witness: lock order reversal: 1st 0xfffffd806bf49d58 vmmaplk (&map->lock) 2nd 0xfffffd8077b12928 inode (&ip->i_lock) lock order [1] vmmaplk (&map->lock) -> [2] inode (&ip->i_lock) #0 rw_enter+0x122 #1 rrw_enter+0xbe sys/kern/kern_rwlock.c:464 #2 VOP_LOCK+0xa6 sys/kern/vfs_vops.c:524 #3 vn_lock+0xa4 sys/kern/vfs_vnops.c:564 #4 vn_rdwr+0xd1 sys/kern/vfs_vnops.c:320 #5 vndstrategy+0x4ff sys/dev/vnd.c:342 #6 physio+0x2f6 sys/kern/kern_physio.c:162 #7 spec_read+0x155 sys/kern/spec_vnops.c:215 #8 VOP_READ+0x102 sys/kern/vfs_vops.c:227 #9 vn_read+0x17b sys/kern/vfs_vnops.c:369 #10 dofilereadv+0x230 sys/kern/sys_generic.c:252 #11 sys_readv+0xd8 sys/kern/sys_generic.c:199 #12 syscall+0xbb6 mi_syscall sys/sys/syscall_mi.h:178 [inline] #12 syscall+0xbb6 sys/arch/amd64/amd64/trap.c:577 #13 Xsyscall+0x128 lock order [2] inode (&ip->i_lock) -> [1] vmmaplk (&map->lock) #0 rw_enter_read+0xab sys/kern/kern_rwlock.c:112 #1 uvmfault_lookup+0x122 sys/uvm/uvm_fault.c:1819 #2 uvm_fault_check+0x49 sys/uvm/uvm_fault.c:672 #3 uvm_fault+0xf5 sys/uvm/uvm_fault.c:600 #4 kpageflttrap+0x2d0 sys/arch/amd64/amd64/trap.c:279 #5 kerntrap+0x14a sys/arch/amd64/amd64/trap.c:332 #6 alltraps_kern_meltdown+0x7b #7 copyout+0x57 #8 ffs_read+0x422 sys/ufs/ffs/ffs_vnops.c:254 #9 VOP_READ+0x102 sys/kern/vfs_vops.c:227 #10 vn_rdwr+0x15b #11 vmcmd_map_readvn+0x142 sys/kern/exec_subr.c:249 #12 exec_process_vmcmds+0xfb sys/kern/exec_subr.c:139 #13 sys_execve+0xbe4 sys/kern/kern_exec.c:468 #14 start_init+0x3c6 sys/kern/init_main.c:714 #15 proc_trampoline+0x10 Stopped at db_enter+0x25: addq $0x8,%rsp ddb{1}> ddb{1}> set $lines = 0 ddb{1}> set $maxwidth = 0 ddb{1}> show panic the kernel did not panic ddb{1}> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:437 witness_checkorder(fffffd8077b12928,9,0) at witness_checkorder+0x1047 rw_enter(fffffd8077b12918,1) at rw_enter+0x122 rrw_enter(fffffd8077b12918,1) at rrw_enter+0xbe sys/kern/kern_rwlock.c:464 VOP_LOCK(fffffd805f694eb0,2001) at VOP_LOCK+0xa6 sys/kern/vfs_vops.c:524 vn_lock(fffffd805f694eb0,2001) at vn_lock+0xa4 sys/kern/vfs_vnops.c:564 vn_rdwr(0,fffffd805f694eb0,ffff800011a263c0,1000,0,1,5897c6bc4fd5b81d,0,ffff800000b3e000,0) at vn_rdwr+0xd1 sys/kern/vfs_vnops.c:320 vndstrategy(fffffd806cb8ae68) at vndstrategy+0x4ff sys/dev/vnd.c:342 physio(ffffffff810efea0,2902,8000,ffffffff82505c00,ffff80002b209500) at physio+0x2f6 sys/kern/kern_physio.c:162 spec_read(ffff80002b2092f0) at spec_read+0x155 sys/kern/spec_vnops.c:215 VOP_READ(fffffd806e6a3eb8,ffff80002b209500,0,fffffd807f7d33a8) at VOP_READ+0x102 sys/kern/vfs_vops.c:227 vn_read(fffffd806bd35ee0,ffff80002b209500,0) at vn_read+0x17b sys/kern/vfs_vnops.c:369 dofilereadv(ffff8000371b6a58,3,ffff80002b209500,0,ffff80002b2095c0) at dofilereadv+0x230 sys/kern/sys_generic.c:252 sys_readv(ffff8000371b6a58,ffff80002b209670,ffff80002b2095c0) at sys_readv+0xd8 sys/kern/sys_generic.c:199 syscall(ffff80002b209670) at syscall+0xbb6 mi_syscall sys/sys/syscall_mi.h:178 [inline] syscall(ffff80002b209670) at syscall+0xbb6 sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2f4464a1010, count: -16 ddb{1}> show registers rdi 0 rsi 0x40000 acpi_pdirpa+0x2be71 rbp 0xffff80002b208db0 rbx 0xfffffd80042c63e8 rdx 0xffff8000012b6000 rcx 0xffff8000371b6a58 rax 0x3ffff acpi_pdirpa+0x2be70 r8 0xffff80002b208c90 r9 0x8080808080808080 r10 0xbba4dc68cc395f92 r11 0x5b231d140842f5b3 r12 0 r13 0xfffffd8003adee00 r14 0x3 r15 0xffffffff rip 0xffffffff81668fa5 db_enter+0x25 cs 0x8 rflags 0x246 rsp 0xffff80002b208da0 ss 0x10 db_enter+0x25: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor) tid=328224 pid=61261 tcnt=2 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=0xffff8000371b6f68,0xffff8000371b7488 process=0xffff80002b1e8000 user=0xffff80002b204000, vmspace=0xfffffd806bf49c60 estcpu=36, cpticks=0, pctcpu=0.0, user=0, sys=0, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 10931 226688 56878 0 2 0 syz-executor 61261 125293 52520 0 7 0 syz-executor *61261 328224 52520 0 7 0x4000000 syz-executor 69869 287213 58549 0 2 0 syz-executor 69869 21772 58549 0 3 0x4000080 fsleep syz-executor 69869 480266 58549 0 3 0x4000080 fsleep syz-executor 69869 364969 58549 0 3 0x4000080 fsleep syz-executor 723 205013 23926 0 2 0 syz-executor 723 201521 23926 0 3 0x4000080 fsleep syz-executor 63909 293636 1436 0 2 0 syz-executor 63909 266242 1436 0 3 0x4000080 ttyout syz-executor 70511 309213 0 0 3 0x14280 nfsidl nfsio 30536 270617 0 0 3 0x14280 nfsidl nfsio 19373 351093 0 0 3 0x14280 nfsidl nfsio 33179 207135 0 0 3 0x14280 nfsidl nfsio 96103 511121 0 0 3 0x14280 nfsidl nfsio 24705 373427 0 0 3 0x14280 nfsidl nfsio 24238 465159 0 0 3 0x14280 nfsidl nfsio 99611 57572 0 0 3 0x14280 nfsidl nfsio 33876 250663 0 0 3 0x14280 nfsidl nfsio 41872 25167 0 0 3 0x14280 nfsidl nfsio 45707 184495 0 0 3 0x14280 nfsidl nfsio 59897 92556 0 0 3 0x14280 nfsidl nfsio 74795 148790 0 0 3 0x14280 nfsidl nfsio 33624 387215 0 0 3 0x14280 nfsidl nfsio 66315 501656 0 0 3 0x14280 nfsidl nfsio 35232 69482 0 0 3 0x14280 nfsidl nfsio 15739 67216 0 0 3 0x14280 nfsidl nfsio 26252 100301 0 0 3 0x14280 nfsidl nfsio 49188 90591 0 0 3 0x14280 nfsidl nfsio 52592 224140 0 0 3 0x14280 nfsidl nfsio 76373 269497 60768 0 3 0x82 wait syz-executor 44118 463574 1 0 3 0x100083 ttyin getty 29113 342593 0 0 3 0x14200 acct acct 29925 162043 50830 0 3 0x100082 sbwait ndp 50830 321957 49169 0 3 0x10008a sigsusp sh 85910 112108 0 0 3 0x14200 bored sosplice 52520 97143 60768 0 3 0x82 nanoslp syz-executor 1436 416129 60768 0 3 0x82 nanoslp syz-executor 56878 370039 60768 0 3 0x82 nanoslp syz-executor 49169 213638 60768 0 3 0x82 wait syz-executor 23926 457872 60768 0 3 0x82 nanoslp syz-executor 58549 448634 60768 0 3 0x82 nanoslp syz-executor 82795 186002 60768 0 3 0x82 nanoslp syz-executor 60768 324984 80191 0 3 0x82 kqread syz-executor 80191 378910 83664 0 3 0x10008a sigsusp ksh 83664 368380 52775 0 3 0x98 kqread sshd-session 52775 280190 22927 0 3 0x92 kqread sshd-session 22927 294332 1 0 3 0x88 kqread sshd 98865 231322 29419 74 3 0x1100092 bpf pflogd 29419 171422 1 0 3 0x80 sbwait pflogd 84691 812 71620 73 3 0x1100090 kqread syslogd 71620 42027 1 0 3 0x100082 sbwait syslogd 90966 333399 1 0 3 0x100080 kqread resolvd 13973 446905 19138 77 3 0x100092 kqread dhcpleased 50832 312913 19138 77 3 0x100092 kqread dhcpleased 19138 114126 1 0 3 0x80 kqread dhcpleased 67696 80482 0 0 3 0x14200 bored smr 22404 44510 0 0 2 0x14200 zerothread 31335 412892 0 0 3 0x14200 aiodoned aiodoned 83407 522593 0 0 3 0x14200 syncer update 30676 396918 0 0 3 0x14200 cleaner cleaner 19868 345764 0 0 3 0x14200 reaper reaper 59047 280122 0 0 3 0x14200 pgdaemon pagedaemon 81468 152303 0 0 3 0x14200 bored viomb 441 459613 0 0 3 0x40014200 acpi0 acpi0 97953 160888 0 0 3 0x40014200 idle1 84877 427278 0 0 3 0x14200 bored softnet3 91417 54801 0 0 3 0x14200 bored softnet2 41560 315795 0 0 3 0x14200 bored softnet1 48079 121473 0 0 3 0x14200 bored softnet0 33040 369455 0 0 3 0x14200 bored systqmp 24278 128267 0 0 3 0x14200 bored systq 18216 111312 0 0 3 0x14200 tmoslp softclockmp 69729 85175 0 0 3 0x40014200 tmoslp softclock 5039 309465 0 0 3 0x40014200 idle0 1 371611 0 0 3 0x80082 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks Process 61261 (syz-executor) thread 0xffff8000371b6a58 (328224) shared rwlock vmmaplk r = 0 (0xfffffd806bf49d58) #0 witness_lock+0x5bb stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5bb sys/kern/subr_witness.c:1155 #1 uvm_vslock_device+0x149 sys/uvm/uvm_glue.c:172 #2 physio+0x277 sys/kern/kern_physio.c:139 #3 spec_read+0x155 sys/kern/spec_vnops.c:215 #4 VOP_READ+0x102 sys/kern/vfs_vops.c:227 #5 vn_read+0x17b sys/kern/vfs_vnops.c:369 #6 dofilereadv+0x230 sys/kern/sys_generic.c:252 #7 sys_readv+0xd8 sys/kern/sys_generic.c:199 #8 syscall+0xbb6 mi_syscall sys/sys/syscall_mi.h:178 [inline] #8 syscall+0xbb6 sys/arch/amd64/amd64/trap.c:577 #9 Xsyscall+0x128 exclusive kernel_lock &kernel_lock r = 0 (0xffffffff835f75c8) #0 witness_lock+0x5bb stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5bb sys/kern/subr_witness.c:1155 #1 vn_read+0x56 sys/kern/vfs_vnops.c:351 #2 dofilereadv+0x230 sys/kern/sys_generic.c:252 #3 sys_readv+0xd8 sys/kern/sys_generic.c:199 #4 syscall+0xbb6 mi_syscall sys/sys/syscall_mi.h:178 [inline] #4 syscall+0xbb6 sys/arch/amd64/amd64/trap.c:577 #5 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10209 11252K 11386K 166960K 12108 0 pcb 17 16K 17K 166960K 298 0 rtable 223 8K 8K 166960K 450 0 pf 34 17K 19K 166960K 64 0 ifaddr 42 7K 7K 166960K 54 0 ifgroup 55 2K 2K 166960K 68 0 sysctl 2 0K 0K 166960K 2 0 counters 64 36K 36K 166960K 70 0 ioctlops 0 0K 4K 166960K 1609 0 iov 0 0K 16K 166960K 40 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1459 92K 92K 166960K 1907 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 5K 166960K 13 0 VM map 2 1K 1K 166960K 2 0 sem 12 0K 0K 166960K 25 0 dirhash 12 2K 2K 166960K 27 0 ACPI 1690 195K 286K 166960K 12468 0 file desc 19 69K 93K 166960K 664 0 sigio 0 0K 0K 166960K 9 0 proc 72 91K 115K 166960K 599 0 subproc 104 6K 6K 166960K 117 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 0 0K 0K 166960K 149 0 in_multi 92 7K 7K 166960K 133 0 ether_multi 1 0K 0K 166960K 4 0 mrt 1 0K 0K 166960K 3 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 422 0 fusefs mount 1 32K 32K 166960K 1 0 pfkey data 0 0K 0K 166960K 2 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 253 73K 74K 166960K 7737 0 UVM aobj 22 2K 2K 166960K 24 0 pinsyscall 45 90K 109K 166960K 1768 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 0 0K 0K 166960K 33 0 NDP 12 0K 1K 166960K 35 0 temp 79 6828K 6956K 166960K 29116 0 kqueue 14 22K 32K 166960K 103 0 SYN cache 2 16K 16K 166960K 2 0 ddb{1}> 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 120 144 0 140 3 2 1 3 0 8 0 rtentry 112 137 0 37 4 0 4 4 0 8 0 unpcb 144 476 0 458 4 3 1 4 0 8 0 syncache 336 4 0 4 2 1 1 1 0 8 1 tcpcb 808 276 0 271 8 4 4 8 0 8 3 arp 120 23 0 4 1 0 1 1 0 8 0 ipq 40 1 0 1 1 1 0 1 0 8 0 ipqe 40 3 0 3 1 1 0 1 0 8 0 inpcb 336 970 0 958 13 6 7 13 0 8 5 nd6 136 31 0 7 1 0 1 1 0 8 0 pkpcb 40 7 0 7 1 0 1 1 0 8 1 kcovpl 48 9 0 1 1 0 1 1 0 8 0 pffrag 232 6 0 2 1 0 1 1 0 482 0 pffrnode 88 6 0 2 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 pfstitem 24 62 0 10 1 0 1 1 0 8 0 pfstkey 128 62 0 10 2 0 2 2 0 8 0 pfstate 376 62 0 10 6 0 6 6 0 8 0 pfrule 1344 31 0 25 2 0 2 2 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 546 0 133 29 3 26 29 0 8 0 art_table 32 547 0 133 4 0 4 4 0 8 0 art_node 16 136 0 48 1 0 1 1 0 8 0 sysvmsgpl 40 3 0 0 1 0 1 1 0 8 0 semapl 112 22 0 12 1 0 1 1 0 8 0 shmpl 112 21 0 2 1 0 1 1 0 8 0 dirhash 1024 27 0 10 3 0 3 3 0 8 0 dino2pl 256 2513 0 1011 95 0 95 95 0 8 0 ffsino 272 2513 0 1011 102 0 102 102 0 8 0 nchpl 144 3411 0 1727 63 0 63 63 0 8 0 uvmvnodes 80 2953 0 0 61 0 61 61 0 8 0 vnodes 216 2953 0 0 165 0 165 165 0 8 0 namei 1024 11106 0 11106 2 1 1 2 0 8 1 percpumem 16 49 0 3 1 0 1 1 0 8 0 kstatmem 264 30 0 6 2 0 2 2 0 8 0 scsiplug 72 2 0 2 1 1 0 1 0 8 0 scxspl 216 10340 0 10340 10 8 2 8 1 8 2 plimitpl 152 106 0 89 1 0 1 1 0 8 0 sigapl 424 984 0 911 10 1 9 9 0 8 0 futexpl 64 8136 0 8132 1 0 1 1 0 8 0 knotepl 120 577 0 0 18 0 18 18 0 8 0 kqueuepl 216 194 0 183 3 2 1 3 0 8 0 pipepl 320 153 0 124 3 0 3 3 0 8 0 fdescpl 496 944 0 911 5 0 5 5 0 8 0 filepl 152 5517 0 5257 16 2 14 16 0 8 3 lockfpl 104 187 0 184 1 0 1 1 0 8 0 lockfspl 48 79 0 76 1 0 1 1 0 8 0 sessionpl 144 25 0 16 1 0 1 1 0 8 0 pgrppl 48 39 0 22 1 0 1 1 0 8 0 ucredpl 104 893 0 879 1 0 1 1 0 8 0 zombiepl 144 913 0 911 1 0 1 1 0 8 0 processpl 1160 984 0 911 6 0 6 6 0 8 0 procpl 648 1873 0 1794 8 0 8 8 0 8 0 srpgc 96 4 0 4 1 1 0 1 0 8 0 sosppl 168 5 0 5 1 0 1 1 0 8 1 sockpl 664 1633 0 1599 15 6 9 15 0 8 6 mcl64k 65536 4 0 0 1 0 1 1 0 8 0 mcl16k 16384 2 0 0 1 0 1 1 0 8 0 mcl12k 12288 1 0 0 1 0 1 1 0 8 0 mcl9k 9216 2 0 0 1 0 1 1 0 8 0 mcl8k 8192 6 0 0 1 0 1 1 0 8 0 mcl4k 4096 168 0 0 21 0 21 21 0 8 0 mcl2k 2048 30 0 0 4 0 4 4 0 8 0 mtagpl 96 14 0 0 1 0 1 1 0 8 0 mbufpl 256 239 0 0 14 0 14 14 0 8 0 bufpl 280 3225 0 103 223 0 223 223 0 8 0 anonpl 24 198512 0 195003 47 1 46 47 0 185 12 amapchunkpl 152 24784 0 24241 26 1 25 26 0 158 3 amappl16 200 5311 0 5287 19 5 14 14 0 8 7 amappl15 192 5 0 5 1 1 0 1 0 8 0 amappl14 184 123 0 110 1 0 1 1 0 8 0 amappl13 176 10 0 10 1 1 0 1 0 8 0 amappl12 168 1603 0 1569 4 1 3 3 0 8 0 amappl11 160 59 0 45 1 0 1 1 0 8 0 amappl10 152 10 0 10 2 2 0 1 0 8 0 amappl9 144 155 0 155 1 1 0 1 0 8 0 amappl8 136 23 0 21 1 0 1 1 0 8 0 amappl7 128 126 0 113 1 0 1 1 0 8 0 amappl6 120 170 0 168 1 0 1 1 0 8 0 amappl5 112 164 0 152 1 0 1 1 0 8 0 amappl4 104 310 0 292 1 0 1 1 0 8 0 amappl3 96 4719 0 4614 3 0 3 3 0 8 0 amappl2 88 1228 0 1141 3 0 3 3 0 8 0 amappl1 80 9438 0 8841 16 2 14 15 0 8 0 amappl 88 7296 0 7108 5 0 5 5 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 128 255 0 255 2 2 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 19 0 18 1 0 1 1 0 8 0 aobjpl 72 23 0 2 1 0 1 1 0 8 0 uaddrrnd 24 944 0 911 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 944 0 911 1 0 1 1 0 8 0 vmmpekpl 168 8809 0 8763 3 0 3 3 0 8 0 vmmpepl 168 65670 0 63722 96 1 95 96 0 357 6 vmsppl 448 943 0 911 6 2 4 5 0 8 0 rwobjpl 56 24607 0 20643 57 0 57 57 0 8 1 pdppl 4096 1895 0 1822 107 32 75 85 0 8 2 pvpl 32 14703 0 0 120 1 119 119 0 265 0 pmappl 248 943 0 911 3 0 3 3 0 8 0 extentpl 40 55 0 38 1 0 1 1 0 8 0 phpool 112 413 0 51 11 0 11 11 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp ddb{0}> trace x86_ipi_db(ffffffff83424ff0) 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(ffffffff835f73c0) at __mp_lock+0x199 __mp_lock_spin sys/kern/kern_lock.c:113 [inline] __mp_lock(ffffffff835f73c0) at __mp_lock+0x199 sys/kern/kern_lock.c:144 intr_handler(ffff80003479e0f0,ffff800000069c00) at intr_handler+0xe1 sys/arch/amd64/amd64/intr.c:553 Xintr_ioapic_edge16_untramp() at Xintr_ioapic_edge16_untramp+0x18f __mp_lock(ffffffff835f73c0) at __mp_lock+0x19e __mp_lock_spin sys/kern/kern_lock.c:113 [inline] __mp_lock(ffffffff835f73c0) at __mp_lock+0x19e sys/kern/kern_lock.c:144 intr_handler(ffff80003479e250,ffff800000079e00) at intr_handler+0xe1 sys/arch/amd64/amd64/intr.c:553 Xintr_ioapic_edge25_untramp() at Xintr_ioapic_edge25_untramp+0x18f __mp_lock(ffffffff835f73c0) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:113 [inline] __mp_lock(ffffffff835f73c0) at __mp_lock+0x192 sys/kern/kern_lock.c:144 softintr_dispatch(0) at softintr_dispatch+0x5b sys/arch/amd64/amd64/softintr.c:88 Xsoftclock() at Xsoftclock+0x27 end of kernel end trace frame: 0x757458846640, count: -12 ddb{0}> machine ddbcpu 1 Stopped at db_enter+0x25: addq $0x8,%rsp ddb{1}> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:437 witness_checkorder(fffffd8077b12928,9,0) at witness_checkorder+0x1047 rw_enter(fffffd8077b12918,1) at rw_enter+0x122 rrw_enter(fffffd8077b12918,1) at rrw_enter+0xbe sys/kern/kern_rwlock.c:464 VOP_LOCK(fffffd805f694eb0,2001) at VOP_LOCK+0xa6 sys/kern/vfs_vops.c:524 vn_lock(fffffd805f694eb0,2001) at vn_lock+0xa4 sys/kern/vfs_vnops.c:564 vn_rdwr(0,fffffd805f694eb0,ffff800011a263c0,1000,0,1,5897c6bc4fd5b81d,0,ffff800000b3e000,0) at vn_rdwr+0xd1 sys/kern/vfs_vnops.c:320 vndstrategy(fffffd806cb8ae68) at vndstrategy+0x4ff sys/dev/vnd.c:342 physio(ffffffff810efea0,2902,8000,ffffffff82505c00,ffff80002b209500) at physio+0x2f6 sys/kern/kern_physio.c:162 spec_read(ffff80002b2092f0) at spec_read+0x155 sys/kern/spec_vnops.c:215 VOP_READ(fffffd806e6a3eb8,ffff80002b209500,0,fffffd807f7d33a8) at VOP_READ+0x102 sys/kern/vfs_vops.c:227 vn_read(fffffd806bd35ee0,ffff80002b209500,0) at vn_read+0x17b sys/kern/vfs_vnops.c:369 dofilereadv(ffff8000371b6a58,3,ffff80002b209500,0,ffff80002b2095c0) at dofilereadv+0x230 sys/kern/sys_generic.c:252 sys_readv(ffff8000371b6a58,ffff80002b209670,ffff80002b2095c0) at sys_readv+0xd8 sys/kern/sys_generic.c:199 syscall(ffff80002b209670) at syscall+0xbb6 mi_syscall sys/sys/syscall_mi.h:178 [inline] syscall(ffff80002b209670) at syscall+0xbb6 sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2f4464a1010, count: -16