffd807ea18300) at rw_enter_read+0x66 sys/kern/kern_rwlock.c:112 uvmfault_lookup(ffff80002508a0a0,0) at uvmfault_lookup+0xd9 sys/uvm/uvm_fault.c:1758 uvm_fault_check(ffff80002508a0a0,ffff80002508a0d8,ffff80002508a100) at uvm_fault_check+0x3a sys/uvm/uvm_fault.c:674 uvm_fault(fffffd807ea182f8,2000c000,0,2) at uvm_fault+0x102 sys/uvm/uvm_fault.c:602 kpageflttrap(ffff80002508a230,2000cf4f) at kpageflttrap+0x209 kerntrap(ffff80002508a230) at kerntrap+0xef sys/arch/amd64/amd64/trap.c:318 alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b copyout() at copyout+0x53 ifioctl_get(c0106924,ffff80002508a780) at ifioctl_get+0x2dd soo_ioctl(ffff80002508a4e0,c0106924,ffff80002508a780,ffff8000246787e8) at soo_ioctl+0x26c fifo_ioctl(ffff80002508a5c8) at fifo_ioctl+0x104 sys/miscfs/fifofs/fifo_vnops.c:307 VOP_IOCTL(fffffd8078ec9420,c0106924,ffff80002508a780,3,fffffd807f7d8000,ffff8000246787e8) at VOP_IOCTL+0x96 sys/kern/vfs_vops.c:264 vn_ioctl(fffffd807b5474e0,c0106924,ffff80002508a780,ffff8000246787e8) at vn_ioctl+0xbc sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000246787e8,ffff80002508a898,ffff80002508a8f0) at sys_ioctl+0x4a2 syscall(ffff80002508a960) at syscall+0x489 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff80002508a960) at syscall+0x489 sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xdc55476b320, count: -18 ddb{0}> show registers rdi 0x3 rsi 0x40000 acpi_pdirpa+0x2be68 rbp 0xffff800025089d90 rbx 0x3 rdx 0xffff800000bd2240 rcx 0 rax 0x3ffff acpi_pdirpa+0x2be67 r8 0xffff800025089d00 r9 0x8080808080808080 r10 0xed0541bae307b32f r11 0x859a24f58d4286dd r12 0xffffffff82ab0010 w_lodata+0x526a0 r13 0 r14 0xffffffff82aaa600 w_lodata+0x4cc90 r15 0xfffffd8002f62d80 rip 0xffffffff8138d658 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800025089d80 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.4) pid=436829 stat=onproc flags process=10 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800024678fc8,0xffff8000246797b8 process=0xffff8000274ae9b0 user=0xffff800025085000, vmspace=0xfffffd807ea182f8 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 42765 152072 88733 32767 7 0x10 syz-executor.7 22317 235189 94339 32767 2 0x10 syz-executor.6 22317 204532 94339 32767 3 0x4000090 fsleep syz-executor.6 68765 330730 77634 32767 2 0x10 syz-executor.3 68765 107408 77634 32767 3 0x4000090 netcon2 syz-executor.3 68765 32642 77634 32767 3 0x4000090 kqread syz-executor.3 75410 306930 84934 32767 2 0x10 syz-executor.4 *75410 436829 84934 32767 7 0x4000010 syz-executor.4 23607 510882 62985 32767 3 0x90 nanoslp syz-executor.1 23607 53975 62985 32767 3 0x4000090 kqsel syz-executor.1 32166 516815 0 0 3 0x14200 bored sosplice 94339 395639 7945 32767 3 0x90 nanoslp syz-executor.6 84934 200233 98768 32767 3 0x90 nanoslp syz-executor.4 77634 100747 29119 32767 3 0x90 nanoslp syz-executor.3 88733 115965 50199 32767 3 0x90 nanoslp syz-executor.7 50199 233755 32156 0 3 0x82 wait syz-executor.7 7945 380697 32156 0 3 0x82 wait syz-executor.6 90276 94399 43304 32767 3 0x90 nanoslp syz-executor.5 98768 389877 32156 0 3 0x82 wait syz-executor.4 43304 429304 32156 0 3 0x82 wait syz-executor.5 10017 206537 53633 32767 3 0x90 nanoslp syz-executor.2 29119 121203 32156 0 3 0x82 wait syz-executor.3 60612 109203 74687 32767 3 0x10 biowait syz-executor.0 62985 49879 41936 32767 3 0x90 nanoslp syz-executor.1 53633 317213 32156 0 3 0x82 wait syz-executor.2 41936 194745 32156 0 3 0x82 wait syz-executor.1 74687 22518 32156 0 3 0x82 wait syz-executor.0 32156 188097 77088 0 3 0x82 thrsleep syz-fuzzer 32156 52437 77088 0 3 0x4000082 nanoslp syz-fuzzer 32156 435232 77088 0 3 0x4000082 thrsleep syz-fuzzer 32156 281892 77088 0 3 0x4000082 thrsleep syz-fuzzer 32156 354174 77088 0 3 0x4000082 nanoslp syz-fuzzer 32156 452017 77088 0 3 0x4000082 thrsleep syz-fuzzer 32156 163862 77088 0 3 0x4000082 thrsleep syz-fuzzer 32156 255287 77088 0 3 0x4000082 thrsleep syz-fuzzer 77088 300560 15915 0 3 0x10008a sigsusp ksh 15915 166675 99460 0 3 0x9a kqread sshd 36453 450241 1 0 3 0x100083 ttyin getty 99460 238279 1 0 3 0x88 kqread sshd 88544 295992 19127 73 3 0x1100090 kqread syslogd 19127 112030 1 0 3 0x100082 netio syslogd 51224 213577 1 0 3 0x100080 kqread resolvd 48436 447761 11381 77 3 0x100092 kqread dhcpleased 43928 455560 11381 77 3 0x100092 kqread dhcpleased 11381 165318 1 0 3 0x80 kqread dhcpleased 61256 313925 0 0 3 0x14200 bored smr 82713 386528 0 0 2 0x14200 zerothread 23301 258684 0 0 3 0x14200 aiodoned aiodoned 5467 89493 0 0 3 0x14200 syncer update 31651 506264 0 0 3 0x14200 cleaner cleaner 65434 112757 0 0 3 0x14200 reaper reaper 48501 519395 0 0 3 0x14200 pgdaemon pagedaemon 90614 234608 0 0 3 0x14200 bored viomb 64473 254701 0 0 3 0x40014200 acpi0 acpi0 91973 380653 0 0 3 0x40014200 idle1 36030 149066 0 0 3 0x14200 bored softnet 93891 395484 0 0 3 0x14200 bored systqmp 46223 491939 0 0 3 0x14200 bored systq 99966 359067 0 0 3 0x40014200 bored softclock 89647 118018 0 0 3 0x40014200 idle0 1 393087 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 75410 (syz-executor.4) thread 0xffff8000246787e8 (436829) shared rwlock netlock r = 0 (0xffffffff8290fe50) #0 witness_lock+0x44d #1 ifioctl_get+0x2d5 sys/net/if.c:2319 #2 soo_ioctl+0x26c #3 fifo_ioctl+0x104 sys/miscfs/fifofs/fifo_vnops.c:307 #4 VOP_IOCTL+0x96 sys/kern/vfs_vops.c:264 #5 vn_ioctl+0xbc sys/kern/vfs_vnops.c:531 #6 sys_ioctl+0x4a2 #7 syscall+0x489 mi_syscall sys/sys/syscall_mi.h:102 [inline] #7 syscall+0x489 sys/arch/amd64/amd64/trap.c:585 #8 Xsyscall+0x128 exclusive kernel_lock &kernel_lock r = 1 (0xffffffff829de988) #0 witness_lock+0x44d #1 vn_ioctl+0x41 sys/kern/vfs_vnops.c:514 #2 sys_ioctl+0x4a2 #3 syscall+0x489 mi_syscall sys/sys/syscall_mi.h:102 [inline] #3 syscall+0x489 sys/arch/amd64/amd64/trap.c:585 #4 Xsyscall+0x128 Process 60612 (syz-executor.0) thread 0xffff8000ffff4540 (109203) exclusive rrwlock inode r = 0 (0xfffffd807ea684e8) #0 witness_lock+0x44d #1 rw_enter+0x3e1 sys/kern/kern_rwlock.c:310 #2 rrw_enter+0x8b sys/kern/kern_rwlock.c:461 #3 VOP_LOCK+0x87 sys/kern/vfs_vops.c:534 #4 ufs_ihashins+0x42 sys/ufs/ufs/ufs_ihash.c:140 #5 ffs_vget+0x141 sys/ufs/ffs/ffs_vfsops.c:1347 #6 ffs_inode_alloc+0x1be sys/ufs/ffs/ffs_alloc.c:394 #7 ufs_mkdir+0xf4 sys/ufs/ufs/ufs_vnops.c:1162 #8 VOP_MKDIR+0xbf sys/kern/vfs_vops.c:404 #9 domkdirat+0x121 sys/kern/vfs_syscalls.c:3101 #10 syscall+0x489 mi_syscall sys/sys/syscall_mi.h:102 [inline] #10 syscall+0x489 sys/arch/amd64/amd64/trap.c:585 #11 Xsyscall+0x128 exclusive rrwlock inode r = 0 (0xfffffd806ad6b0a8) #0 witness_lock+0x44d #1 rw_enter+0x3e1 sys/kern/kern_rwlock.c:310 #2 rrw_enter+0x8b sys/kern/kern_rwlock.c:461 #3 VOP_LOCK+0x87 sys/kern/vfs_vops.c:534 #4 vn_lock+0x84 sys/kern/vfs_vnops.c:579 #5 vfs_lookup+0xd1 sys/kern/vfs_lookup.c:413 #6 namei+0x36a sys/kern/vfs_lookup.c:245 #7 domkdirat+0x75 sys/kern/vfs_syscalls.c:3086 #8 syscall+0x489 mi_syscall sys/sys/syscall_mi.h:102 [inline] #8 syscall+0x489 sys/arch/amd64/amd64/trap.c:585 #9 Xsyscall+0x128 ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10172 6407K 6419K 78643K 11262 0 pcb 13 8K 8K 78643K 13 0 rtable 244 7K 7K 78643K 357 0 ifaddr 81 16K 16K 78643K 82 0 sysctl 2 0K 0K 78643K 2 0 counters 56 35K 35K 78643K 56 0 ioctlops 0 0K 2K 78643K 33 0 iov 0 0K 16K 78643K 10 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 5 0 vnodes 1271 79K 79K 78643K 1295 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 4 0 VM map 2 1K 1K 78643K 2 0 sem 10 1K 1K 78643K 10 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12548 0 file desc 23 85K 121K 78643K 426 0 sigio 0 0K 0K 78643K 2 0 proc 56 74K 99K 78643K 464 0 subproc 104 6K 6K 78643K 104 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 19 0 in_multi 99 6K 6K 78643K 99 0 ether_multi 1 0K 0K 78643K 1 0 mrt 1 0K 0K 78643K 1 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 49 228K 228K 78643K 49 0 exec 0 0K 2K 78643K 609 0 tdb 3 0K 0K 78643K 3 0 pagedep 1 8K 8K 78643K 1 0 inodedep 1 32K 32K 78643K 1 0 newblk 1 0K 0K 78643K 1 0 VM swap 7 26K 26K 78643K 7 0 UVM amap 305 82K 91K 78643K 6427 0 UVM aobj 5 2K 2K 78643K 5 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 12 0 NDP 11 0K 2K 78643K 27 0 temp 93 4695K 4759K 78643K 4719 0 kqueue 13 20K 22K 78643K 34 0 SYN cache 2 16K 16K 78643K 2 0 ddb{0}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle plcache 128 22 0 0 1 0 1 1 0 8 0 rtpcb 120 39 0 36 1 0 1 1 0 8 0 rtentry 112 114 0 1 4 0 4 4 0 8 0 unpcb 136 95 0 80 1 0 1 1 0 8 0 syncache 296 14 0 14 2 1 1 1 0 8 1 tcpqe 32 661 0 661 2 1 1 2 0 8 1 tcpcb 736 91 0 77 3 0 3 3 0 8 1 arp 120 18 0 0 1 0 1 1 0 8 0 inpcb 304 177 0 165 2 0 2 2 0 8 0 rttmr 72 1 0 0 1 0 1 1 0 8 0 nd6 48 26 0 0 1 0 1 1 0 8 0 kcovpl 48 8 0 0 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 499 0 0 32 0 32 32 0 8 0 art_table 32 500 0 0 5 0 5 5 0 8 0 art_node 16 113 0 10 1 0 1 1 0 8 0 sysvmsgpl 40 6 0 4 1 0 1 1 0 8 0 semupl 112 4 0 4 1 0 1 1 0 8 1 semapl 112 8 0 0 1 0 1 1 0 8 0 shmpl 112 2 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1805 0 375 90 0 90 90 0 8 0 ffsino 272 1805 0 375 96 0 96 96 0 8 0 nchpl 144 2378 0 716 62 0 62 62 0 8 0 uvmvnodes 80 1918 0 0 40 0 40 40 0 8 0 vnodes 224 1918 0 0 113 0 113 113 0 8 0 namei 1024 7271 0 7270 2 1 1 2 0 8 0 percpumem 16 40 0 0 1 0 1 1 0 8 0 scxspl 216 7427 0 7426 9 1 8 8 0 8 7 plimitpl 152 38 0 16 1 0 1 1 0 8 0 sigapl 424 700 0 649 7 0 7 7 0 8 1 futexpl 64 1425 0 1424 1 0 1 1 0 8 0 knotepl 120 129 0 0 4 0 4 4 0 8 0 kqueuepl 216 55 0 44 1 0 1 1 0 8 0 pipepl 336 134 0 106 4 1 3 3 0 8 0 fdescpl 496 685 0 651 7 1 6 6 0 8 1 filepl 152 2183 0 1946 10 0 10 10 0 8 0 lockfpl 104 29 0 27 1 0 1 1 0 8 0 lockfspl 48 14 0 12 1 0 1 1 0 8 0 sessionpl 144 23 0 7 1 0 1 1 0 8 0 pgrppl 48 23 0 7 1 0 1 1 0 8 0 ucredpl 96 229 0 211 1 0 1 1 0 8 0 zombiepl 144 651 0 649 1 0 1 1 0 8 0 processpl 1064 700 0 649 5 1 4 4 0 8 0 procpl 672 1026 0 963 6 0 6 6 0 8 0 sosppl 168 6 0 3 1 0 1 1 0 8 0 sockpl 480 312 0 282 4 0 4 4 0 8 0 mcl16k 16384 1 0 0 1 0 1 1 0 8 0 mcl9k 9216 1 0 0 1 0 1 1 0 8 0 mcl8k 8192 4 0 0 1 0 1 1 0 8 0 mcl4k 4096 3 0 0 1 0 1 1 0 8 0 mcl2k2 2112 2 0 0 1 0 1 1 0 8 0 mcl2k 2048 316 0 0 39 0 39 39 0 8 0 mtagpl 96 3 0 0 1 0 1 1 0 8 0 mbufpl 256 370 0 0 23 0 23 23 0 8 0 bufpl 288 3974 0 139 274 0 274 274 0 8 0 anonpl 24 145197 0 133192 86 0 86 86 0 186 3 amapchunkpl 152 14923 0 14190 36 1 35 35 0 158 4 amappl16 200 1111 0 833 19 1 18 18 0 8 2 amappl15 192 170 0 163 1 0 1 1 0 8 0 amappl14 184 61 0 54 1 0 1 1 0 8 0 amappl13 176 116 0 110 1 0 1 1 0 8 0 amappl12 168 11 0 9 2 1 1 1 0 8 0 amappl11 160 46 0 33 1 0 1 1 0 8 0 amappl10 152 160 0 150 1 0 1 1 0 8 0 amappl9 144 441 0 437 1 0 1 1 0 8 0 amappl8 136 634 0 579 2 0 2 2 0 8 0 amappl7 128 193 0 179 1 0 1 1 0 8 0 amappl6 120 196 0 178 2 1 1 2 0 8 0 amappl5 112 630 0 605 1 0 1 1 0 8 0 amappl4 104 804 0 775 2 1 1 2 0 8 0 amappl3 96 171 0 160 1 0 1 1 0 8 0 amappl2 88 539 0 495 3 1 2 3 0 8 0 amappl1 80 14858 0 14242 18 3 15 18 0 8 1 amappl 88 6002 0 5757 7 0 7 7 0 92 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma1024 1024 1 0 0 1 0 1 1 0 8 0 dma256 256 6 0 6 1 1 0 1 0 8 0 dma128 128 253 0 253 1 1 0 1 0 8 0 dma64 64 6 0 6 1 1 0 1 0 8 0 dma32 32 7 0 7 1 1 0 1 0 8 0 dma16 16 18 0 17 1 0 1 1 0 8 0 aobjpl 72 4 0 0 1 0 1 1 0 8 0 uaddrrnd 24 685 0 651 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 685 0 651 1 0 1 1 0 8 0 vmmpekpl 168 9047 0 9003 3 0 3 3 0 8 0 vmmpepl 168 64013 0 61604 116 0 116 116 0 357 3 vmsppl 368 684 0 651 4 0 4 4 0 8 0 rwobjpl 56 17744 0 14629 46 1 45 45 0 8 0 pdppl 4096 1377 0 1302 111 30 81 93 0 8 6 pvpl 32 379860 0 362902 242 7 235 242 0 265 88 pmappl 248 684 0 651 4 1 3 3 0 8 0 extentpl 40 58 0 38 1 0 1 1 0 8 0 phpool 112 688 0 34 19 0 19 19 0 8 0 ddb{0}> machine ddbcpu 0 Invalid cpu 0 ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:440 witness_checkorder(fffffd807ea18310,1,0) at witness_checkorder+0x10b7 witness_debugger sys/kern/subr_witness.c:2502 [inline] witness_checkorder(fffffd807ea18310,1,0) at witness_checkorder+0x10b7 sys/kern/subr_witness.c:1105 rw_enter_read(fffffd807ea18300) at rw_enter_read+0x66 sys/kern/kern_rwlock.c:112 uvmfault_lookup(ffff80002508a0a0,0) at uvmfault_lookup+0xd9 sys/uvm/uvm_fault.c:1758 uvm_fault_check(ffff80002508a0a0,ffff80002508a0d8,ffff80002508a100) at uvm_fault_check+0x3a sys/uvm/uvm_fault.c:674 uvm_fault(fffffd807ea182f8,2000c000,0,2) at uvm_fault+0x102 sys/uvm/uvm_fault.c:602 kpageflttrap(ffff80002508a230,2000cf4f) at kpageflttrap+0x209 kerntrap(ffff80002508a230) at kerntrap+0xef sys/arch/amd64/amd64/trap.c:318 alltraps_kern_meltdown() at alltraps_kern_meltdown+0x7b copyout() at copyout+0x53 ifioctl_get(c0106924,ffff80002508a780) at ifioctl_get+0x2dd soo_ioctl(ffff80002508a4e0,c0106924,ffff80002508a780,ffff8000246787e8) at soo_ioctl+0x26c fifo_ioctl(ffff80002508a5c8) at fifo_ioctl+0x104 sys/miscfs/fifofs/fifo_vnops.c:307 VOP_IOCTL(fffffd8078ec9420,c0106924,ffff80002508a780,3,fffffd807f7d8000,ffff8000246787e8) at VOP_IOCTL+0x96 sys/kern/vfs_vops.c:264 vn_ioctl(fffffd807b5474e0,c0106924,ffff80002508a780,ffff8000246787e8) at vn_ioctl+0xbc sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000246787e8,ffff80002508a898,ffff80002508a8f0) at sys_ioctl+0x4a2 syscall(ffff80002508a960) at syscall+0x489 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff80002508a960) at syscall+0x489 sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xdc55476b320, count: -18 ddb{0}> machine ddbcpu 1 Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp ddb{1}> trace x86_ipi_db(ffff800020ce8ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:393 x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23 __mp_lock(ffffffff829de780) at __mp_lock+0x122 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff829de780) at __mp_lock+0x122 sys/kern/kern_lock.c:147 syscall(ffff80002b347f60) at syscall+0x3ef mi_syscall sys/sys/syscall_mi.h:93 [inline] syscall(ffff80002b347f60) at syscall+0x3ef sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe76c0, count: -6