witness: lock order reversal: 1st 0xffff80000128fbd0 sbufrcv (&so->so_rcv.sb_lock) 2nd 0xfffffd806de8ccc0 inode (&ip->i_lock) lock order [1] sbufrcv (&so->so_rcv.sb_lock) -> [2] inode (&ip->i_lock) lock order data 0xffffffff831566ce -> 0xffffffff830cf67f is missing lock order [2] inode (&ip->i_lock) -> [1] sbufrcv (&so->so_rcv.sb_lock) #0 rw_do_enter_write+0xb7 sys/kern/kern_rwlock.c:233 #1 sblock+0xb7 sys/kern/uipc_socket2.c:537 #2 soreceive+0x28e sys/kern/uipc_socket.c:876 #3 fifo_read+0x11a sys/miscfs/fifofs/fifo_vnops.c:264 #4 VOP_READ+0x102 sys/kern/vfs_vops.c:227 #5 vn_rdwr+0x15b #6 vndsetcred+0xa1 sys/dev/vnd.c:684 #7 vndioctl+0xe6c sys/dev/vnd.c:485 #8 VOP_IOCTL+0xac sys/kern/vfs_vops.c:264 #9 vn_ioctl+0xf8 sys/kern/vfs_vnops.c:531 #10 sys_ioctl+0x5c3 #11 syscall+0xbc6 mi_syscall sys/sys/syscall_mi.h:176 [inline] #11 syscall+0xbc6 sys/arch/amd64/amd64/trap.c:577 #12 Xsyscall+0x128 Stopped at db_enter+0x25: 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+0x25 sys/arch/amd64/amd64/db_interface.c:437 witness_checkorder(fffffd806de8ccc0,9,0) at witness_checkorder+0x1047 rw_do_enter_write(fffffd806de8cca8,1) at rw_do_enter_write+0xb7 sys/kern/kern_rwlock.c:233 rrw_enter(fffffd806de8cca8,1) at rrw_enter+0xc6 sys/kern/kern_rwlock.c:616 VOP_LOCK(fffffd805ffc5870,2001) at VOP_LOCK+0xa6 sys/kern/vfs_vops.c:524 vn_lock(fffffd805ffc5870,2001) at vn_lock+0xa4 sys/kern/vfs_vnops.c:570 vfs_getcwd_common(fffffd805ffc5870,fffffd805ffc5870,0,0,200,0,55e81600abbb397b) at vfs_getcwd_common+0xd1 sys/kern/vfs_getcwd.c:287 vn_isunder(fffffd805ffc5870,fffffd805ffc5870,ffff80003c64e548) at vn_isunder+0x56 sys/kern/vfs_vnops.c:694 unp_externalize(fffffd8078909900,ec,0) at unp_externalize+0x286 sys/kern/uipc_usrreq.c:1086 soreceive(ffff80000128faf0,ffff800030156b28,ffff800030156ad8,0,ffff800030156b18,ffff800030156c9c,2d85b3409aca3509) at soreceive+0xc73 sys/kern/uipc_socket.c:1015 recvit(ffff80003c64e548,5,ffff800030156c70,0,ffff800030156d20) at recvit+0x40a sys/kern/uipc_syscalls.c:1072 sys_recvmsg(ffff80003c64e548,ffff800030156dd0,ffff800030156d20) at sys_recvmsg+0x1bf sys/kern/uipc_syscalls.c:872 syscall(ffff800030156dd0) at syscall+0xbc6 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff800030156dd0) at syscall+0xbc6 sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x191067da330, count: -14 ddb{0}> show registers rdi 0 rsi 0x80000 acpi_pdirpa+0x6be71 rbp 0xffff8000301565b0 rbx 0xfffffd800433dfa8 rdx 0xffff80000128dc80 rcx 0xffff80003c64e548 rax 0x7ffff acpi_pdirpa+0x6be70 r8 0xffff800030156490 r9 0x8080808080808080 r10 0x4a3863e5e6947ec6 r11 0x5efb706bb06c53f1 r12 0 r13 0xfffffd8003b56f00 r14 0x3 r15 0xffffffff rip 0xffffffff82a6fbd5 db_enter+0x25 cs 0x8 rflags 0x246 rsp 0xffff8000301565a0 ss 0x10 db_enter+0x25: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor) tid=466903 pid=51973 tcnt=3 stat=onproc flags process=1000000 proc=4000000 runpri=24, usrpri=75, slppri=24, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff80003c64f478,0xffff8000ffff8540 process=0xffff80003c62b490 user=0xffff800030151000, vmspace=0xfffffd806736cca8 estcpu=36, cpticks=0, pctcpu=0.0, user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 99132 221462 7242 0 2 0 syz-executor 94819 271629 75478 0 2 0 syz-executor 94819 454885 75478 0 7 0x4000000 syz-executor 65194 157245 98272 0 2 0 syz-executor 65194 358402 98272 0 3 0x4000080 fsleep syz-executor 65194 86636 98272 0 3 0x4000080 fsleep syz-executor 70505 21817 87538 0 3 0x80 nanoslp syz-executor 70505 247167 87538 0 3 0x4000080 fsleep syz-executor 70505 79869 87538 0 3 0x4000080 fsleep syz-executor 51973 42316 32371 0 2 0x1000000 syz-executor *51973 466903 32371 0 7 0x5000000 syz-executor 51973 283931 32371 0 2 0x5000000 syz-executor 14214 132110 67189 0 3 0x80 nanoslp syz-executor 14214 86243 67189 0 3 0x4000080 fsleep syz-executor 14214 333928 67189 0 3 0x4000080 fsleep syz-executor 91950 487846 39068 0 3 0x80 nanoslp syz-executor 91950 140870 39068 0 3 0x4000080 ttyin syz-executor 673 379947 90779 0 3 0x80 nanoslp syz-executor 673 496374 90779 0 3 0x4000080 fsleep syz-executor 673 108245 90779 0 3 0x4000080 fsleep syz-executor 673 101399 90779 0 3 0x4000080 lockf syz-executor 39068 261733 2142 0 3 0x82 nanoslp syz-executor 80329 79718 1 0 3 0x100083 ttyin getty 62160 408389 0 0 3 0x14200 acct acct 30394 36247 0 0 3 0x14200 bored sosplice 86545 79069 0 0 3 0x14280 nfsidl nfsio 48670 486446 0 0 3 0x14280 nfsidl nfsio 62599 375208 0 0 3 0x14280 nfsidl nfsio 30410 150510 0 0 3 0x14280 nfsidl nfsio 77736 191937 0 0 3 0x14280 nfsidl nfsio 76364 106164 0 0 3 0x14280 nfsidl nfsio 22058 309007 0 0 3 0x14280 nfsidl nfsio 55644 468444 0 0 3 0x14280 nfsidl nfsio 20928 297499 0 0 3 0x14280 nfsidl nfsio 20235 250836 0 0 3 0x14280 nfsidl nfsio 64995 471743 0 0 3 0x14280 nfsidl nfsio 26748 197048 0 0 3 0x14280 nfsidl nfsio 43477 166372 0 0 3 0x14280 nfsidl nfsio 18878 297585 0 0 3 0x14280 nfsidl nfsio 95297 51059 0 0 3 0x14280 nfsidl nfsio 39614 217099 0 0 3 0x14280 nfsidl nfsio 48 319851 0 0 3 0x14280 nfsidl nfsio 83430 472061 0 0 3 0x14280 nfsidl nfsio 45691 155147 0 0 3 0x14280 nfsidl nfsio 59360 475621 0 0 3 0x14280 nfsidl nfsio 98272 143694 2142 0 3 0x82 nanoslp syz-executor 87538 389652 2142 0 3 0x82 nanoslp syz-executor 7242 361413 2142 0 3 0x82 nanoslp syz-executor 75478 95251 2142 0 3 0x82 nanoslp syz-executor 67189 433633 2142 0 3 0x82 nanoslp syz-executor 90779 328331 2142 0 3 0x82 nanoslp syz-executor 32371 291776 2142 0 3 0x82 nanoslp syz-executor 2142 296788 99081 0 3 0x82 kqread syz-executor 99081 279358 19946 0 3 0x10008a sigsusp ksh 19946 508812 54025 0 3 0x98 kqread sshd-session 54025 358248 2885 0 3 0x92 kqread sshd-session 2885 67504 1 0 3 0x88 kqread sshd 70158 377960 54033 74 3 0x1100092 bpf pflogd 54033 338096 1 0 3 0x80 sbwait pflogd 58672 36797 48843 73 3 0x1100090 kqread syslogd 48843 123226 1 0 3 0x100082 sbwait syslogd 88997 476691 1 0 3 0x100080 kqread resolvd 90732 30734 10419 77 3 0x100092 kqread dhcpleased 73861 356407 10419 77 3 0x100092 kqread dhcpleased 10419 75201 1 0 3 0x80 kqread dhcpleased 64654 445799 0 0 3 0x14200 bored smr 24162 63607 0 0 2 0x14200 zerothread 28062 50392 0 0 3 0x14200 aiodoned aiodoned 55269 306237 0 0 3 0x14200 syncer update 19690 518884 0 0 3 0x14200 cleaner cleaner 35939 185280 0 0 3 0x14200 reaper reaper 12410 224185 0 0 3 0x14200 pgdaemon pagedaemon 20775 257035 0 0 3 0x14200 bored viomb 7402 132374 0 0 3 0x40014200 acpi0 acpi0 52815 93334 0 0 3 0x40014200 idle1 53748 521683 0 0 3 0x14200 bored softnet3 13285 156313 0 0 3 0x14200 bored softnet2 14606 421236 0 0 3 0x14200 bored softnet1 27406 491309 0 0 3 0x14200 bored softnet0 71460 463531 0 0 3 0x14200 bored systqmp 32110 68366 0 0 3 0x14200 bored systq 84733 195666 0 0 3 0x14200 tmoslp softclockmp 48186 504746 0 0 3 0x40014200 tmoslp softclock 52542 26765 0 0 3 0x40014200 idle0 1 123034 0 0 3 0x80082 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 51973 (syz-executor) thread 0xffff80003c64e548 (466903) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff8360db10) #0 witness_lock+0x5bb stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5bb sys/kern/subr_witness.c:1155 #1 unp_externalize+0x14e #2 soreceive+0xc73 sys/kern/uipc_socket.c:1015 #3 recvit+0x40a sys/kern/uipc_syscalls.c:1072 #4 sys_recvmsg+0x1bf sys/kern/uipc_syscalls.c:872 #5 syscall+0xbc6 mi_syscall sys/sys/syscall_mi.h:176 [inline] #5 syscall+0xbc6 sys/arch/amd64/amd64/trap.c:577 #6 Xsyscall+0x128 exclusive rwlock sbufrcv r = 0 (0xffff80000128fbd0) #0 witness_lock+0x5bb stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5bb sys/kern/subr_witness.c:1155 #1 rw_do_enter_write+0x3ea sys/kern/kern_rwlock.c:316 #2 sblock+0xb7 sys/kern/uipc_socket2.c:537 #3 soreceive+0x28e sys/kern/uipc_socket.c:876 #4 recvit+0x40a sys/kern/uipc_syscalls.c:1072 #5 sys_recvmsg+0x1bf sys/kern/uipc_syscalls.c:872 #6 syscall+0xbc6 mi_syscall sys/sys/syscall_mi.h:176 [inline] #6 syscall+0xbc6 sys/arch/amd64/amd64/trap.c:577 #7 Xsyscall+0x128 ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10214 11052K 11440K 166960K 12618 0 pcb 17 14K 16K 166960K 263 0 rtable 227 8K 8K 166960K 482 0 pf 41 18K 20K 166960K 92 0 ifaddr 45 7K 8K 166960K 72 0 ifgroup 64 2K 2K 166960K 96 0 sysctl 4 1K 2K 166960K 5 0 counters 68 36K 37K 166960K 90 0 ioctlops 0 0K 4K 166960K 1635 0 iov 1 0K 36K 166960K 51 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1391 87K 88K 166960K 2428 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 9K 166960K 26 0 VM map 2 1K 1K 166960K 2 0 sem 21 10K 11K 166960K 49 0 dirhash 12 2K 2K 166960K 30 0 ACPI 1690 195K 286K 166960K 12468 0 file desc 18 65K 93K 166960K 1134 0 sigio 0 0K 0K 166960K 16 0 proc 72 91K 128K 166960K 674 0 subproc 72 4K 4K 166960K 83 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 0 0K 0K 166960K 119 0 in_multi 98 7K 7K 166960K 146 0 ether_multi 1 0K 0K 166960K 4 0 mrt 1 0K 0K 166960K 2 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 103 466K 466K 166960K 103 0 exec 0 0K 1K 166960K 572 0 fusefs mount 1 32K 32K 166960K 1 0 pfkey data 0 0K 0K 166960K 1 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 233 73K 87K 166960K 12202 0 UVM aobj 39 6K 6K 166960K 40 0 pinsyscall 43 86K 104K 166960K 2257 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 0 0K 1K 166960K 100 0 NDP 14 0K 2K 166960K 47 0 temp 71 6898K 7024K 166960K 38445 0 kqueue 14 22K 28K 166960K 204 0 SYN cache 2 16K 16K 166960K 2 0 ddb{0}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle plcache 128 24 0 0 1 0 1 1 0 8 0 rtpcb 120 94 0 91 1 0 1 1 0 8 0 rtentry 112 145 0 43 4 0 4 4 0 8 0 unpcb 144 869 0 848 10 6 4 6 0 8 3 syncache 336 6 0 6 3 3 0 1 0 8 0 tcpqe 32 2 0 2 1 1 0 1 0 8 0 tcpcb 808 364 0 358 12 4 8 8 0 8 7 arp 120 21 0 4 1 0 1 1 0 8 0 inpcb 376 1070 0 1061 11 3 8 8 0 8 7 ip6q 72 1 0 1 1 0 1 1 0 8 1 ip6af 40 2 0 2 1 0 1 1 0 8 1 nd6 136 31 0 3 1 0 1 1 0 8 0 pkpcb 40 4 0 4 3 2 1 1 0 8 1 kcovpl 48 9 0 1 1 0 1 1 0 8 0 ppxss 1168 8 0 8 4 3 1 1 0 8 1 pfstscr 40 1 0 1 1 0 1 1 0 8 1 pffrag 232 8 0 4 1 0 1 1 0 482 0 pffrnode 88 8 0 4 1 0 1 1 0 8 0 pffrent 40 13 0 9 1 0 1 1 0 8 0 pfosfp 40 1428 0 1005 5 0 5 5 0 8 0 pfosfpen 112 1428 0 714 21 0 21 21 0 8 0 pfrktable 1344 1 0 0 1 0 1 1 0 8 0 pftag 88 1 0 0 1 0 1 1 0 8 0 pfstitem 24 73 0 22 1 0 1 1 0 8 0 pfstkey 128 74 0 23 2 0 2 2 0 8 0 pfstate 376 74 0 23 6 0 6 6 0 8 0 pfrule 1344 30 0 23 2 1 1 2 0 8 0 art_heap8 4096 3 0 0 3 0 3 3 0 8 0 art_heap4 256 702 0 218 33 2 31 31 0 8 0 art_table 32 705 0 218 4 0 4 4 0 8 0 art_node 16 141 0 51 1 0 1 1 0 8 0 sysvmsgpl 40 23 0 17 2 1 1 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 42 0 23 1 0 1 1 0 8 0 shmpl 112 37 0 1 2 0 2 2 0 8 0 dirhash 1024 29 0 12 3 0 3 3 0 8 0 dino2pl 256 3582 0 2074 95 0 95 95 0 8 0 ffsino 280 3582 0 2074 109 0 109 109 0 8 0 nchpl 144 5180 0 3486 64 0 64 64 0 8 0 uvmvnodes 80 4234 0 0 87 0 87 87 0 8 0 vnodes 216 4234 0 0 236 0 236 236 0 8 0 namei 1024 17401 0 17401 3 2 1 2 0 8 1 percpumem 16 59 0 11 1 0 1 1 0 8 0 kstatmem 264 50 0 22 4 1 3 3 0 8 1 scsiplug 72 4 0 4 2 1 1 1 0 8 1 scxspl 216 15325 0 15325 10 9 1 8 1 8 1 plimitpl 152 257 0 239 1 0 1 1 0 8 0 sigapl 424 1457 0 1385 9 0 9 9 0 8 0 futexpl 64 15831 0 15823 1 0 1 1 0 8 0 knotepl 120 500 0 0 16 0 16 16 0 8 0 kqueuepl 216 361 0 351 5 4 1 5 0 8 0 pipepl 328 189 0 162 3 0 3 3 0 8 0 fdescpl 504 1416 0 1384 5 0 5 5 0 8 0 filepl 152 9237 0 9011 24 7 17 17 0 8 4 lockfpl 104 447 0 441 1 0 1 1 0 8 0 lockfspl 48 160 0 156 1 0 1 1 0 8 0 sessionpl 144 27 0 18 1 0 1 1 0 8 0 pgrppl 48 49 0 32 1 0 1 1 0 8 0 ucredpl 104 1808 0 1795 1 0 1 1 0 8 0 zombiepl 144 1385 0 1385 2 1 1 1 0 8 1 processpl 1168 1457 0 1385 6 0 6 6 0 8 0 procpl 648 3177 0 3092 8 0 8 8 0 8 0 srpgc 96 4 0 4 2 2 0 1 0 8 0 sosppl 168 6 0 6 3 2 1 1 0 8 1 sockpl 688 2055 0 2022 25 14 11 16 0 8 7 mcl64k 65536 4 0 0 1 0 1 1 0 8 0 mcl16k 16384 1 0 0 1 0 1 1 0 8 0 mcl12k 12288 1 0 0 1 0 1 1 0 8 0 mcl8k 8192 4 0 0 1 0 1 1 0 8 0 mcl4k 4096 111 0 0 14 0 14 14 0 8 0 mcl2k 2048 37 0 0 5 0 5 5 0 8 0 mtagpl 96 41 0 0 1 0 1 1 0 8 0 mbufpl 256 227 0 0 15 0 15 15 0 8 0 bufpl 280 5442 0 146 379 0 379 379 0 8 0 anonpl 24 213724 0 209497 85 46 39 70 0 185 7 amapchunkpl 152 40128 0 39574 49 20 29 38 0 158 3 amappl16 200 4558 0 4519 39 32 7 21 0 8 2 amappl15 192 5 0 5 1 1 0 1 0 8 0 amappl14 184 117 0 105 1 0 1 1 0 8 0 amappl13 176 7 0 7 1 1 0 1 0 8 0 amappl12 168 2136 0 2105 4 1 3 3 0 8 0 amappl11 160 49 0 34 1 0 1 1 0 8 0 amappl10 152 8 0 7 1 0 1 1 0 8 0 amappl9 144 263 0 262 2 1 1 1 0 8 0 amappl8 136 25 0 22 1 0 1 1 0 8 0 amappl7 128 122 0 110 1 0 1 1 0 8 0 amappl6 120 192 0 189 1 0 1 1 0 8 0 amappl5 112 132 0 121 1 0 1 1 0 8 0 amappl4 104 328 0 308 1 0 1 1 0 8 0 amappl3 96 8086 0 7970 4 0 4 4 0 8 0 amappl2 88 692 0 626 2 0 2 2 0 8 0 amappl1 80 11574 0 11005 15 1 14 14 0 8 0 amappl 88 11739 0 11562 5 0 5 5 0 92 0 dma32768 32768 1 0 1 1 1 0 1 0 8 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 128 254 0 254 2 2 0 1 0 8 0 dma64 64 6 0 6 1 1 0 1 0 8 0 dma32 32 8 0 8 2 2 0 1 0 8 0 dma16 16 18 0 17 1 0 1 1 0 8 0 aobjpl 72 39 0 1 1 0 1 1 0 8 0 uaddrrnd 24 1416 0 1384 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 1416 0 1384 1 0 1 1 0 8 0 vmmpekpl 168 12934 0 12895 3 0 3 3 0 8 0 vmmpepl 168 92724 0 90796 102 14 88 96 0 357 1 vmsppl 456 1415 0 1384 7 2 5 5 0 8 0 rwobjpl 64 30471 0 25244 85 0 85 85 0 8 0 pdppl 4096 2839 0 2768 111 40 71 85 0 8 0 pvpl 32 17283 0 0 141 1 140 140 0 265 0 pmappl 248 1415 0 1384 3 0 3 3 0 8 0 extentpl 40 55 0 38 1 0 1 1 0 8 0 phpool 112 319 0 57 8 0 8 8 0 8 0 ddb{0}> machine ddbcpu 0 Invalid cpu 0 ddb{0}> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:437 witness_checkorder(fffffd806de8ccc0,9,0) at witness_checkorder+0x1047 rw_do_enter_write(fffffd806de8cca8,1) at rw_do_enter_write+0xb7 sys/kern/kern_rwlock.c:233 rrw_enter(fffffd806de8cca8,1) at rrw_enter+0xc6 sys/kern/kern_rwlock.c:616 VOP_LOCK(fffffd805ffc5870,2001) at VOP_LOCK+0xa6 sys/kern/vfs_vops.c:524 vn_lock(fffffd805ffc5870,2001) at vn_lock+0xa4 sys/kern/vfs_vnops.c:570 vfs_getcwd_common(fffffd805ffc5870,fffffd805ffc5870,0,0,200,0,55e81600abbb397b) at vfs_getcwd_common+0xd1 sys/kern/vfs_getcwd.c:287 vn_isunder(fffffd805ffc5870,fffffd805ffc5870,ffff80003c64e548) at vn_isunder+0x56 sys/kern/vfs_vnops.c:694 unp_externalize(fffffd8078909900,ec,0) at unp_externalize+0x286 sys/kern/uipc_usrreq.c:1086 soreceive(ffff80000128faf0,ffff800030156b28,ffff800030156ad8,0,ffff800030156b18,ffff800030156c9c,2d85b3409aca3509) at soreceive+0xc73 sys/kern/uipc_socket.c:1015 recvit(ffff80003c64e548,5,ffff800030156c70,0,ffff800030156d20) at recvit+0x40a sys/kern/uipc_syscalls.c:1072 sys_recvmsg(ffff80003c64e548,ffff800030156dd0,ffff800030156d20) at sys_recvmsg+0x1bf sys/kern/uipc_syscalls.c:872 syscall(ffff800030156dd0) at syscall+0xbc6 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff800030156dd0) at syscall+0xbc6 sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x191067da330, count: -14 ddb{0}> machine ddbcpu 1 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp ddb{1}> trace x86_ipi_db(ffff800029b5bff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:393 x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27 __mp_lock(ffffffff8360d908) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:113 [inline] __mp_lock(ffffffff8360d908) at __mp_lock+0x192 sys/kern/kern_lock.c:144 end trace frame: 0x0, count: -4