witness: lock order reversal: 1st 0xffff8000fffed0f0 fdlock (&newfdp->fd_fd.fd_lock) 2nd 0xfffffd806e0c16b8 inode (&ip->i_lock) lock order [1] fdlock (&newfdp->fd_fd.fd_lock) -> [2] inode (&ip->i_lock) lock order data 0xffffffff8337242b -> 0xffffffff833676f0 is missing lock order [2] inode (&ip->i_lock) -> [3] sbufrcv (&so->so_rcv.sb_lock) #0 rw_do_enter_write+0xba sys/kern/kern_rwlock.c:234 #1 sblock+0xb6 sys/kern/uipc_socket2.c:536 #2 soreceive+0x27d sys/kern/uipc_socket.c:878 #3 fifo_read+0x117 sys/miscfs/fifofs/fifo_vnops.c:264 #4 VOP_READ+0x101 sys/kern/vfs_vops.c:227 #5 vn_rdwr+0x15b sys/kern/vfs_vnops.c:-1 #6 vndsetcred+0xa1 sys/dev/vnd.c:685 #7 vndioctl+0xdfb sys/dev/vnd.c:486 #8 VOP_IOCTL+0xac sys/kern/vfs_vops.c:264 #9 vn_ioctl+0xf8 sys/kern/vfs_vnops.c:531 #10 sys_ioctl+0x674 sys/kern/sys_generic.c:-1 #11 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #11 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:765 #12 Xsyscall+0x128 lock order [3] sbufrcv (&so->so_rcv.sb_lock) -> [1] fdlock (&newfdp->fd_fd.fd_lock) #0 rw_do_enter_write+0xba sys/kern/kern_rwlock.c:234 #1 unp_externalize+0x3cf sys/kern/uipc_usrreq.c:1074 #2 soreceive+0xc24 sys/kern/uipc_socket.c:1017 #3 recvit+0x40b sys/kern/uipc_syscalls.c:1078 #4 sys_recvmsg+0x1bf sys/kern/uipc_syscalls.c:878 #5 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #5 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:765 #6 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:438 witness_checkorder(fffffd806e0c16b8,9,0) at witness_checkorder+0x10b9 sys/kern/subr_witness.c:-1 rw_do_enter_write(fffffd806e0c16a0,1) at rw_do_enter_write+0xba sys/kern/kern_rwlock.c:234 rrw_enter(fffffd806e0c16a0,1) at rrw_enter+0xc6 sys/kern/kern_rwlock.c:621 VOP_LOCK(fffffd806e0cc120,2001) at VOP_LOCK+0xa3 sys/kern/vfs_vops.c:527 vn_lock(fffffd806e0cc120,2001) at vn_lock+0xa4 sys/kern/vfs_vnops.c:570 vn_closefile(fffffd806c83a7a0,ffff8000fffe62b8) at vn_closefile+0x111 vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd806c83a7a0,ffff8000fffe62b8) at vn_closefile+0x111 sys/kern/vfs_vnops.c:615 fdrop(fffffd806c83a7a0,ffff8000fffe62b8) at fdrop+0x121 sys/kern/kern_descrip.c:1280 knote_drop(fffffd8061a4bad0,ffff8000fffe62b8) at knote_drop+0x1a1 sys/kern/kern_event.c:2296 knote_remove(ffff8000fffe62b8,fffffd806f196460,fffffd806f1964f0,6,0) at knote_remove+0x2f6 sys/kern/kern_event.c:2180 knote_fdclose(ffff8000fffe62b8,6) at knote_fdclose+0xf9 sys/kern/kern_event.c:2203 fdrelease(ffff8000fffe62b8,6) at fdrelease+0xf9 sys/kern/kern_descrip.c:760 syscall(ffff80003c41a1f0) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003c41a1f0) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:765 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x83642467a50, count: -14 ddb{0}> show registers rdi 0 rsi 0 rbp 0xffff80003c419cc0 rbx 0 rdx 0 rcx 0xffff8000fffe62b8 rax 0xffffffff83877ff0 cpu_info_full_primary+0x1ff0 r8 0xffff80003c419ba0 r9 0x8080808080808080 r10 0x7c8515b3942dff11 r11 0xb0b3441b10c2d061 r12 0xfffffd8003f27d00 r13 0xfffffd8004714928 r14 0x3 r15 0xffffffff834049f1 substchar+0xa39c rip 0xffffffff81027c95 db_enter+0x25 cs 0x8 rflags 0x246 rsp 0xffff80003c419cb0 ss 0x10 db_enter+0x25: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor) tid=306439 pid=97422 tcnt=3 stat=onproc flags process=0 proc=4000000 runpri=32, usrpri=50, slppri=32, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff8000fffe7a10,0xffff800039ff9cc0 process=0xffff8000fffeb038 user=0xffff80003c415000, vmspace=0xfffffd800c3c39a8 estcpu=36, cpticks=0, pctcpu=0.0, user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 97422 341034 17719 0 2 0 syz-executor *97422 306439 17719 0 7 0x4000000 syz-executor 97422 398137 17719 0 7 0x4000000 syz-executor 60530 76293 93319 0 2 0 syz-executor 60530 107 93319 0 3 0x4000080 fsleep syz-executor 64349 375501 37084 0 2 0 syz-executor 64349 259234 37084 0 3 0x4000000 biowait syz-executor 64349 446339 37084 0 3 0x4000000 inode syz-executor 35032 514802 61425 0 2 0 syz-executor 35032 105948 61425 0 3 0x4000080 fifow syz-executor 35032 354444 61425 0 2 0x4000000 syz-executor 35032 444831 61425 0 3 0x4000080 fsleep syz-executor 21395 362759 99304 0 3 0x80 fsleep syz-executor 21395 478573 99304 0 3 0x4000080 sbwait syz-executor 21395 197478 99304 0 3 0x4000080 sbwait syz-executor 84612 272555 6352 0 3 0x90 fsleep syz-executor 84612 380759 6352 0 3 0x4000090 ttyout syz-executor 86535 373624 77768 0 3 0x80 fsleep syz-executor 86535 300234 77768 0 3 0x4000080 bell syz-executor 37084 169462 17555 0 3 0x82 nanoslp syz-executor 2197 347077 0 0 3 0x14200 acct acct 77768 369832 17555 0 3 0x82 nanoslp syz-executor 6352 282878 17555 0 3 0x82 nanoslp syz-executor 77619 300162 17555 0 3 0x82 nanoslp syz-executor 99304 221046 17555 0 3 0x82 nanoslp syz-executor 61425 499845 17555 0 3 0x82 nanoslp syz-executor 17719 70880 17555 0 3 0x82 nanoslp syz-executor 93319 377958 17555 0 3 0x82 nanoslp syz-executor 17555 349968 79037 0 3 0x82 kqread syz-executor 79037 192181 47340 0 3 0x10008a sigsusp ksh 47340 8462 86236 0 3 0x98 kqread sshd-session 86236 250612 17508 0 3 0x92 kqread sshd-session 87193 523594 1 0 3 0x100083 ttyopn getty 17508 475479 1 0 3 0x88 kqread sshd 73940 511896 28954 74 3 0x1100092 bpf pflogd 28954 68621 1 0 3 0x80 sbwait pflogd 21839 242480 33064 73 3 0x1100090 kqread syslogd 33064 70075 1 0 3 0x100082 sbwait syslogd 2051 386529 1 0 3 0x100080 kqread resolvd 84769 469123 12580 77 3 0x100092 kqread dhcpleased 15678 260246 12580 77 3 0x100092 kqread dhcpleased 12580 36989 1 0 3 0x80 kqread dhcpleased 883 183072 0 0 3 0x14200 bored smr 10899 127339 0 0 3 0x14200 pgzero zerothread 62503 235727 0 0 3 0x14200 aiodoned aiodoned 18232 108503 0 0 3 0x14200 syncer update 53518 19593 0 0 3 0x14200 cleaner cleaner 24396 3505 0 0 3 0x14200 reaper reaper 99140 440951 0 0 3 0x14200 pgdaemon pagedaemon 36710 323244 0 0 3 0x14200 bored viomb 43919 494668 0 0 3 0x40014200 acpi0 acpi0 91858 182077 0 0 3 0x40014200 idle1 42885 4306 0 0 3 0x14200 bored softnet1 6676 246580 0 0 3 0x14200 bored softnet0 46858 87334 0 0 3 0x14200 bored systqmp 47397 38718 0 0 3 0x14200 bored systq 36953 367796 0 0 3 0x14200 tmoslp softclockmp 33133 125403 0 0 3 0x40014200 tmoslp softclock 5237 464728 0 0 3 0x40014200 idle0 1 51783 0 0 3 0x82 wait init 0 0 -1 0 3 0x10010200 scheduler swapper ddb{0}> show all locks Process 97422 (syz-executor) thread 0xffff8000fffe62b8 (306439) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff8389d228) #0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160 #1 vn_closefile+0x41 sys/kern/vfs_vnops.c:608 #2 fdrop+0x121 sys/kern/kern_descrip.c:1280 #3 knote_drop+0x1a1 sys/kern/kern_event.c:2296 #4 knote_remove+0x2f6 sys/kern/kern_event.c:2180 #5 knote_fdclose+0xf9 sys/kern/kern_event.c:2203 #6 fdrelease+0xf9 sys/kern/kern_descrip.c:760 #7 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #7 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:765 #8 Xsyscall+0x128 exclusive rwlock fdlock r = 0 (0xffff8000fffed0f0) #0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160 #1 rw_do_enter_write+0x419 sys/kern/kern_rwlock.c:320 #2 sys_close+0xd0 sys/kern/kern_descrip.c:778 #3 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #3 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:765 #4 Xsyscall+0x128 Process 64349 (syz-executor) thread 0xffff800039ff9a18 (259234) exclusive rrwlock inode r = 0 (0xfffffd807ab55a20) #0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160 #1 rw_do_enter_write+0x419 sys/kern/kern_rwlock.c:320 #2 rrw_enter+0xc6 sys/kern/kern_rwlock.c:621 #3 VOP_LOCK+0xa3 sys/kern/vfs_vops.c:527 #4 vn_lock+0xa4 sys/kern/vfs_vnops.c:570 #5 vn_write+0x18f sys/kern/vfs_vnops.c:405 #6 dofilewritev+0x242 sys/kern/sys_generic.c:380 #7 sys_write+0xa2 sys/kern/sys_generic.c:300 #8 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #8 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:765 #9 Xsyscall+0x128 ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10205 11054K 11229K 166960K 11895 0 pcb 18 16K 18K 166960K 118 0 rtable 238 9K 10K 166960K 555 0 pf 35 17K 21K 166960K 124 0 ifaddr 40 7K 8K 166960K 87 0 ifgroup 55 2K 2K 166960K 139 0 sysctl 4 1K 9K 166960K 79 0 counters 68 36K 38K 166960K 174 0 ioctlops 0 0K 4K 166960K 1698 0 iov 0 0K 20K 166960K 40 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1374 86K 87K 166960K 1799 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 2K 9K 166960K 11 0 VM map 2 1K 1K 166960K 2 0 sem 12 1K 1K 166960K 82 0 dirhash 12 2K 2K 166960K 36 0 ACPI 1692 195K 286K 166960K 12470 0 file desc 18 65K 236K 166960K 817 0 sigio 0 0K 0K 166960K 8 0 proc 73 115K 180K 166960K 637 0 subproc 72 4K 4K 166960K 81 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 0 0K 0K 166960K 67 0 in_multi 88 6K 7K 166960K 147 0 ether_multi 1 0K 0K 166960K 4 0 mrt 2 0K 0K 166960K 5 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 91 413K 413K 166960K 91 0 exec 0 0K 1K 166960K 468 0 fusefs mount 1 32K 32K 166960K 1 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 261 159K 173K 166960K 8998 0 UVM aobj 19 5K 5K 166960K 21 0 pinsyscall 43 86K 104K 166960K 1949 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 0 0K 0K 166960K 57 0 NDP 12 0K 2K 166960K 57 0 temp 72 8658K 8724K 166960K 30403 0 kqueue 15 24K 28K 166960K 152 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 26 0 0 1 0 1 1 0 8 0 rtpcb 120 114 0 111 2 0 2 2 0 8 1 rtentry 176 139 0 37 6 0 6 6 0 8 0 unpcb 144 512 0 493 9 7 2 6 0 8 1 syncache 336 4 0 4 2 2 0 1 0 8 0 tcpcb 736 307 0 303 11 10 1 11 0 8 0 arp 136 23 0 6 1 0 1 1 0 8 0 inpcb 328 960 0 947 10 8 2 10 0 8 0 nd6 152 29 0 7 2 0 2 2 0 8 0 pkpcb 40 4 0 4 4 3 1 1 0 8 1 kcovpl 48 9 0 1 1 0 1 1 0 8 0 mppekey 1024 3 0 3 2 2 0 1 0 8 0 ppxss 1192 42 0 42 1 0 1 1 0 8 1 pppxif 1504 8 0 8 2 1 1 1 0 8 1 pfstscr 40 1 0 1 1 1 0 1 0 8 0 pffrag 232 9 0 0 1 0 1 1 0 482 0 pffrnode 88 7 0 0 1 0 1 1 0 8 0 pffrent 40 12 0 3 1 0 1 1 0 8 0 pfosfp 40 1430 0 1006 5 0 5 5 0 8 0 pfosfpen 112 1430 0 715 21 0 21 21 0 8 0 pfanchor 1288 1 0 0 1 0 1 1 0 8 0 pfstitem 24 61 0 23 1 0 1 1 0 8 0 pfstkey 128 62 0 24 2 0 2 2 0 8 0 pfstate 384 62 0 24 5 1 4 5 0 8 0 pfrule 1344 25 0 19 2 1 1 2 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 548 0 135 31 2 29 29 0 8 2 art_table 40 550 0 135 5 0 5 5 0 8 0 art_node 32 138 0 46 1 0 1 1 0 8 0 sysvmsgpl 40 41 0 1 1 0 1 1 0 8 0 semapl 112 80 0 70 1 0 1 1 0 8 0 shmpl 112 18 0 2 1 0 1 1 0 8 0 dirhash 1024 33 0 16 3 0 3 3 0 8 0 dino2pl 256 2835 0 1319 96 0 96 96 0 8 0 ffsino 296 2835 0 1319 117 0 117 117 0 8 0 nchpl 144 3924 0 2215 64 0 64 64 0 8 0 rtmask 32 9 0 9 3 2 1 1 0 8 1 vnodes 216 3087 0 0 172 0 172 172 0 8 0 namei 1024 12946 0 12946 2 1 1 2 0 8 1 percpumem 16 102 0 53 1 0 1 1 0 8 0 kstatmem 264 80 0 54 4 1 3 3 0 8 0 scxspl 216 30252 0 30251 10 9 1 8 1 8 0 plimitpl 152 122 0 104 1 0 1 1 0 8 0 sigapl 424 1105 0 1056 7 1 6 7 0 8 0 knotepl 120 551 0 0 17 0 17 17 0 8 0 kqueuepl 224 266 0 253 3 2 1 2 0 8 0 pipepl 344 174 0 145 3 0 3 3 0 8 0 fdescpl 528 1083 0 1051 3 0 3 3 0 8 0 filepl 160 6338 0 6099 24 12 12 20 0 8 2 lockfpl 104 442 0 440 3 2 1 2 0 8 0 lockfspl 48 140 0 138 1 0 1 1 0 8 0 sessionpl 144 24 0 15 1 0 1 1 0 8 0 pgrppl 48 40 0 23 1 0 1 1 0 8 0 ucredpl 104 875 0 861 1 0 1 1 0 8 0 zombiepl 144 1057 0 1056 1 0 1 1 0 8 0 processpl 1232 1105 0 1056 5 1 4 5 0 8 0 procpl 664 2197 0 2136 6 0 6 6 0 8 0 sosppl 176 2 0 2 1 1 0 1 0 8 0 sockpl 752 1608 0 1573 32 24 8 28 0 8 4 mcl64k 65536 19 0 0 3 0 3 3 0 8 0 mcl16k 16384 2 0 0 1 0 1 1 0 8 0 mcl8k 8192 2 0 0 1 0 1 1 0 8 0 mcl4k 4096 130 0 0 17 0 17 17 0 8 0 mcl2k 2048 80 0 0 8 1 7 7 0 8 0 mtagpl 96 1 0 0 1 0 1 1 0 8 0 mbufpl 256 3132 0 0 194 0 194 194 0 8 0 bufpl 280 12647 0 6510 439 0 439 439 0 8 0 anonpl 32 10430 0 0 84 0 84 84 0 246 0 amapchunkpl 152 29204 0 28648 36 12 24 30 0 158 2 amappl16 200 5418 0 5371 30 16 14 25 0 8 5 amappl15 192 4 0 4 1 1 0 1 0 8 0 amappl14 184 10 0 10 3 3 0 1 0 8 0 amappl13 176 444 0 443 1 0 1 1 0 8 0 amappl12 168 1451 0 1407 3 0 3 3 0 8 0 amappl11 160 6 0 6 1 1 0 1 0 8 0 amappl10 152 83 0 69 1 0 1 1 0 8 0 amappl9 144 245 0 245 1 1 0 1 0 8 0 amappl8 136 30 0 28 1 0 1 1 0 8 0 amappl7 128 83 0 81 1 0 1 1 0 8 0 amappl6 120 291 0 277 1 0 1 1 0 8 0 amappl5 112 77 0 66 1 0 1 1 0 8 0 amappl4 104 431 0 401 1 0 1 1 0 8 0 amappl3 96 5050 0 4942 4 1 3 3 0 8 0 amappl2 88 1192 0 1114 2 0 2 2 0 8 0 amappl1 80 12016 0 11420 16 2 14 15 0 8 0 amappl 88 8155 0 7970 5 0 5 5 0 92 0 uvmvnodes 80 3087 0 0 63 0 63 63 0 8 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma2048 2048 1 0 1 1 1 0 1 0 8 0 dma1024 1024 1 0 0 1 0 1 1 0 8 0 dma512 512 1 0 1 1 1 0 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 7 0 7 2 2 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 20 0 2 1 0 1 1 0 8 0 uaddrrnd 24 1083 0 1051 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 1083 0 1051 1 0 1 1 0 8 0 vmmpekpl 168 10071 0 10029 4 1 3 3 0 8 0 vmmpepl 168 76376 0 74376 108 12 96 104 0 357 9 vmsppl 488 1082 0 1051 7 3 4 5 0 8 0 rwobjpl 80 27030 0 22953 85 1 84 84 0 8 0 pdppl 4096 2174 0 2102 104 32 72 84 0 8 0 pvpl 32 17334 0 0 140 0 140 140 0 265 0 pmappl 256 1082 0 1051 3 0 3 3 0 8 0 extentpl 40 45 0 27 1 0 1 1 0 8 0 phpool 112 485 0 54 13 0 13 13 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:438 witness_checkorder(fffffd806e0c16b8,9,0) at witness_checkorder+0x10b9 sys/kern/subr_witness.c:-1 rw_do_enter_write(fffffd806e0c16a0,1) at rw_do_enter_write+0xba sys/kern/kern_rwlock.c:234 rrw_enter(fffffd806e0c16a0,1) at rrw_enter+0xc6 sys/kern/kern_rwlock.c:621 VOP_LOCK(fffffd806e0cc120,2001) at VOP_LOCK+0xa3 sys/kern/vfs_vops.c:527 vn_lock(fffffd806e0cc120,2001) at vn_lock+0xa4 sys/kern/vfs_vnops.c:570 vn_closefile(fffffd806c83a7a0,ffff8000fffe62b8) at vn_closefile+0x111 vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd806c83a7a0,ffff8000fffe62b8) at vn_closefile+0x111 sys/kern/vfs_vnops.c:615 fdrop(fffffd806c83a7a0,ffff8000fffe62b8) at fdrop+0x121 sys/kern/kern_descrip.c:1280 knote_drop(fffffd8061a4bad0,ffff8000fffe62b8) at knote_drop+0x1a1 sys/kern/kern_event.c:2296 knote_remove(ffff8000fffe62b8,fffffd806f196460,fffffd806f1964f0,6,0) at knote_remove+0x2f6 sys/kern/kern_event.c:2180 knote_fdclose(ffff8000fffe62b8,6) at knote_fdclose+0xf9 sys/kern/kern_event.c:2203 fdrelease(ffff8000fffe62b8,6) at fdrelease+0xf9 sys/kern/kern_descrip.c:760 syscall(ffff80003c41a1f0) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003c41a1f0) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:765 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x83642467a50, count: -14 ddb{0}> machine ddbcpu 1 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp ddb{1}> trace x86_ipi_db(ffff8000299edff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394 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(ffffffff8389d020) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff8389d020) at __mp_lock+0x192 sys/kern/kern_lock.c:165 syscall(ffff80003c4736c0) at syscall+0xaf4 mi_syscall sys/sys/syscall_mi.h:175 [inline] syscall(ffff80003c4736c0) at syscall+0xaf4 sys/arch/amd64/amd64/trap.c:765 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x8362aab8d00, count: -6