witness: lock order reversal: 1st 0xffff800010fca518 sbufsnd (&so->so_snd.sb_lock) 2nd 0xfffffd806e0bcf00 inode (&ip->i_lock) lock order [1] sbufsnd (&so->so_snd.sb_lock) -> [2] inode (&ip->i_lock) lock order data 0xffffffff833d1e1a -> 0xffffffff83343bfc 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:870 #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:684 #7 vndioctl+0xdfe 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+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:746 #12 Xsyscall+0x128 lock order [3] sbufrcv (&so->so_rcv.sb_lock) -> [1] sbufsnd (&so->so_snd.sb_lock) #0 rw_do_enter_write+0xba sys/kern/kern_rwlock.c:234 #1 sblock+0xb6 sys/kern/uipc_socket2.c:536 #2 sosplice+0x3e1 sys/kern/uipc_socket.c:1347 #3 sys_setsockopt+0x2ba sys/kern/uipc_syscalls.c:1227 #4 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #4 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:746 #5 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(fffffd806e0bcf00,9,0) at witness_checkorder+0x10b9 sys/kern/subr_witness.c:-1 rw_do_enter_write(fffffd806e0bcee8,1) at rw_do_enter_write+0xba sys/kern/kern_rwlock.c:234 rrw_enter(fffffd806e0bcee8,1) at rrw_enter+0xc6 sys/kern/kern_rwlock.c:621 VOP_LOCK(fffffd807268acb8,2001) at VOP_LOCK+0xa3 sys/kern/vfs_vops.c:527 vn_lock(fffffd807268acb8,2001) at vn_lock+0xa4 sys/kern/vfs_vnops.c:570 vfs_lookup(ffff80003b806fd0) at vfs_lookup+0x11c sys/kern/vfs_lookup.c:-1 namei(ffff80003b806fd0) at namei+0x7ca sys/kern/vfs_lookup.c:250 unp_connect(ffff800010fca330,fffffd806671a500,ffff8000383f7cc0) at unp_connect+0x29d sys/kern/uipc_usrreq.c:872 uipc_dgram_send(ffff800010fca330,fffffd800ef8b100,fffffd806671a500,0) at uipc_dgram_send+0x163 sys/kern/uipc_usrreq.c:609 sosend(ffff800010fca330,fffffd806671a500,ffff80003b807258,0,0,e) at sosend+0x804 sys/kern/uipc_socket.c:-1 sendit(ffff8000383f7cc0,3,ffff80003b8073d8,e,ffff80003b807490) at sendit+0x5a5 sys/kern/uipc_syscalls.c:785 sys_sendmsg(ffff8000383f7cc0,ffff80003b807540,ffff80003b807490) at sys_sendmsg+0x246 sys/kern/uipc_syscalls.c:603 syscall(ffff80003b807540) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003b807540) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:746 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xb1dc48d10b0, count: -15 ddb{0}> show registers rdi 0 rsi 0 rbp 0xffff80003b806c50 rbx 0 rdx 0 rcx 0xffff8000383f7cc0 rax 0xffffffff837b5ff0 cpu_info_full_primary+0x1ff0 r8 0xffff80003b806b30 r9 0x8080808080808080 r10 0x2ded6884e7864655 r11 0x13917ef9c79a0310 r12 0xfffffd8003ef7680 r13 0xfffffd80046df2c8 r14 0x3 r15 0xffffffff833dadbe substchar+0xb292 rip 0xffffffff81d6b285 db_enter+0x25 cs 0x8 rflags 0x246 rsp 0xffff80003b806c40 ss 0x10 db_enter+0x25: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor) tid=431142 pid=73191 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=0xffff8000383f7790,0xffffffff838a2ac8 process=0xffff800035c409d0 user=0xffff80003b802000, vmspace=0xfffffd80781343e0 estcpu=36, cpticks=0, pctcpu=0.0, user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 67331 40174 95413 0 2 0 syz-executor 73191 149755 36961 0 7 0x1 syz-executor *73191 431142 36961 0 7 0x4000000 syz-executor 76802 484173 81573 0 2 0 syz-executor 76802 341939 81573 0 3 0x4000080 fsleep syz-executor 49874 143509 54289 60929 3 0x90 nanoslp syz-executor 49874 243268 54289 60929 3 0x4000090 kqsel syz-executor 49874 469281 54289 60929 3 0x4000090 fsleep syz-executor 39741 193482 1 0 3 0x82 nanoslp getty 54289 469154 77219 0 3 0x82 nanoslp syz-executor 36961 162970 77219 0 3 0x82 nanoslp syz-executor 95413 93434 77219 0 3 0x82 nanoslp syz-executor 42715 316375 0 0 3 0x14280 nfsidl nfsio 87945 45613 0 0 3 0x14280 nfsidl nfsio 44836 186619 0 0 3 0x14280 nfsidl nfsio 717 155332 0 0 3 0x14280 nfsidl nfsio 15680 36453 0 0 3 0x14280 nfsidl nfsio 59531 513354 0 0 3 0x14280 nfsidl nfsio 38490 58909 0 0 3 0x14280 nfsidl nfsio 80897 397133 0 0 3 0x14280 nfsidl nfsio 84135 46860 0 0 3 0x14280 nfsidl nfsio 69444 171683 0 0 3 0x14280 nfsidl nfsio 51038 337355 0 0 3 0x14280 nfsidl nfsio 17719 174762 0 0 3 0x14280 nfsidl nfsio 35975 177793 0 0 3 0x14280 nfsidl nfsio 58527 299704 0 0 3 0x14280 nfsidl nfsio 16531 5428 0 0 3 0x14280 nfsidl nfsio 6048 388538 0 0 3 0x14280 nfsidl nfsio 88209 238678 0 0 3 0x14280 nfsidl nfsio 99318 234999 0 0 3 0x14280 nfsidl nfsio 11611 469444 0 0 3 0x14280 nfsidl nfsio 12890 187881 0 0 3 0x14280 nfsidl nfsio 81573 351540 77219 0 3 0x82 nanoslp syz-executor 4474 447311 0 0 3 0x14200 bored sosplice 43275 22767 77219 0 3 0x82 wait syz-executor 31553 428065 77219 0 3 0x82 wait syz-executor 91560 113817 77219 0 3 0x82 wait syz-executor 98244 275821 77219 0 3 0x82 nanoslp syz-executor 77219 259259 1163 0 3 0x82 kqread syz-executor 1163 405397 32593 0 3 0x10008a sigsusp ksh 32593 137620 72961 0 3 0x98 kqread sshd-session 72961 385490 4752 0 3 0x92 kqread sshd-session 4752 464912 1 0 3 0x88 kqread sshd 26677 248123 75045 74 3 0x1100092 bpf pflogd 75045 480016 1 0 3 0x80 sbwait pflogd 45511 427792 62174 73 3 0x1100090 kqread syslogd 62174 448214 1 0 3 0x100082 sbwait syslogd 11143 89650 1 0 3 0x100080 kqread resolvd 53442 499298 41729 77 3 0x100092 kqread dhcpleased 57610 476422 41729 77 3 0x100092 kqread dhcpleased 41729 56640 1 0 3 0x80 kqread dhcpleased 35910 161177 0 0 3 0x14200 bored smr 2004 267053 0 0 2 0x14200 zerothread 31058 478360 0 0 3 0x14200 aiodoned aiodoned 44499 370919 0 0 3 0x14200 syncer update 44946 132530 0 0 3 0x14200 cleaner cleaner 68752 338948 0 0 3 0x14200 reaper reaper 65683 221607 0 0 3 0x14200 pgdaemon pagedaemon 93541 292134 0 0 3 0x14200 bored viomb 82309 508094 0 0 3 0x40014200 acpi0 acpi0 10385 514679 0 0 3 0x40014200 idle1 24984 147436 0 0 3 0x14200 bored softnet1 96294 112300 0 0 3 0x14200 bored softnet0 3707 35835 0 0 3 0x14200 bored systqmp 77998 38528 0 0 3 0x14200 bored systq 78911 271536 0 0 3 0x14200 tmoslp softclockmp 43375 169265 0 0 3 0x40014200 tmoslp softclock 68322 239638 0 0 3 0x40014200 idle0 1 95600 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 73191 (syz-executor) thread 0xffff8000383f7cc0 (431142) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff83929028) #0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160 #1 unp_connect+0x28c sys/kern/uipc_usrreq.c:872 #2 uipc_dgram_send+0x163 sys/kern/uipc_usrreq.c:609 #3 sosend+0x804 sys/kern/uipc_socket.c:-1 #4 sendit+0x5a5 sys/kern/uipc_syscalls.c:785 #5 sys_sendmsg+0x246 sys/kern/uipc_syscalls.c:603 #6 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #6 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:746 #7 Xsyscall+0x128 exclusive rwlock sbufsnd r = 0 (0xffff800010fca518) #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 sblock+0xb6 sys/kern/uipc_socket2.c:536 #3 sosend+0x2e9 sys/kern/uipc_socket.c:631 #4 sendit+0x5a5 sys/kern/uipc_syscalls.c:785 #5 sys_sendmsg+0x246 sys/kern/uipc_syscalls.c:603 #6 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #6 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:746 #7 Xsyscall+0x128 ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10227 11095K 12364K 166960K 13674 0 pcb 19 16K 17K 166960K 316 0 rtable 218 10K 10K 166960K 504 0 pf 35 17K 81K 166960K 136 0 ifaddr 40 7K 8K 166960K 105 0 ifgroup 51 2K 2K 166960K 157 0 sysctl 4 1K 9K 166960K 13 0 counters 66 36K 37K 166960K 176 0 ioctlops 0 0K 4K 166960K 1765 0 iov 0 0K 24K 166960K 93 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1485 93K 93K 166960K 2535 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 616K 624K 166960K 22 0 VM map 2 1K 1K 166960K 2 0 sem 12 0K 0K 166960K 48 0 dirhash 12 2K 3K 166960K 39 0 ACPI 1692 195K 286K 166960K 12470 0 file desc 18 65K 240K 166960K 1280 0 sigio 0 0K 0K 166960K 17 0 proc 72 115K 180K 166960K 793 0 subproc 72 4K 4K 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 167 0 in_multi 82 6K 7K 166960K 182 0 ether_multi 1 0K 0K 166960K 4 0 mrt 1 0K 0K 166960K 7 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 235 1049K 1049K 166960K 235 0 exec 0 0K 1K 166960K 613 0 fusefs mount 1 32K 32K 166960K 1 0 pfkey data 0 0K 0K 166960K 7 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 251 168K 182K 166960K 13073 0 UVM aobj 102 3K 3K 166960K 108 0 pinsyscall 43 86K 102K 166960K 2508 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 0 0K 0K 166960K 68 0 NDP 11 0K 2K 166960K 71 0 temp 72 8650K 8715K 166960K 50309 0 kqueue 13 20K 30K 166960K 237 0 SYN cache 2 8K 16K 166960K 3 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 120 169 0 165 3 2 1 3 0 8 0 rtentry 176 181 0 92 5 0 5 5 0 8 0 unpcb 144 855 0 837 9 7 2 6 0 8 1 syncache 336 10 0 10 3 2 1 1 0 8 1 tcpqe 32 1 0 1 1 1 0 1 0 8 0 tcpcb 736 438 0 431 10 9 1 7 0 8 0 arp 136 21 0 9 1 0 1 1 0 8 0 inpcb 328 1345 0 1330 20 13 7 7 0 8 5 nd6 152 40 0 17 1 0 1 1 0 8 0 pkpcb 40 19 0 19 3 2 1 1 0 8 1 kcovpl 48 13 0 5 1 0 1 1 0 8 0 ppxss 1192 40 0 40 3 2 1 1 0 8 1 pppxif 1504 7 0 7 2 1 1 1 0 8 1 pffrag 232 7 0 1 1 0 1 1 0 482 0 pffrnode 88 7 0 1 1 0 1 1 0 8 0 pffrent 40 15 0 9 1 0 1 1 0 8 0 pfosfp 40 1431 0 1007 5 0 5 5 0 8 0 pfosfpen 112 1431 0 715 21 0 21 21 0 8 0 pftag 88 1 0 0 1 0 1 1 0 8 0 pfqueue 320 1 0 0 1 0 1 1 0 8 0 pfstitem 24 99 0 22 1 0 1 1 0 8 0 pfstkey 128 101 0 24 3 0 3 3 0 8 0 pfstate 384 98 0 23 8 0 8 8 0 8 0 pfrule 1344 22 0 16 2 1 1 2 0 8 0 rttmr 136 1 0 1 1 0 1 1 0 8 1 art_heap8 4096 4 0 0 4 0 4 4 0 8 0 art_heap4 256 854 0 420 37 4 33 33 0 8 1 art_table 40 858 0 420 6 0 6 6 0 8 0 art_node 32 179 0 100 1 0 1 1 0 8 0 sysvmsgpl 40 10 0 8 1 0 1 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 44 0 34 1 0 1 1 0 8 0 shmpl 112 105 0 6 3 0 3 3 0 8 0 dirhash 1024 35 0 18 3 0 3 3 0 8 0 dino2pl 256 3589 0 2085 95 0 95 95 0 8 0 ffsino 296 3589 0 2085 117 0 117 117 0 8 0 nchpl 144 5287 0 3581 64 0 64 64 0 8 0 rtmask 32 7 0 7 3 2 1 1 0 8 1 uvmvnodes 80 4265 0 0 88 0 88 88 0 8 0 vnodes 216 4265 0 0 237 0 237 237 0 8 0 namei 1024 19395 0 19394 3 2 1 2 0 8 0 percpumem 16 103 0 55 1 0 1 1 0 8 0 kstatmem 264 90 0 66 2 0 2 2 0 8 0 scsiplug 72 2 0 2 1 1 0 1 0 8 0 scxspl 216 36116 0 36116 10 9 1 8 1 8 1 plimitpl 152 273 0 255 1 0 1 1 0 8 0 sigapl 424 1581 0 1512 9 1 8 8 0 8 0 knotepl 120 561 0 0 17 0 17 17 0 8 0 kqueuepl 224 521 0 509 10 8 2 5 0 8 1 pipepl 344 231 0 203 3 0 3 3 0 8 0 fdescpl 528 1544 0 1512 3 0 3 3 0 8 0 filepl 160 10039 0 9808 30 17 13 18 0 8 1 lockfpl 104 614 0 612 2 1 1 2 0 8 0 lockfspl 48 279 0 277 1 0 1 1 0 8 0 sessionpl 144 33 0 25 1 0 1 1 0 8 0 pgrppl 48 59 0 43 1 0 1 1 0 8 0 ucredpl 104 1363 0 1349 1 0 1 1 0 8 0 zombiepl 144 1606 0 1602 2 1 1 1 0 8 0 processpl 1232 1581 0 1512 7 1 6 6 0 8 0 procpl 664 3466 0 3393 8 0 8 8 0 8 0 sosppl 168 15 0 15 3 2 1 1 0 8 1 sockpl 752 2477 0 2440 32 22 10 16 0 8 5 mcl64k 65536 5 0 0 1 0 1 1 0 8 0 mcl16k 16384 1 0 0 1 0 1 1 0 8 0 mcl12k 12288 2 0 0 1 0 1 1 0 8 0 mcl9k 9216 1 0 0 1 0 1 1 0 8 0 mcl8k 8192 3 0 0 1 0 1 1 0 8 0 mcl4k 4096 115 0 0 15 0 15 15 0 8 0 mcl2k2 2112 2 0 0 1 0 1 1 0 8 0 mcl2k 2048 25 0 0 4 0 4 4 0 8 0 mtagpl 96 106 0 0 3 0 3 3 0 8 0 mbufpl 256 381 0 0 24 0 24 24 0 8 0 bufpl 280 14868 0 8724 440 0 440 440 0 8 0 anonpl 32 14304 0 0 116 0 116 116 0 246 0 amapchunkpl 152 43478 0 42947 39 12 27 29 0 158 2 amappl16 200 5675 0 5636 60 45 15 35 0 8 7 amappl15 192 3 0 3 1 1 0 1 0 8 0 amappl14 184 134 0 122 1 0 1 1 0 8 0 amappl13 176 9 0 9 1 1 0 1 0 8 0 amappl12 168 2268 0 2237 4 2 2 3 0 8 0 amappl11 160 51 0 36 1 0 1 1 0 8 0 amappl10 152 23 0 23 1 1 0 1 0 8 0 amappl9 144 254 0 252 1 0 1 1 0 8 0 amappl8 136 24 0 22 1 0 1 1 0 8 0 amappl7 128 126 0 113 1 0 1 1 0 8 0 amappl6 120 231 0 228 1 0 1 1 0 8 0 amappl5 112 149 0 138 1 0 1 1 0 8 0 amappl4 104 325 0 304 1 0 1 1 0 8 0 amappl3 96 7669 0 7563 4 1 3 3 0 8 0 amappl2 88 1826 0 1747 2 0 2 2 0 8 0 amappl1 80 14275 0 13666 17 2 15 15 0 8 0 amappl 88 12102 0 11923 5 0 5 5 0 92 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma1024 1024 2 0 1 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 7 0 7 1 1 0 1 0 8 0 dma16 16 18 0 17 1 0 1 1 0 8 0 aobjpl 72 107 0 6 2 0 2 2 0 8 0 uaddrrnd 24 1544 0 1512 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 1544 0 1512 1 0 1 1 0 8 0 vmmpekpl 168 13547 0 13493 3 0 3 3 0 8 0 vmmpepl 168 103155 0 101074 118 16 102 118 0 357 1 vmsppl 488 1543 0 1512 6 1 5 5 0 8 0 rwobjpl 80 33885 0 28549 112 0 112 112 0 8 2 pdppl 4096 3096 0 3024 116 42 74 86 0 8 2 pvpl 32 24469 0 0 199 1 198 198 0 265 0 pmappl 256 1543 0 1512 3 0 3 3 0 8 0 extentpl 40 45 0 27 1 0 1 1 0 8 0 phpool 112 323 0 61 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:438 witness_checkorder(fffffd806e0bcf00,9,0) at witness_checkorder+0x10b9 sys/kern/subr_witness.c:-1 rw_do_enter_write(fffffd806e0bcee8,1) at rw_do_enter_write+0xba sys/kern/kern_rwlock.c:234 rrw_enter(fffffd806e0bcee8,1) at rrw_enter+0xc6 sys/kern/kern_rwlock.c:621 VOP_LOCK(fffffd807268acb8,2001) at VOP_LOCK+0xa3 sys/kern/vfs_vops.c:527 vn_lock(fffffd807268acb8,2001) at vn_lock+0xa4 sys/kern/vfs_vnops.c:570 vfs_lookup(ffff80003b806fd0) at vfs_lookup+0x11c sys/kern/vfs_lookup.c:-1 namei(ffff80003b806fd0) at namei+0x7ca sys/kern/vfs_lookup.c:250 unp_connect(ffff800010fca330,fffffd806671a500,ffff8000383f7cc0) at unp_connect+0x29d sys/kern/uipc_usrreq.c:872 uipc_dgram_send(ffff800010fca330,fffffd800ef8b100,fffffd806671a500,0) at uipc_dgram_send+0x163 sys/kern/uipc_usrreq.c:609 sosend(ffff800010fca330,fffffd806671a500,ffff80003b807258,0,0,e) at sosend+0x804 sys/kern/uipc_socket.c:-1 sendit(ffff8000383f7cc0,3,ffff80003b8073d8,e,ffff80003b807490) at sendit+0x5a5 sys/kern/uipc_syscalls.c:785 sys_sendmsg(ffff8000383f7cc0,ffff80003b807540,ffff80003b807490) at sys_sendmsg+0x246 sys/kern/uipc_syscalls.c:603 syscall(ffff80003b807540) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003b807540) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:746 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xb1dc48d10b0, count: -15 ddb{0}> machine ddbcpu 1 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp ddb{1}> trace x86_ipi_db(ffff8000299fdff0) 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 __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x2c kd_curproc sys/dev/kcov.c:584 [inline] __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x2c sys/dev/kcov.c:153 __mp_lock(ffffffff83928e20) at __mp_lock+0x1a3 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff83928e20) at __mp_lock+0x1a3 sys/kern/kern_lock.c:165 ktrsysret(ffff8000383f6d30,53,0,ffff800035c5f7e0) at ktrsysret+0xde ktrwrite2 sys/kern/kern_ktrace.c:-1 [inline] ktrsysret(ffff8000383f6d30,53,0,ffff800035c5f7e0) at ktrsysret+0xde sys/kern/kern_ktrace.c:209 syscall(ffff800035c5f890) at syscall+0xa50 mi_syscall_return sys/sys/syscall_mi.h:204 [inline] syscall(ffff800035c5f890) at syscall+0xa50 sys/arch/amd64/amd64/trap.c:767 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x71a9a8605b40, count: -8