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
514551 26976 73 0x100010 0 0 syslogd
*360189 14771 0 0x14000 0x200 1 softnet
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff823c07fb) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242e1df,ffffffff82429222,207,ffffffff823ce86e) at __assert+0x2b sys/kern/subr_prf.c:162
kcov_remote_enter(0,ffff800020ec4bd8) 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(ffffffff823c07fb) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242e1df,ffffffff82429222,207,ffffffff823ce86e) at __assert+0x2b sys/kern/subr_prf.c:162
kcov_remote_enter(0,ffff800020ec4bd8) 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 0xffff800020db9cb0
rbx 0xffff800020db9cc0
rdx 0x8b
rcx 0x2
rax 0x1
r8 0xffff800020db9c70
r9 0xffffffff814cffb6 kprintf+0x146
r10 0x1
r11 0x559822f4eb52c7ca
r12 0x3000000008
r13 0xffff800020db9d60
r14 0x100
r15 0x1
rip 0xffffffff8178dc98 db_enter+0x18
cs 0x8
rflags 0x246
rsp 0xffff800020db9ca0
ss 0x10
db_enter+0x18: addq $0x8,%rsp
ddb{1}> show proc
PROC (softnet) pid=360189 stat=onproc
flags process=14000<NOZOMBIE,SYSTEM> proc=200<SYSTEM>
pri=32, usrpri=50, nice=20
forw=0xffffffffffffffff, list=0xffff800020d98768,0xffff800020d98288
process=0xffff800020d9b3b0 user=0xffff800020db4000, vmspace=0xffffffff828e8b68
estcpu=0, cpticks=1, pctcpu=0.0
user=0, sys=1, intr=0
ddb{1}> ps
PID TID PPID UID S FLAGS WAIT COMMAND
20722 106720 96130 0 2 0x2 syz-executor.1
77166 433287 0 0 3 0x14280 nfsidl nfsio
61957 232054 0 0 3 0x14280 nfsidl nfsio
38926 285097 0 0 3 0x14280 nfsidl nfsio
46142 373687 0 0 3 0x14280 nfsidl nfsio
84256 337494 0 0 3 0x14280 nfsidl nfsio
28180 226022 0 0 3 0x14280 nfsidl nfsio
43021 446620 0 0 3 0x14280 nfsidl nfsio
71266 356600 0 0 3 0x14280 nfsidl nfsio
88536 312922 0 0 3 0x14280 nfsidl nfsio
69147 468983 0 0 3 0x14280 nfsidl nfsio
45849 134833 0 0 3 0x14280 nfsidl nfsio
20110 25307 0 0 3 0x14280 nfsidl nfsio
15646 439697 0 0 3 0x14280 nfsidl nfsio
61141 86801 0 0 3 0x14280 nfsidl nfsio
20645 447391 0 0 3 0x14280 nfsidl nfsio
73967 508003 0 0 3 0x14280 nfsidl nfsio
25132 106867 0 0 3 0x14280 nfsidl nfsio
79613 502711 0 0 3 0x14280 nfsidl nfsio
44825 460124 0 0 3 0x14280 nfsidl nfsio
89436 208533 0 0 3 0x14280 nfsidl nfsio
4824 154991 0 0 3 0x14200 bored sosplice
20043 473591 1 0 3 0x100083 ttyin getty
96130 251360 61995 0 3 0x82 thrsleep syz-fuzzer
96130 177356 61995 0 3 0x4000082 nanosleep syz-fuzzer
96130 447200 61995 0 3 0x4000082 kqread syz-fuzzer
96130 237087 61995 0 3 0x4000082 thrsleep syz-fuzzer
96130 384298 61995 0 3 0x4000082 thrsleep syz-fuzzer
96130 23804 61995 0 3 0x4000082 thrsleep syz-fuzzer
96130 84471 61995 0 3 0x4000082 thrsleep syz-fuzzer
96130 53429 61995 0 3 0x4000082 thrsleep syz-fuzzer
61995 5676 47685 0 3 0x10008a pause ksh
47685 280143 97833 0 3 0x92 select sshd
97833 335522 1 0 3 0x80 select sshd
75786 324328 83004 74 3 0x100092 bpf pflogd
83004 370348 1 0 3 0x80 netio pflogd
26976 514551 46013 73 7 0x100010 syslogd
46013 420494 1 0 3 0x100082 netio syslogd
43105 410884 1 77 3 0x100090 poll dhclient
9052 147898 1 0 3 0x80 poll dhclient
29246 413235 0 0 3 0x14200 bored smr
43502 139933 0 0 2 0x14200 zerothread
6472 438134 0 0 3 0x14200 aiodoned aiodoned
87342 127538 0 0 3 0x14200 syncer update
70549 258079 0 0 3 0x14200 cleaner cleaner
32058 454414 0 0 3 0x14200 reaper reaper
93204 504179 0 0 3 0x14200 pgdaemon pagedaemon
30845 197525 0 0 3 0x14200 bored crynlk
85256 10198 0 0 3 0x14200 bored crypto
2257 260560 0 0 3 0x40014200 acpi0 acpi0
4863 439018 0 0 3 0x40014200 idle1
*14771 360189 0 0 7 0x14200 softnet
39657 512404 0 0 3 0x14200 bored systqmp
10429 229370 0 0 3 0x14200 bored systq
73579 158546 0 0 3 0x40014200 bored softclock
60635 512540 0 0 3 0x40014200 idle0
1 70692 0 0 3 0x82 wait init
0 0 -1 0 3 0x10200 scheduler swapper
ddb{1}> show all locks
CPU 0:
exclusive mutex &map->mtx r = 0 (0xffffffff827cb378)
#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 vm_map_lock_ln+0x118 sys/uvm/uvm_map.c:5454
#4 uvm_map+0x325 sys/uvm/uvm_map.c:1236
#5 uvm_km_kmemalloc_pla+0x11d sys/uvm/uvm_km.c:335
#6 malloc+0x43e sys/kern/kern_malloc.c:230
#7 ufs_readdir+0x148 sys/ufs/ufs/ufs_vnops.c:1456
#8 VOP_READDIR+0xc6 sys/kern/vfs_vops.c:520
#9 sys_getdents+0x21d sys/kern/vfs_syscalls.c:3121
#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
CPU 1:
exclusive mutex /syzkaller/managers/multicore/kernel/sys/dev/kcov.c:92 r = 0 (0xffffffff826ce048)
#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 20722 (syz-executor.1) thread 0xffff800020e4c2b0 (106720)
Process 26976 (syslogd) thread 0xffff8000fffff3d0 (514551)
Process 14771 (softnet) thread 0xffff800020d984f0 (360189)
ddb{1}> show malloc
Type InUse MemUse HighUse Limit Requests Type Lim
devbuf 9538 6441K 7206K 78643K 17690 0
pcb 13 8K 8K 78643K 418 0
rtable 85 3K 7K 78643K 1616 0
ifaddr 83 16K 16K 78643K 547 0
counters 45 34K 34K 78643K 173 0
ioctlops 0 0K 4K 78643K 2107 0
iov 0 0K 24K 78643K 392 0
mount 1 1K 1K 78643K 1 0
vnodes 1227 77K 77K 78643K 3749 0
UFS quota 1 32K 32K 78643K 1 0
UFS mount 5 36K 36K 78643K 5 0
shm 2 1K 9K 78643K 108 0
VM map 2 1K 1K 78643K 2 0
sem 12 1K 1K 78643K 90 0
dirhash 12 2K 2K 78643K 12 0
ACPI 1824 197K 290K 78643K 13058 0
file desc 4 9K 25K 78643K 7275 0
sigio 0 0K 0K 78643K 119 0
proc 64 63K 95K 78643K 1189 0
subproc 32 2K 2K 78643K 102 0
NFS srvsock 1 0K 0K 78643K 1 0
NFS daemon 1 16K 16K 78643K 1 0
ip_moptions 0 0K 0K 78643K 453 0
in_multi 26 1K 2K 78643K 380 0
ether_multi 1 0K 0K 78643K 84 0
mrt 0 0K 0K 78643K 86 0
ISOFS mount 1 32K 32K 78643K 1 0
MSDOSFS mount 1 16K 16K 78643K 1 0
ttys 61 281K 281K 78643K 61 0
exec 0 0K 2K 78643K 758 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 446 1264K 1272K 78643K 17941 0
UVM aobj 131 8K 8K 78643K 131 0
memdesc 1 4K 4K 78643K 1 0
crypto data 1 1K 1K 78643K 1 0
ip6_options 0 0K 0K 78643K 272 0
NDP 15 0K 0K 78643K 121 0
temp 145 3963K 4092K 78643K 44964 0
kqueue 3 4K 22K 78643K 380 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 19 0 13 1 0 1 1 0 8 0
plcache 128 20 0 0 1 0 1 1 0 8 0
rtpcb 96 296 0 294 1 0 1 1 0 8 0
rtentry 112 196 0 165 2 0 2 2 0 8 0
unpcb 120 2103 0 2087 1 0 1 1 0 8 0
syncache 272 51 0 51 7 7 0 1 0 8 0
tcpqe 32 17 0 17 5 5 0 1 0 8 0
tcpcb 592 1425 0 1413 23 21 2 5 0 8 0
ipq 40 4 0 4 1 1 0 1 0 8 0
ipqe 40 12 0 12 1 1 0 1 0 8 0
inpcb 296 3610 0 3601 7 5 2 2 0 8 0
rttmr 72 25 0 25 3 3 0 1 0 8 0
nd6 48 55 0 51 1 0 1 1 0 8 0
pkpcb 40 36 0 36 5 5 0 1 0 8 0
kcovpl 48 6 0 4 1 0 1 1 0 8 0
ppxss 1136 14 0 14 2 1 1 1 0 8 1
pfstscr 40 26 0 26 2 2 0 1 0 8 0
pffrag 232 19 0 19 4 3 1 1 0 482 1
pffrnode 88 19 0 19 4 3 1 1 0 8 1
pffrent 40 51 0 51 6 5 1 1 0 8 1
pfosfp 40 847 0 423 5 0 5 5 0 8 0
pfosfpen 112 1436 0 714 21 0 21 21 0 8 0
pfrktable 1344 214 0 214 3 3 0 1 0 8 0
pftag 88 3 0 1 1 0 1 1 0 8 0
pfqueue 264 10 0 5 1 0 1 1 0 8 0
pfstitem 24 89 0 87 1 0 1 1 0 8 0
pfstkey 112 131 0 129 2 1 1 2 0 8 0
pfstate 328 110 0 108 7 6 1 5 0 8 0
pfrule 1360 82 0 76 2 1 1 2 0 8 0
art_heap8 4096 1 0 0 1 0 1 1 0 8 0
art_heap4 256 781 0 644 17 5 12 17 0 8 1
art_table 32 782 0 644 3 1 2 3 0 8 0
art_node 16 192 0 166 1 0 1 1 0 8 0
sysvmsgpl 40 40 0 0 1 0 1 1 0 8 0
semupl 112 6 0 6 1 1 0 1 0 8 0
semapl 112 81 0 71 1 0 1 1 0 8 0
shmpl 112 128 0 0 4 0 4 4 0 8 0
dirhash 1024 17 0 0 3 0 3 3 0 8 0
dino2pl 256 10881 0 9472 92 3 89 89 0 8 0
ffsino 272 10881 0 9472 95 0 95 95 0 8 0
nchpl 144 19787 0 18194 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 50220 0 50220 2 1 1 1 0 8 1
percpumem 16 97 0 64 1 0 1 1 0 8 0
vcpupl 1984 78 0 0 10 0 10 10 0 8 0
vmpool 560 95 0 17 6 0 6 6 0 8 0
pfiaddrpl 120 59 0 59 2 2 0 1 0 8 0
scsiplug 72 7 0 7 1 1 0 1 0 8 0
scxspl 200 60470 0 60470 14 13 1 7 0 8 1
plimitpl 152 391 0 383 1 0 1 1 0 8 0
sigapl 424 7500 0 7449 6 0 6 6 0 8 0
futexpl 56 56490 0 56490 3 2 1 1 0 8 1
knotepl 112 650 0 630 2 1 1 2 0 8 0
kqueuepl 152 3243 0 3241 1 0 1 1 0 8 0
pipepl 304 535 0 524 13 11 2 2 0 8 0
fdescpl 496 7464 0 7449 3 0 3 3 0 8 0
filepl 152 27641 0 27538 8 3 5 6 0 8 0
lockfpl 104 899 0 898 1 0 1 1 0 8 0
lockfspl 48 323 0 322 1 0 1 1 0 8 0
sessionpl 120 23 0 12 1 0 1 1 0 8 0
pgrppl 48 59 0 48 1 0 1 1 0 8 0
ucredpl 96 4091 0 4082 1 0 1 1 0 8 0
zombiepl 144 7450 0 7449 2 1 1 1 0 8 0
processpl 1008 7500 0 7449 7 0 7 7 0 8 0
procpl 632 16647 0 16589 8 2 6 6 0 8 0
sosppl 144 97 0 97 7 6 1 1 0 8 1
sockpl 400 6051 0 6024 15 11 4 5 0 8 1
mcl64k 65536 21 0 0 3 0 3 3 0 8 0
mcl16k 16384 4 0 0 1 0 1 1 0 8 0
mcl12k 12288 17 0 0 2 0 2 2 0 8 0
mcl9k 9216 11 0 0 1 0 1 1 0 8 0
mcl8k 8192 25 0 0 4 1 3 3 0 8 0
mcl4k 4096 25 0 0 3 0 3 3 0 8 0
mcl2k2 2112 5 0 0 1 0 1 1 0 8 0
mcl2k 2048 314 0 0 16 0 16 16 0 8 0
mtagpl 96 477 0 0 12 0 12 12 0 8 0
mbufpl 256 1339 0 0 74 0 74 74 0 8 0
bufpl 280 15408 0 9150 448 0 448 448 0 8 0
anonpl 16 569346 0 561794 86 41 45 55 0 124 14
amapchunkpl 152 29989 0 29788 26 13 13 21 0 158 4
amappl16 192 25932 0 25605 63 40 23 35 0 8 6
amappl15 184 142 0 140 1 0 1 1 0 8 0
amappl14 176 923 0 913 1 0 1 1 0 8 0
amappl13 168 117 0 114 1 0 1 1 0 8 0
amappl12 160 5121 0 5114 1 0 1 1 0 8 0
amappl11 152 68 0 53 1 0 1 1 0 8 0
amappl10 144 331 0 325 1 0 1 1 0 8 0
amappl9 136 282 0 282 1 1 0 1 0 8 0
amappl8 128 410 0 293 4 0 4 4 0 8 0
amappl7 120 616 0 608 1 0 1 1 0 8 0
amappl6 112 166 0 141 1 0 1 1 0 8 0
amappl5 104 6875 0 6861 1 0 1 1 0 8 0
amappl4 96 1264 0 1225 1 0 1 1 0 8 0
amappl3 88 1124 0 1117 1 0 1 1 0 8 0
amappl2 80 57255 0 57171 4 1 3 3 0 8 0
amappl1 72 200456 0 200013 24 14 10 19 0 8 0
amappl 80 17106 0 16945 4 0 4 4 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 64 130 0 0 3 0 3 3 0 8 0
uaddrrnd 24 7559 0 7466 1 0 1 1 0 8 0
uaddrbest 32 2 0 0 1 0 1 1 0 8 0
uaddr 24 7559 0 7466 1 0 1 1 0 8 0
vmmpekpl 168 41176 0 41121 3 0 3 3 0 8 0
vmmpepl 168 913211 0 911455 142 48 94 100 0 357 7
vmsppl 368 7558 0 7466 9 0 9 9 0 8 0
pdppl 4096 15125 0 15010 16 0 16 16 0 8 1
pvpl 32 2441252 0 2430494 269 147 122 141 0 265 32
pmappl 232 7558 0 7466 6 0 6 6 0 8 0
extentpl 40 53 0 36 1 0 1 1 0 8 0
phpool 112 362 0 31 10 0 10 10 0 8 0
ddb{1}> machine ddbcpu 0
Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp
x86_ipi_db(ffffffff8274fff0) 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+0x6f sys/dev/kcov.c:118
__mp_acquire_count(ffffffff8287d640,1) at __mp_acquire_count+0x4c sys/kern/kern_lock.c:227
mi_switch() at mi_switch+0x390 sys/kern/sched_bsd.c:435
sleep_finish(ffff800020e62b80,1) at sleep_finish+0x111 sys/kern/kern_synch.c:418
sleep_finish_all(ffff800020e62b80,1) at sleep_finish_all+0x32 sleep_finish_timeout sys/kern/kern_synch.c:447 [inline]
sleep_finish_all(ffff800020e62b80,1) at sleep_finish_all+0x32 sys/kern/kern_synch.c:393
tsleep(fffffd806edd54a8,11,ffffffff823d28fa,0) at tsleep+0x1c2 sys/kern/kern_synch.c:155
vwaitforio(fffffd806edd5428,0,ffffffff823d28fa,ffffffffffffffff) at vwaitforio+0x98 sys/kern/vfs_subr.c:1878
ffs_fsync(ffff800020e62ce0) at ffs_fsync+0x39d sys/ufs/ffs/ffs_vnops.c:498
VOP_FSYNC(fffffd806edd5428,fffffd807f7bfae0,1,ffff8000fffff3d0) at VOP_FSYNC+0xbf sys/kern/vfs_vops.c:353
sys_fsync(ffff8000fffff3d0,ffff800020e62dd0,ffff800020e62e20) at sys_fsync+0x127 sys/kern/vfs_syscalls.c:2874
syscall(ffff800020e62ea0) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800020e62ea0) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570
end trace frame: 0xffff800020e62f20, count: 0
ddb{0}> trace
x86_ipi_db(ffffffff8274fff0) 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+0x6f sys/dev/kcov.c:118
__mp_acquire_count(ffffffff8287d640,1) at __mp_acquire_count+0x4c sys/kern/kern_lock.c:227
mi_switch() at mi_switch+0x390 sys/kern/sched_bsd.c:435
sleep_finish(ffff800020e62b80,1) at sleep_finish+0x111 sys/kern/kern_synch.c:418
sleep_finish_all(ffff800020e62b80,1) at sleep_finish_all+0x32 sleep_finish_timeout sys/kern/kern_synch.c:447 [inline]
sleep_finish_all(ffff800020e62b80,1) at sleep_finish_all+0x32 sys/kern/kern_synch.c:393
tsleep(fffffd806edd54a8,11,ffffffff823d28fa,0) at tsleep+0x1c2 sys/kern/kern_synch.c:155
vwaitforio(fffffd806edd5428,0,ffffffff823d28fa,ffffffffffffffff) at vwaitforio+0x98 sys/kern/vfs_subr.c:1878
ffs_fsync(ffff800020e62ce0) at ffs_fsync+0x39d sys/ufs/ffs/ffs_vnops.c:498
VOP_FSYNC(fffffd806edd5428,fffffd807f7bfae0,1,ffff8000fffff3d0) at VOP_FSYNC+0xbf sys/kern/vfs_vops.c:353
sys_fsync(ffff8000fffff3d0,ffff800020e62dd0,ffff800020e62e20) at sys_fsync+0x127 sys/kern/vfs_syscalls.c:2874
syscall(ffff800020e62ea0) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800020e62ea0) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffe3120, count: -15
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(ffffffff823c07fb) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242e1df,ffffffff82429222,207,ffffffff823ce86e) at __assert+0x2b sys/kern/subr_prf.c:162
kcov_remote_enter(0,ffff800020ec4bd8) 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(ffffffff823c07fb) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242e1df,ffffffff82429222,207,ffffffff823ce86e) at __assert+0x2b sys/kern/subr_prf.c:162
kcov_remote_enter(0,ffff800020ec4bd8) 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