panic: kernel diagnostic assertion "curproc->p_kd == NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/dev/kcov.c", line 519
Stopped at db_enter+0x18: addq $0x8,%rsp
TID PID UID PRFLAGS PFLAGS CPU COMMAND
374416 74252 0 0x12 0x40 0K sshd
*102222 78585 0 0x14000 0x200 1 softnet
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff823bf498) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242d3f9,ffffffff8242c702,207,ffffffff823d1f6e) at __assert+0x2b sys/kern/subr_prf.c:162
kcov_remote_enter(0,ffff800020eb4bd8) at kcov_remote_enter+0x155 sys/dev/kcov.c:519
taskq_thread(ffff80000002c000) at taskq_thread+0xd9 sys/kern/kern_task.c:447
end trace frame: 0x0, count: 10
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{1}>
ddb{1}> set $lines = 0
ddb{1}> set $maxwidth = 0
ddb{1}> show panic
kernel diagnostic assertion "curproc->p_kd == NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/dev/kcov.c", line 519
ddb{1}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff823bf498) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242d3f9,ffffffff8242c702,207,ffffffff823d1f6e) at __assert+0x2b sys/kern/subr_prf.c:162
kcov_remote_enter(0,ffff800020eb4bd8) at kcov_remote_enter+0x155 sys/dev/kcov.c:519
taskq_thread(ffff80000002c000) at taskq_thread+0xd9 sys/kern/kern_task.c:447
end trace frame: 0x0, count: -5
ddb{1}> show registers
rdi 0
rsi 0x1
rbp 0xffff800020db94a0
rbx 0xffff800020db94b0
rdx 0x8b
rcx 0x2
rax 0x1
r8 0xffff800020db9460
r9 0xffffffff8140d116 kprintf+0x146
r10 0x1
r11 0x9d8807188bb17d8b
r12 0x3000000008
r13 0xffff800020db9550
r14 0x100
r15 0x1
rip 0xffffffff81f4faf8 db_enter+0x18
cs 0x8
rflags 0x246
rsp 0xffff800020db9490
ss 0x10
db_enter+0x18: addq $0x8,%rsp
ddb{1}> show proc
PROC (softnet) pid=102222 stat=onproc
flags process=14000<NOZOMBIE,SYSTEM> proc=200<SYSTEM>
pri=32, usrpri=50, nice=20
forw=0xffffffffffffffff, list=0xffff800020d984f0,0xffff800020d98c68
process=0xffff800020d9abd0 user=0xffff800020db4000, vmspace=0xffffffff828deaf8
estcpu=0, cpticks=2, pctcpu=0.1
user=0, sys=2, intr=0
ddb{1}> ps
PID TID PPID UID S FLAGS WAIT COMMAND
30539 139308 62850 0 2 0x2 syz-executor.1
58707 422593 1 0 3 0x100083 ttyin getty
84591 192581 0 0 3 0x14200 acct acct
73856 135794 0 0 3 0x14200 bored sosplice
62850 301227 21109 0 3 0x82 thrsleep syz-fuzzer
62850 440372 21109 0 2 0x4000482 syz-fuzzer
62850 237138 21109 0 3 0x4000082 thrsleep syz-fuzzer
62850 89651 21109 0 2 0x4000482 syz-fuzzer
62850 14559 21109 0 3 0x4000082 thrsleep syz-fuzzer
62850 67083 21109 0 3 0x4000082 thrsleep syz-fuzzer
62850 57960 21109 0 3 0x4000082 thrsleep syz-fuzzer
62850 156545 21109 0 2 0x4000002 syz-fuzzer
62850 404775 21109 0 3 0x4000082 thrsleep syz-fuzzer
21109 395483 74252 0 3 0x10008a pause ksh
74252 374416 42622 0 7 0x52 sshd
42622 20041 1 0 3 0x80 select sshd
38321 507911 40125 74 3 0x100092 bpf pflogd
40125 151826 1 0 3 0x80 netio pflogd
49380 77419 98003 73 3 0x100090 kqread syslogd
98003 129920 1 0 3 0x100082 netio syslogd
85777 65969 1 77 3 0x100090 poll dhclient
45352 463009 1 0 3 0x80 poll dhclient
83347 8955 0 0 3 0x14200 bored smr
90871 289910 0 0 3 0x14200 pgzero zerothread
10562 136675 0 0 3 0x14200 aiodoned aiodoned
71153 247567 0 0 3 0x14200 syncer update
48965 479310 0 0 3 0x14200 cleaner cleaner
61739 52070 0 0 3 0x14200 reaper reaper
96199 466941 0 0 3 0x14200 pgdaemon pagedaemon
90487 286673 0 0 3 0x14200 bored crynlk
77238 393031 0 0 3 0x14200 bored crypto
69426 269485 0 0 3 0x40014200 acpi0 acpi0
347 371264 0 0 3 0x40014200 idle1
*78585 102222 0 0 7 0x14200 softnet
7967 346968 0 0 3 0x14200 bored systqmp
51961 264473 0 0 3 0x14200 bored systq
68081 272363 0 0 3 0x40014200 bored softclock
28254 143909 0 0 3 0x40014200 idle0
1 241409 0 0 3 0x82 wait init
0 0 -1 0 3 0x10200 scheduler swapper
ddb{1}> show all locks
CPU 1:
exclusive mutex /syzkaller/managers/multicore/kernel/sys/dev/kcov.c:92 r = 0 (0xffffffff82744e30)
#0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164
#1 mtx_enter_try+0x100
#2 mtx_enter+0x4b sys/kern/kern_lock.c:266
#3 kcov_remote_enter+0x62 kr_lookup sys/dev/kcov.c:676 [inline]
#3 kcov_remote_enter+0x62 sys/dev/kcov.c:513
#4 taskq_thread+0xd9 sys/kern/kern_task.c:447
#5 proc_trampoline+0x1c
Process 30539 (syz-executor.1) thread 0xffff800020eb33d8 (139308)
exclusive rrwlock inode r = 0 (0xfffffd806e5bd1a8)
#0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164
#1 rw_enter+0x446 sys/kern/kern_rwlock.c:311
#2 rrw_enter+0x88 sys/kern/kern_rwlock.c:462
#3 ufs_ihashins+0x45 sys/ufs/ufs/ufs_ihash.c:140
#4 ffs_vget+0x135 sys/ufs/ffs/ffs_vfsops.c:1350
#5 ffs_inode_alloc+0x1e1 sys/ufs/ffs/ffs_alloc.c:394
#6 ufs_mkdir+0xf4 sys/ufs/ufs/ufs_vnops.c:1162
#7 VOP_MKDIR+0xc6 sys/kern/vfs_vops.c:450
#8 domkdirat+0x121 sys/kern/vfs_syscalls.c:3051
#9 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#9 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570
#10 Xsyscall+0x128
exclusive rrwlock inode r = 0 (0xfffffd8066ca82c0)
#0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164
#1 rw_enter+0x446 sys/kern/kern_rwlock.c:311
#2 rrw_enter+0x88 sys/kern/kern_rwlock.c:462
#3 VOP_LOCK+0x4b sys/kern/vfs_vops.c:603
#4 vn_lock+0x6c sys/kern/vfs_vnops.c:575
#5 vfs_lookup+0xe6 sys/kern/vfs_lookup.c:419
#6 namei+0x5f7 sys/kern/vfs_lookup.c:249
#7 domkdirat+0x75 sys/kern/vfs_syscalls.c:3036
#8 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#8 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570
#9 Xsyscall+0x128
Process 74252 (sshd) thread 0xffff8000fffff648 (374416)
exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82896a28)
#0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164
#1 __mp_acquire_count+0x4c sys/kern/kern_lock.c:227
#2 mi_switch+0x390 sys/kern/sched_bsd.c:435
#3 sleep_finish+0x111 sys/kern/kern_synch.c:418
#4 rw_enter+0x3cf
#5 solock+0x5a sys/kern/uipc_socket2.c:282
#6 soo_poll+0x3d sys/kern/sys_socket.c:161
#7 selscan+0x14d sys/kern/sys_generic.c:722
#8 dopselect+0x8b7 sys/kern/sys_generic.c:643
#9 sys_select+0x8b sys/kern/sys_generic.c:542
#10 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#10 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570
#11 Xsyscall+0x128
Process 78585 (softnet) thread 0xffff800020d989e0 (102222)
shared rwlock softnet r = 0 (0xffff80000002c070)
#0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164
#1 taskq_thread+0xcb sys/kern/kern_task.c:445
#2 proc_trampoline+0x1c
exclusive mutex /syzkaller/managers/multicore/kernel/sys/dev/kcov.c:92 r = 0 (0xffffffff82744e30)
#0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164
#1 mtx_enter_try+0x100
#2 mtx_enter+0x4b sys/kern/kern_lock.c:266
#3 kcov_remote_enter+0x62 kr_lookup sys/dev/kcov.c:676 [inline]
#3 kcov_remote_enter+0x62 sys/dev/kcov.c:513
#4 taskq_thread+0xd9 sys/kern/kern_task.c:447
#5 proc_trampoline+0x1c
ddb{1}> show malloc
Type InUse MemUse HighUse Limit Requests Type Lim
devbuf 9547 6441K 7785K 78643K 21188 0
pcb 13 8K 8K 78643K 503 0
rtable 77 11K 12K 78643K 1346 0
ifaddr 84 16K 17K 78643K 495 0
counters 43 33K 34K 78643K 207 0
ioctlops 0 0K 4K 78643K 1911 0
iov 0 0K 24K 78643K 493 0
mount 1 1K 1K 78643K 1 0
vnodes 1232 77K 78K 78643K 4944 0
UFS quota 1 32K 32K 78643K 1 0
UFS mount 5 36K 36K 78643K 5 0
shm 2 1K 9K 78643K 52 0
VM map 2 1K 1K 78643K 2 0
sem 12 0K 1K 78643K 888 0
dirhash 12 2K 2K 78643K 12 0
ACPI 1824 197K 290K 78643K 13058 0
file desc 4 9K 25K 78643K 9034 0
sigio 0 0K 0K 78643K 34 0
proc 65 63K 95K 78643K 1069 0
subproc 32 2K 2K 78643K 119 0
NFS srvsock 1 0K 0K 78643K 1 0
NFS daemon 1 16K 16K 78643K 1 0
ip_moptions 0 0K 0K 78643K 630 0
in_multi 22 1K 2K 78643K 412 0
ether_multi 1 0K 0K 78643K 71 0
mrt 0 0K 0K 78643K 69 0
ISOFS mount 1 32K 32K 78643K 1 0
MSDOSFS mount 1 16K 16K 78643K 1 0
ttys 73 334K 334K 78643K 73 0
exec 0 0K 2K 78643K 829 0
pfkey data 0 0K 1K 78643K 5 0
pagedep 1 8K 8K 78643K 1 0
inodedep 1 32K 32K 78643K 1 0
newblk 1 0K 0K 78643K 1 0
VM swap 7 26K 26K 78643K 7 0
UVM amap 250 291K 291K 78643K 21796 0
UVM aobj 69 5K 5K 78643K 82 0
memdesc 1 4K 4K 78643K 1 0
crypto data 1 1K 1K 78643K 1 0
ip6_options 0 0K 0K 78643K 400 0
NDP 16 0K 0K 78643K 124 0
temp 149 3967K 4039K 78643K 50139 0
kqueue 3 4K 18K 78643K 381 0
SYN cache 2 16K 16K 78643K 2 0
ddb{1}> show all pools
Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
arp 64 22 0 18 1 0 1 1 0 8 0
plcache 128 20 0 0 1 0 1 1 0 8 0
rtpcb 96 313 0 311 1 0 1 1 0 8 0
rtentry 112 153 0 128 2 0 2 2 0 8 0
unpcb 120 2059 0 2003 3 1 2 3 0 8 0
syncache 272 78 0 78 10 10 0 1 0 8 0
tcpqe 32 27 0 27 4 4 0 1 0 8 0
tcpcb 592 1571 0 1567 21 19 2 5 0 8 1
inpcb 296 4484 0 4477 12 10 2 3 0 8 1
rttmr 72 33 0 33 4 3 1 1 0 8 1
nd6 48 32 0 29 1 0 1 1 0 8 0
pkpcb 40 37 0 37 5 5 0 1 0 8 0
kcovpl 48 7 0 5 1 0 1 1 0 8 0
ppxss 1136 43 0 43 6 5 1 1 0 8 1
pffrag 232 27 0 27 3 3 0 1 0 482 0
pffrnode 88 27 0 27 3 3 0 1 0 8 0
pffrent 40 612 0 612 3 3 0 1 0 8 0
pfosfp 40 847 0 423 5 0 5 5 0 8 0
pfosfpen 112 1429 0 714 21 0 21 21 0 8 0
pfrktable 1344 42 0 42 3 3 0 1 0 8 0
pftag 88 1 0 0 1 0 1 1 0 8 0
pfqueue 264 8 0 8 1 1 0 1 0 8 0
pfstitem 24 49 0 47 1 0 1 1 0 8 0
pfstkey 112 49 0 47 2 1 1 2 0 8 0
pfstate 328 49 0 47 4 3 1 4 0 8 0
pfrule 1360 65 0 64 2 1 1 2 0 8 0
art_heap8 4096 1 0 0 1 0 1 1 0 8 0
art_heap4 256 419 0 282 12 3 9 12 0 8 0
art_table 32 420 0 282 2 0 2 2 0 8 0
art_node 16 152 0 132 1 0 1 1 0 8 0
sysvmsgpl 40 44 0 21 2 1 1 1 0 8 0
semapl 112 886 0 876 1 0 1 1 0 8 0
shmpl 112 79 0 13 2 0 2 2 0 8 0
dirhash 1024 17 0 0 3 0 3 3 0 8 0
dino2pl 256 13556 0 12136 92 2 90 90 0 8 0
ffsino 272 13556 0 12136 96 0 96 96 0 8 0
nchpl 144 24684 0 23093 60 0 60 60 0 8 0
uvmvnodes 72 5926 0 0 108 0 108 108 0 8 0
vnodes 208 5926 0 0 312 0 312 312 0 8 0
namei 1024 61893 0 61892 4 3 1 1 0 8 0
percpumem 16 114 0 82 1 0 1 1 0 8 0
vcpupl 1984 19 0 0 3 0 3 3 0 8 0
vmpool 560 19 0 0 2 0 2 2 0 8 0
pfiaddrpl 120 14 0 14 3 3 0 1 0 8 0
scsiplug 72 9 0 9 2 1 1 1 0 8 1
scxspl 200 73056 0 73056 18 17 1 7 0 8 1
plimitpl 152 409 0 401 1 0 1 1 0 8 0
sigapl 424 9238 0 9206 4 0 4 4 0 8 0
futexpl 56 69241 0 69241 4 3 1 1 0 8 1
knotepl 112 546 0 526 1 0 1 1 0 8 0
kqueuepl 152 4219 0 4216 1 0 1 1 0 8 0
pipepl 304 538 0 527 16 14 2 2 0 8 1
fdescpl 496 9221 0 9206 3 0 3 3 0 8 0
filepl 152 33144 0 33042 7 2 5 6 0 8 1
lockfpl 104 1002 0 1001 1 0 1 1 0 8 0
lockfspl 48 411 0 410 1 0 1 1 0 8 0
sessionpl 120 24 0 13 1 0 1 1 0 8 0
pgrppl 48 42 0 31 1 0 1 1 0 8 0
ucredpl 96 4695 0 4683 1 0 1 1 0 8 0
zombiepl 144 9207 0 9206 2 1 1 1 0 8 0
processpl 1008 9238 0 9206 5 0 5 5 0 8 0
procpl 632 20502 0 20462 13 8 5 5 0 8 1
srpgc 72 2 0 2 1 1 0 1 0 8 0
sosppl 144 117 0 117 8 7 1 1 0 8 1
sockpl 400 6908 0 6839 14 6 8 10 0 8 0
mcl64k 65536 20 0 0 3 0 3 3 0 8 0
mcl16k 16384 10 0 0 2 0 2 2 0 8 0
mcl12k 12288 25 0 0 2 0 2 2 0 8 0
mcl9k 9216 16 0 0 2 0 2 2 0 8 0
mcl8k 8192 20 0 0 3 1 2 3 0 8 0
mcl4k 4096 26 0 0 4 1 3 3 0 8 0
mcl2k2 2112 7 0 0 1 0 1 1 0 8 0
mcl2k 2048 273 0 0 15 0 15 15 0 8 0
mtagpl 96 386 0 0 8 0 8 8 0 8 0
mbufpl 256 981 0 0 58 0 58 58 0 8 0
bufpl 280 17551 0 11295 447 0 447 447 0 8 0
anonpl 16 713507 0 705408 99 64 35 54 0 124 1
amapchunkpl 152 38964 0 38786 46 38 8 19 0 158 0
amappl16 192 31426 0 31096 67 49 18 34 0 8 1
amappl15 184 3 0 1 1 0 1 1 0 8 0
amappl14 176 3754 0 3749 1 0 1 1 0 8 0
amappl13 168 103 0 101 1 0 1 1 0 8 0
amappl12 160 278 0 273 1 0 1 1 0 8 0
amappl11 152 67 0 52 1 0 1 1 0 8 0
amappl10 144 4958 0 4953 1 0 1 1 0 8 0
amappl9 136 317 0 317 1 1 0 1 0 8 0
amappl8 128 410 0 278 5 0 5 5 0 8 0
amappl7 120 5255 0 5246 1 0 1 1 0 8 0
amappl6 112 155 0 133 1 0 1 1 0 8 0
amappl5 104 9442 0 9428 1 0 1 1 0 8 0
amappl4 96 395 0 364 1 0 1 1 0 8 0
amappl3 88 4007 0 3999 1 0 1 1 0 8 0
amappl2 80 64618 0 64542 3 1 2 3 0 8 0
amappl1 72 243217 0 242782 25 15 10 19 0 8 0
amappl 80 20907 0 20836 2 0 2 2 0 84 0
dma4096 4096 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 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 64 81 0 13 2 0 2 2 0 8 0
uaddrrnd 24 9240 0 9206 1 0 1 1 0 8 0
uaddrbest 32 2 0 0 1 0 1 1 0 8 0
uaddr 24 9240 0 9206 1 0 1 1 0 8 0
vmmpekpl 168 39945 0 39898 3 0 3 3 0 8 0
vmmpepl 168 1118602 0 1117045 149 69 80 90 0 357 2
vmsppl 368 9239 0 9206 5 1 4 4 0 8 0
pdppl 4096 18487 0 18431 10 2 8 8 0 8 0
pvpl 32 3023594 0 3012586 285 171 114 151 0 265 21
pmappl 232 9239 0 9206 4 1 3 3 0 8 0
extentpl 40 53 0 36 1 0 1 1 0 8 0
phpool 112 336 0 32 9 0 9 9 0 8 0
ddb{1}> machine ddbcpu 0
Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp
x86_ipi_db(ffffffff826d7ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:352
x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23
__sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc
pipe_poll(fffffd806fc0d720,1,ffff8000fffff648) at pipe_poll+0x17c sys/kern/sys_pipe.c:738
selscan(ffff8000fffff648,ffff800020e14810,ffff800020e1481c,c,4,ffff800020e149f0) at selscan+0x14d sys/kern/sys_generic.c:722
dopselect(ffff8000fffff648,c,4317bb3ef20,432490e29e0,0,0) at dopselect+0x8b7 sys/kern/sys_generic.c:643
sys_select(ffff8000fffff648,ffff800020e149a0,ffff800020e149f0) at sys_select+0x8b sys/kern/sys_generic.c:542
syscall(ffff800020e14a70) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800020e14a70) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffd4ab0, count: 5
ddb{0}> trace
x86_ipi_db(ffffffff826d7ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:352
x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23
__sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc
pipe_poll(fffffd806fc0d720,1,ffff8000fffff648) at pipe_poll+0x17c sys/kern/sys_pipe.c:738
selscan(ffff8000fffff648,ffff800020e14810,ffff800020e1481c,c,4,ffff800020e149f0) at selscan+0x14d sys/kern/sys_generic.c:722
dopselect(ffff8000fffff648,c,4317bb3ef20,432490e29e0,0,0) at dopselect+0x8b7 sys/kern/sys_generic.c:643
sys_select(ffff8000fffff648,ffff800020e149a0,ffff800020e149f0) at sys_select+0x8b sys/kern/sys_generic.c:542
syscall(ffff800020e14a70) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800020e14a70) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffd4ab0, count: -10
ddb{0}> machine ddbcpu 1
Stopped at db_enter+0x18: addq $0x8,%rsp
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff823bf498) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242d3f9,ffffffff8242c702,207,ffffffff823d1f6e) at __assert+0x2b sys/kern/subr_prf.c:162
kcov_remote_enter(0,ffff800020eb4bd8) at kcov_remote_enter+0x155 sys/dev/kcov.c:519
taskq_thread(ffff80000002c000) at taskq_thread+0xd9 sys/kern/kern_task.c:447
end trace frame: 0x0, count: 10
ddb{1}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff823bf498) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242d3f9,ffffffff8242c702,207,ffffffff823d1f6e) at __assert+0x2b sys/kern/subr_prf.c:162
kcov_remote_enter(0,ffff800020eb4bd8) at kcov_remote_enter+0x155 sys/dev/kcov.c:519
taskq_thread(ffff80000002c000) at taskq_thread+0xd9 sys/kern/kern_task.c:447
end trace frame: 0x0, count: -5