panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_synch.c", line 951
Stopped at db_enter+0x25: addq $0x8,%rsp
TID PID UID PRFLAGS PFLAGS CPU COMMAND
3293 71961 0 0x10000002 0x1 1 syz-executor
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff83372c99) at panic+0x1e5 sys/kern/subr_prf.c:198
__assert(ffffffff833acf1b,ffffffff833bd15d,3b7,ffffffff833e70b3) at __assert+0x29 sys/kern/subr_prf.c:-1
refcnt_finalize(ffff80002a33f508,ffffffff833691a2) at refcnt_finalize+0x1db sys/kern/kern_synch.c:952
pppx_if_destroy(0,ffff80002a33f500) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794
pppxclose(205b9a,2,2000,ffff80003c482d30) at pppxclose+0xa0 sys/net/if_pppx.c:541
spec_close(ffff80002a3e1220) at spec_close+0x417 sys/kern/spec_vnops.c:-1
VOP_CLOSE(fffffd8065f2e7d0,2,fffffd80097fb3a8,ffff80003c482d30) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156
vn_closefile(fffffd805d329ca8,ffff80003c482d30) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd805d329ca8,ffff80003c482d30) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615
fdrop(fffffd805d329ca8,ffff80003c482d30) at fdrop+0x121 sys/kern/kern_descrip.c:1267
closef(fffffd805d329ca8,ffff80003c482d30) at closef+0x192 sys/kern/kern_descrip.c:1251
fdfree(ffff80003c482d30) at fdfree+0x116 sys/kern/kern_descrip.c:1182
exit1(ffff80003c482d30,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215
sys_exit(ffff80003c482d30,ffff80002a3e1590,ffff80002a3e14e0) at sys_exit+0x1a sys/kern/kern_exit.c:-1
end trace frame: 0xffff80002a3e1580, count: 0
https://www.openbsd.org/ddb.html describes the minimum info required in bug
reports. Insufficient info makes it difficult to find and fix bugs.
ddb{0}>
ddb{0}> set $lines = 0
ddb{0}> set $maxwidth = 0
ddb{0}> show panic
*cpu0: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_synch.c", line 951
ddb{0}> trace
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff83372c99) at panic+0x1e5 sys/kern/subr_prf.c:198
__assert(ffffffff833acf1b,ffffffff833bd15d,3b7,ffffffff833e70b3) at __assert+0x29 sys/kern/subr_prf.c:-1
refcnt_finalize(ffff80002a33f508,ffffffff833691a2) at refcnt_finalize+0x1db sys/kern/kern_synch.c:952
pppx_if_destroy(0,ffff80002a33f500) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794
pppxclose(205b9a,2,2000,ffff80003c482d30) at pppxclose+0xa0 sys/net/if_pppx.c:541
spec_close(ffff80002a3e1220) at spec_close+0x417 sys/kern/spec_vnops.c:-1
VOP_CLOSE(fffffd8065f2e7d0,2,fffffd80097fb3a8,ffff80003c482d30) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156
vn_closefile(fffffd805d329ca8,ffff80003c482d30) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd805d329ca8,ffff80003c482d30) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615
fdrop(fffffd805d329ca8,ffff80003c482d30) at fdrop+0x121 sys/kern/kern_descrip.c:1267
closef(fffffd805d329ca8,ffff80003c482d30) at closef+0x192 sys/kern/kern_descrip.c:1251
fdfree(ffff80003c482d30) at fdfree+0x116 sys/kern/kern_descrip.c:1182
exit1(ffff80003c482d30,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215
sys_exit(ffff80003c482d30,ffff80002a3e1590,ffff80002a3e14e0) at sys_exit+0x1a sys/kern/kern_exit.c:-1
syscall(ffff80002a3e1590) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80002a3e1590) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:748
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x771b783877d0, count: -16
ddb{0}> show registers
rdi 0
rsi 0x1
rbp 0xffff80002a3e0ff0
rbx 0xffffffff8380eddf cpu_info_full_primary+0x2ddf
rdx 0
rcx 0xffff80003c482d30
rax 0xffffffff8380dff0 cpu_info_full_primary+0x1ff0
r8 0x101010101010101
r9 0x8080808080808080
r10 0x9c98d92f3cceb4f2
r11 0x6793e5472fc126b8
r12 0xffffffff8380ebe0 cpu_info_full_primary+0x2be0
r13 0
r14 0
r15 0x1
rip 0xffffffff82fcb0c5 db_enter+0x25
cs 0x8
rflags 0x246
rsp 0xffff80002a3e0fe0
ss 0x10
db_enter+0x25: addq $0x8,%rsp
ddb{0}> show proc
PROC (syz-executor) tid=254615 pid=71222 tcnt=0 stat=onproc
flags process=1008<EXITING,SINGLEEXIT> proc=2000<WEXIT>
runpri=32, usrpri=86, slppri=32, nice=20
wchan=0x0, wmesg=, ps_single=0xffff80003c482d30 scnt=-1 ecnt=1
forw=0xffffffffffffffff, list=0xffff80002a2c0fb0,0xffff80002a2c02c8
process=0xffff80003c4e5d68 user=0xffff80002a3dc000, vmspace=0xfffffd806c2ea028
estcpu=36, cpticks=7, pctcpu=0.0, user=0, sys=2, intr=0
ddb{0}> ps
PID TID PPID UID S FLAGS WAIT COMMAND
58392 336687 70075 0 2 0 syz-executor
51962 197079 2511 0 2 0 syz-executor
51962 327265 2511 0 3 0x4000080 fsleep syz-executor
51962 438189 2511 0 2 0x4000000 syz-executor
10446 252015 17588 0 2 0 syz-executor
10446 220968 17588 0 2 0x4000000 syz-executor
10446 12136 17588 0 2 0x4000000 syz-executor
81888 150882 85281 0 2 0 syz-executor
81888 510435 85281 0 3 0x4000080 sbwait syz-executor
81888 75575 85281 0 3 0x4000080 fsleep syz-executor
3164 450645 54456 0 3 0x80 nanoslp syz-executor
3164 424178 54456 0 3 0x4000080 nanoslp syz-executor
70075 318061 77712 0 2 0xc82 syz-executor
29263 215645 77712 0 3 0x82 nanoslp syz-executor
30764 362677 1 0 3 0x100083 ttyin getty
17588 384171 77712 0 3 0x82 nanoslp syz-executor
54456 462007 77712 0 3 0x82 nanoslp syz-executor
76636 433092 0 0 3 0x14200 bored sosplice
2511 509366 77712 0 3 0x82 nanoslp syz-executor
71961 3293 77712 0 7 0x10000003 syz-executor
4390 376539 77712 0 2 0xc82 syz-executor
85281 497905 77712 0 2 0xc82 syz-executor
77712 42896 64069 0 3 0x82 kqread syz-executor
64069 50007 93074 0 3 0x10008a sigsusp ksh
93074 238271 33566 0 3 0x98 kqread sshd-session
33566 350297 94758 0 3 0x92 kqread sshd-session
94758 408918 1 0 3 0x88 kqread sshd
87483 256586 38492 74 3 0x1100092 bpf pflogd
38492 18884 1 0 3 0x80 sbwait pflogd
15071 26749 43554 73 3 0x1100090 kqread syslogd
43554 26054 1 0 3 0x100082 sbwait syslogd
60490 475024 1 0 3 0x100080 kqread resolvd
14930 382866 61161 77 3 0x100092 kqread dhcpleased
54795 77055 61161 77 2 0x100012 dhcpleased
61161 407032 1 0 3 0x80 kqread dhcpleased
47091 336412 0 0 3 0x14200 bored smr
2955 145651 0 0 2 0x14200 zerothread
90575 101310 0 0 3 0x14200 aiodoned aiodoned
17827 222665 0 0 3 0x14200 syncer update
37093 175383 0 0 3 0x14200 cleaner cleaner
92344 100451 0 0 3 0x14200 reaper reaper
9725 356362 0 0 3 0x14200 pgdaemon pagedaemon
90563 294071 0 0 3 0x14200 bored viomb
92290 158040 0 0 3 0x40014200 acpi0 acpi0
28429 496356 0 0 3 0x40014200 idle1
25723 523449 0 0 3 0x14200 bored softnet7
16476 310889 0 0 3 0x14200 bored softnet6
87978 85137 0 0 3 0x14200 bored softnet5
97964 73848 0 0 3 0x14200 bored softnet4
20039 187208 0 0 3 0x14200 bored softnet3
458 22418 0 0 3 0x14200 bored softnet2
18088 438066 0 0 3 0x14200 bored softnet1
15552 418314 0 0 3 0x14200 bored softnet0
59517 191637 0 0 3 0x14200 smrbar systqmp
88209 70005 0 0 3 0x14200 bored systq
18771 445029 0 0 3 0x14200 tmoslp softclockmp
97988 125087 0 0 3 0x40014200 tmoslp softclock
6232 283094 0 0 3 0x40014200 idle0
1 455629 0 0 3 0x82 wait init
0 0 -1 0 3 0x10010200 scheduler swapper
ddb{0}> show all locks
Process 81888 (syz-executor) thread 0xffff80002a2c1ca8 (510435)
exclusive rwlock sbufrcv r = 0 (0xffff800001547928)
#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 soreceive+0x27d sys/kern/uipc_socket.c:870
#4 recvit+0x40b sys/kern/uipc_syscalls.c:1072
#5 sys_recvmmsg+0x410 sys/kern/uipc_syscalls.c:963
#6 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#6 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:748
#7 Xsyscall+0x128
Process 59517 (systqmp) thread 0xffff8000ffffe000 (191637)
shared rwlock systqmp r = 0 (0xffffffff8380feb8)
#0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1 taskq_thread+0x12a sys/kern/kern_task.c:442
#2 proc_trampoline+0x10
ddb{0}> show malloc
Type InUse MemUse HighUse Limit Requests Type Lim
devbuf 10244 11050K 11746K 166960K 14077 0
pcb 17 19K 33K 166960K 612 0
rtable 188 12K 13K 166960K 1027 0
pf 41 18K 82K 166960K 253 0
ifaddr 38 6K 8K 166960K 251 0
ifgroup 64 2K 3K 166960K 282 0
sysctl 4 1K 9K 166960K 19 0
counters 74 37K 38K 166960K 300 0
ioctlops 0 0K 4K 166960K 1949 0
iov 1 4K 32K 166960K 403 0
mount 1 1K 1K 166960K 1 0
log 0 0K 0K 166960K 4 0
vnodes 1515 95K 96K 166960K 3869 0
UFS quota 1 32K 32K 166960K 1 0
UFS mount 5 36K 36K 166960K 5 0
shm 5 17K 21K 166960K 67 0
VM map 2 1K 1K 166960K 2 0
sem 12 0K 1K 166960K 123 0
dirhash 12 2K 3K 166960K 78 0
ACPI 1692 195K 286K 166960K 12470 0
file desc 17 61K 240K 166960K 2773 0
sigio 0 0K 0K 166960K 161 0
proc 72 115K 164K 166960K 1275 0
subproc 72 4K 4K 166960K 216 0
NFS srvsock 1 0K 0K 166960K 1 0
NFS daemon 1 16K 16K 166960K 1 0
ip_moptions 0 0K 0K 166960K 298 0
in_multi 67 5K 7K 166960K 353 0
ether_multi 1 0K 0K 166960K 18 0
mrt 0 0K 0K 166960K 17 0
ISOFS mount 1 32K 32K 166960K 1 0
MSDOSFS mount 1 16K 16K 166960K 1 0
ttys 175 784K 784K 166960K 175 0
exec 0 0K 1K 166960K 978 0
fusefs mount 1 32K 32K 166960K 1 0
pfkey data 0 0K 0K 166960K 4 0
tdb 3 0K 0K 166960K 3 0
VM swap 8 62K 64K 166960K 10 0
UVM amap 246 170K 185K 166960K 26052 0
UVM aobj 60 2K 3K 166960K 63 0
pinsyscall 42 84K 104K 166960K 4270 0
memdesc 1 4K 4K 166960K 1 0
crypto data 1 1K 1K 166960K 1 0
ip6_options 0 0K 0K 166960K 134 0
NDP 16 0K 2K 166960K 134 0
temp 82 8648K 8904K 166960K 126864 0
kqueue 14 22K 32K 166960K 464 0
SYN cache 2 0K 16K 166960K 4 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 120 416 0 413 5 4 1 3 0 8 0
rtentry 176 383 0 321 5 0 5 5 0 8 0
unpcb 144 1965 0 1944 19 15 4 6 0 8 3
syncache 336 20 0 20 6 5 1 1 0 8 1
tcpqe 32 6 0 6 5 5 0 1 0 8 0
tcpcb 736 1082 0 1074 26 19 7 7 0 8 5
arp 128 46 0 37 1 0 1 1 0 8 0
inpcb 328 3345 0 3334 50 43 7 18 0 8 5
nd6 144 57 0 47 1 0 1 1 0 8 0
pkpcb 40 27 0 26 6 5 1 1 0 8 0
kcovpl 48 24 0 16 1 0 1 1 0 8 0
ppxss 1192 83 0 82 4 3 1 1 0 8 0
pppxif 1504 12 0 11 5 4 1 1 0 8 0
pfstscr 40 2 0 1 1 0 1 1 0 8 0
pffrag 232 18 0 9 1 0 1 1 0 482 0
pffrnode 88 16 0 7 1 0 1 1 0 8 0
pffrent 40 26 0 17 1 0 1 1 0 8 0
pfosfp 40 1428 0 1428 5 5 0 5 0 8 0
pfosfpen 112 1428 0 1428 21 21 0 21 0 8 0
pfrktable 1344 1 0 1 1 1 0 1 0 8 0
pftag 88 1 0 0 1 0 1 1 0 8 0
pfstitem 24 216 0 108 1 0 1 1 0 8 0
pfstkey 128 222 0 114 4 0 4 4 0 8 0
pfstate 384 218 0 111 13 2 11 11 0 8 0
pfrule 1344 32 0 27 2 1 1 2 0 8 0
rttmr 136 5 0 5 4 4 0 1 0 8 0
art_heap8 4096 4 0 1 4 1 3 4 0 8 0
art_heap4 256 1378 0 1021 39 14 25 31 0 8 1
art_table 40 1382 0 1022 5 0 5 5 0 8 0
art_node 32 376 0 321 2 1 1 2 0 8 0
sysvmsgpl 40 14 0 10 1 0 1 1 0 8 0
semupl 112 1 0 1 1 1 0 1 0 8 0
semapl 112 119 0 109 1 0 1 1 0 8 0
shmpl 112 60 0 3 2 0 2 2 0 8 0
dirhash 1024 61 0 44 3 0 3 3 0 8 0
dino2pl 256 6212 0 4676 97 0 97 97 0 8 0
ffsino 296 6212 0 4676 119 0 119 119 0 8 0
nchpl 144 9623 0 7863 66 0 66 66 0 8 0
rtmask 32 23 0 23 5 4 1 1 0 8 1
uvmvnodes 80 5926 0 0 121 0 121 121 0 8 0
vnodes 216 5926 0 0 330 0 330 330 0 8 0
namei 1024 35580 0 35580 6 5 1 3 0 8 1
percpumem 16 165 0 113 1 0 1 1 0 8 0
kstatmem 264 178 0 144 4 1 3 3 0 8 0
acpiwqpl 32 1 0 1 1 0 1 1 1 8 1
scsiplug 72 11 0 11 8 7 1 1 0 8 1
scxspl 216 61692 0 61692 15 13 2 8 1 8 2
plimitpl 152 597 0 580 1 0 1 1 0 8 0
sigapl 424 3012 0 2957 9 1 8 9 0 8 0
knotepl 120 588 0 0 18 0 18 18 0 8 0
kqueuepl 224 1022 0 1011 15 14 1 5 0 8 0
pipepl 344 479 0 452 16 13 3 9 0 8 0
fdescpl 528 2959 0 2928 3 0 3 3 0 8 0
filepl 160 20164 0 19945 37 24 13 19 0 8 2
lockfpl 104 1369 0 1367 6 5 1 2 0 8 0
lockfspl 48 459 0 457 1 0 1 1 0 8 0
sessionpl 144 55 0 46 1 0 1 1 0 8 0
pgrppl 48 113 0 96 1 0 1 1 0 8 0
ucredpl 104 3143 0 3129 1 0 1 1 0 8 0
zombiepl 144 4079 0 4076 1 0 1 1 0 8 0
processpl 1248 3012 0 2957 6 0 6 6 0 8 0
procpl 664 7123 0 7061 8 1 7 8 0 8 0
sosppl 168 14 0 14 5 4 1 1 0 8 1
sockpl 752 5943 0 5906 88 77 11 27 0 8 6
mcl64k 65536 18 0 0 3 0 3 3 0 8 0
mcl16k 16384 9 0 0 2 0 2 2 0 8 0
mcl12k 12288 1 0 0 1 0 1 1 0 8 0
mcl9k 9216 3 0 0 1 0 1 1 0 8 0
mcl8k 8192 9 0 0 2 0 2 2 0 8 0
mcl4k 4096 125 0 0 16 0 16 16 0 8 0
mcl2k2 2112 1 0 0 1 0 1 1 0 8 0
mcl2k 2048 27 0 0 4 0 4 4 0 8 0
mtagpl 96 7 0 0 1 0 1 1 0 8 0
mbufpl 256 377 0 0 21 0 21 21 0 8 0
bufpl 280 25227 0 19084 440 1 439 440 0 8 0
anonpl 32 16024 0 0 130 1 129 129 0 246 0
amapchunkpl 152 90919 0 90342 59 24 35 35 0 158 9
amappl16 200 9984 0 9920 57 36 21 31 0 8 5
amappl15 192 1 0 1 1 1 0 1 0 8 0
amappl14 184 176 0 163 1 0 1 1 0 8 0
amappl13 176 12 0 12 1 1 0 1 0 8 0
amappl12 168 3893 0 3862 4 1 3 3 0 8 0
amappl11 160 52 0 37 1 0 1 1 0 8 0
amappl10 152 6 0 5 1 0 1 1 0 8 0
amappl9 144 252 0 252 1 1 0 1 0 8 0
amappl8 136 26 0 22 1 0 1 1 0 8 0
amappl7 128 177 0 164 1 0 1 1 0 8 0
amappl6 120 349 0 345 1 0 1 1 0 8 0
amappl5 112 190 0 180 1 0 1 1 0 8 0
amappl4 104 383 0 362 1 0 1 1 0 8 0
amappl3 96 17963 0 17852 5 1 4 4 0 8 0
amappl2 88 972 0 910 2 0 2 2 0 8 0
amappl1 80 23045 0 22438 15 0 15 15 0 8 0
amappl 88 24664 0 24493 5 0 5 5 0 92 0
dma32768 32768 1 0 1 1 1 0 1 0 8 0
dma4096 4096 2 0 2 2 2 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 3 3 0 1 0 8 0
dma64 64 7 0 7 2 1 1 1 0 8 1
dma32 32 7 0 7 1 1 0 1 0 8 0
dma16 16 20 0 19 1 0 1 1 0 8 0
aobjpl 72 62 0 3 2 0 2 2 0 8 0
uaddrrnd 24 2959 0 2928 1 0 1 1 0 8 0
uaddrbest 32 2 0 0 1 0 1 1 0 8 0
uaddr 24 2959 0 2928 1 0 1 1 0 8 0
vmmpekpl 168 24294 0 24246 3 0 3 3 0 8 0
vmmpepl 168 194473 0 192421 127 16 111 117 0 357 6
vmsppl 488 2958 0 2928 6 1 5 5 0 8 0
rwobjpl 80 57974 0 51005 155 4 151 154 0 8 3
pdppl 4096 5925 0 5856 129 56 73 85 0 8 4
pvpl 32 25925 0 0 211 2 209 209 0 265 0
pmappl 256 2958 0 2928 3 0 3 3 0 8 0
extentpl 40 45 0 27 1 0 1 1 0 8 0
phpool 112 366 0 104 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
panic(ffffffff83372c99) at panic+0x1e5 sys/kern/subr_prf.c:198
__assert(ffffffff833acf1b,ffffffff833bd15d,3b7,ffffffff833e70b3) at __assert+0x29 sys/kern/subr_prf.c:-1
refcnt_finalize(ffff80002a33f508,ffffffff833691a2) at refcnt_finalize+0x1db sys/kern/kern_synch.c:952
pppx_if_destroy(0,ffff80002a33f500) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794
pppxclose(205b9a,2,2000,ffff80003c482d30) at pppxclose+0xa0 sys/net/if_pppx.c:541
spec_close(ffff80002a3e1220) at spec_close+0x417 sys/kern/spec_vnops.c:-1
VOP_CLOSE(fffffd8065f2e7d0,2,fffffd80097fb3a8,ffff80003c482d30) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156
vn_closefile(fffffd805d329ca8,ffff80003c482d30) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline]
vn_closefile(fffffd805d329ca8,ffff80003c482d30) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615
fdrop(fffffd805d329ca8,ffff80003c482d30) at fdrop+0x121 sys/kern/kern_descrip.c:1267
closef(fffffd805d329ca8,ffff80003c482d30) at closef+0x192 sys/kern/kern_descrip.c:1251
fdfree(ffff80003c482d30) at fdfree+0x116 sys/kern/kern_descrip.c:1182
exit1(ffff80003c482d30,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215
sys_exit(ffff80003c482d30,ffff80002a3e1590,ffff80002a3e14e0) at sys_exit+0x1a sys/kern/kern_exit.c:-1
syscall(ffff80002a3e1590) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80002a3e1590) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:748
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x771b783877d0, count: -16
ddb{0}> machine ddbcpu 1
Stopped at x86_ipi_db+0x27: addq $0x8,%rsp
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
__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(ffffffff838b0ba8) at __mp_lock+0x1a3 __mp_lock_spin sys/kern/kern_lock.c:134 [inline]
__mp_lock(ffffffff838b0ba8) at __mp_lock+0x1a3 sys/kern/kern_lock.c:165
ktrsysret(ffff8000ffff22a8,5b,4,ffff80002a3bda70) at ktrsysret+0xde ktrwrite2 sys/kern/kern_ktrace.c:-1 [inline]
ktrsysret(ffff8000ffff22a8,5b,4,ffff80002a3bda70) at ktrsysret+0xde sys/kern/kern_ktrace.c:209
syscall(ffff80002a3bdb20) at syscall+0xa50 mi_syscall_return sys/sys/syscall_mi.h:204 [inline]
syscall(ffff80002a3bdb20) at syscall+0xa50 sys/arch/amd64/amd64/trap.c:769
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7ee06028ae00, count: 7
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
__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(ffffffff838b0ba8) at __mp_lock+0x1a3 __mp_lock_spin sys/kern/kern_lock.c:134 [inline]
__mp_lock(ffffffff838b0ba8) at __mp_lock+0x1a3 sys/kern/kern_lock.c:165
ktrsysret(ffff8000ffff22a8,5b,4,ffff80002a3bda70) at ktrsysret+0xde ktrwrite2 sys/kern/kern_ktrace.c:-1 [inline]
ktrsysret(ffff8000ffff22a8,5b,4,ffff80002a3bda70) at ktrsysret+0xde sys/kern/kern_ktrace.c:209
syscall(ffff80002a3bdb20) at syscall+0xa50 mi_syscall_return sys/sys/syscall_mi.h:204 [inline]
syscall(ffff80002a3bdb20) at syscall+0xa50 sys/arch/amd64/amd64/trap.c:769
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7ee06028ae00, count: -8