assert "ifp != NULL" failed in if_ether.c (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ba2d51441d9e zap stray space (CRITICAL!)
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=1620b7b9880000
kernel config: https://syzkaller.appspot.com/x/.config?x=7058272de1526588
dashboard link: https://syzkaller.appspot.com/bug?extid=4db5af006a69aff02844

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/442cf03bffb0/disk-ba2d5144.raw.xz
bsd.gdb: https://storage.googleapis.com/syzbot-assets/6d8b1ed374d1/bsd-ba2d5144.gdb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/24669aa7dfa4/kernel-ba2d5144.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4db5af...@syzkaller.appspotmail.com

panic: kernel diagnostic assertion "ifp != NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/netinet/if_ether.c", line 776
Stopped at db_enter+0x18: addq $0x8,%rsp
TID PID UID PRFLAGS PFLAGS CPU COMMAND
176980 68533 0 0x2 0 1 syz-executor.4
*120987 59418 0 0x14000 0x40000200 0K softclock
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437
panic(ffffffff825af7a0) at panic+0x177 sys/kern/subr_prf.c:198
__assert(ffffffff82622d21,ffffffff8261f053,308,ffffffff8257c3e4) at __assert+0x25 sys/kern/subr_prf.c:157
arptfree(fffffd806843a5c0) at arptfree+0x12e sys/netinet/if_ether.c:776
arptimer(ffffffff82a36328) at arptimer+0x88 sys/netinet/if_ether.c:135
timeout_run(ffffffff82a36328) at timeout_run+0xcc sys/kern/kern_timeout.c:653
softclock_thread(ffff8000211e97a0) at softclock_thread+0x134 sys/kern/kern_timeout.c:777
end trace frame: 0x0, count: 8
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 "ifp != NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/netinet/if_ether.c", line 776
ddb{0}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437
panic(ffffffff825af7a0) at panic+0x177 sys/kern/subr_prf.c:198
__assert(ffffffff82622d21,ffffffff8261f053,308,ffffffff8257c3e4) at __assert+0x25 sys/kern/subr_prf.c:157
arptfree(fffffd806843a5c0) at arptfree+0x12e sys/netinet/if_ether.c:776
arptimer(ffffffff82a36328) at arptimer+0x88 sys/netinet/if_ether.c:135
timeout_run(ffffffff82a36328) at timeout_run+0xcc sys/kern/kern_timeout.c:653
softclock_thread(ffff8000211e97a0) at softclock_thread+0x134 sys/kern/kern_timeout.c:777
end trace frame: 0x0, count: -7
ddb{0}> show registers
rdi 0
rsi 0x1
rbp 0xffff8000211f5180
rbx 0xffffffff82999b8f cpu_info_full_primary+0x2b8f
rdx 0
rcx 0
rax 0xffff8000211e97a0
r8 0x101010101010101
r9 0x8080808080808080
r10 0x7ce065f121511b83
r11 0x181eba5226a94b0d
r12 0xffffffff82999990 cpu_info_full_primary+0x2990
r13 0
r14 0
r15 0x1
rip 0xffffffff81aec918 db_enter+0x18
cs 0x8
rflags 0x246
rsp 0xffff8000211f5170
ss 0
db_enter+0x18: addq $0x8,%rsp
ddb{0}> show proc
PROC (softclock) pid=120987 stat=onproc
flags process=14000<NOZOMBIE,SYSTEM> proc=40000200<SYSTEM,CPUPEG>
pri=0, usrpri=50, nice=20
forw=0xffffffffffffffff, list=0xffff8000211e9a40,0xffff8000211e9510
process=0xffff8000ffffe990 user=0xffff8000211f0000, vmspace=0xffffffff82a553a8
estcpu=0, cpticks=1, pctcpu=0.1
user=0, sys=1, intr=0
ddb{0}> ps
PID TID PPID UID S FLAGS WAIT COMMAND
73669 54012 29056 0 2 0 syz-executor.6
73669 349178 29056 0 3 0x4000080 fsleep syz-executor.6
73669 438495 29056 0 3 0x4000080 fsleep syz-executor.6
17072 429983 93143 0 2 0x4081000 syz-executor.1
17072 263880 93143 0 2 0x4081000 syz-executor.1
17072 284922 93143 0 2 0x4081000 syz-executor.1
17072 510532 93143 0 3 0x4003000 suspend syz-executor.1
27808 47545 68338 0 2 0 syz-executor.7
27808 14189 68338 0 2 0x4000000 syz-executor.7
16526 323706 67144 0 2 0 syz-executor.2
16526 121106 67144 0 3 0x4000080 lockf syz-executor.2
16526 502551 67144 0 2 0x4000000 syz-executor.2
16526 87594 67144 0 2 0x4000000 syz-executor.2
16526 257808 67144 0 2 0x4000000 syz-executor.2
53043 358322 68533 0 2 0 syz-executor.4
53043 45278 68533 0 3 0x4000080 netio syz-executor.4
43516 16467 0 0 3 0x14280 nfsidl nfsio
81018 305289 0 0 3 0x14280 nfsidl nfsio
72902 231921 0 0 3 0x14280 nfsidl nfsio
53477 24233 0 0 3 0x14280 nfsidl nfsio
72533 440481 0 0 3 0x14280 nfsidl nfsio
19087 14392 0 0 3 0x14280 nfsidl nfsio
88645 8863 0 0 3 0x14280 nfsidl nfsio
25545 7299 0 0 3 0x14280 nfsidl nfsio
29589 283179 0 0 3 0x14280 nfsidl nfsio
11056 21839 0 0 3 0x14280 nfsidl nfsio
23265 102312 0 0 3 0x14280 nfsidl nfsio
93323 444162 0 0 3 0x14280 nfsidl nfsio
65097 365154 0 0 3 0x14280 nfsidl nfsio
44450 391409 0 0 3 0x14280 nfsidl nfsio
97581 419391 0 0 3 0x14280 nfsidl nfsio
75625 83829 0 0 3 0x14280 nfsidl nfsio
2026 106537 0 0 3 0x14280 nfsidl nfsio
75249 347474 0 0 3 0x14280 nfsidl nfsio
10892 302420 0 0 3 0x14280 nfsidl nfsio
19090 264947 0 0 3 0x14280 nfsidl nfsio
29056 409067 38030 0 3 0x82 nanoslp syz-executor.6
68338 462131 38030 0 2 0x482 syz-executor.7
67144 322346 38030 0 2 0x482 syz-executor.2
14353 56017 38030 0 2 0x482 syz-executor.3
93143 479621 38030 0 2 0x482 syz-executor.1
68533 176980 38030 0 7 0x2 syz-executor.4
23840 27945 38030 0 2 0x2 syz-executor.5
48561 218089 0 0 3 0x14200 bored sosplice
38030 106456 33615 0 3 0x82 thrsleep syz-fuzzer
38030 173601 33615 0 3 0x4000082 thrsleep syz-fuzzer
38030 296935 33615 0 3 0x4000082 thrsleep syz-fuzzer
38030 23723 33615 0 3 0x4000082 thrsleep syz-fuzzer
38030 142877 33615 0 3 0x4000082 wait syz-fuzzer
38030 47138 33615 0 3 0x4000082 wait syz-fuzzer
38030 262266 33615 0 3 0x4000082 thrsleep syz-fuzzer
38030 89837 33615 0 3 0x4000082 thrsleep syz-fuzzer
38030 46266 33615 0 3 0x4000082 thrsleep syz-fuzzer
38030 322247 33615 0 3 0x4000082 wait syz-fuzzer
38030 357467 33615 0 3 0x4000082 wait syz-fuzzer
38030 129735 33615 0 3 0x4000082 wait syz-fuzzer
38030 481967 33615 0 3 0x4000082 wait syz-fuzzer
38030 245213 33615 0 3 0x4000082 kqread syz-fuzzer
38030 492136 33615 0 3 0x4000082 wait syz-fuzzer
38030 297417 33615 0 3 0x4000082 wait syz-fuzzer
33615 67479 93092 0 3 0x10008a sigsusp ksh
93092 283012 85788 0 3 0x9a kqread sshd
30762 408975 1 0 3 0x100083 ttyopn getty
85788 116145 1 0 3 0x88 kqread sshd
59545 321118 77269 74 3 0x1100092 bpf pflogd
77269 411876 1 0 3 0x80 netio pflogd
84077 315156 81319 73 3 0x1100090 kqread syslogd
81319 359473 1 0 3 0x100082 netio syslogd
98032 286312 1 0 3 0x100080 kqread resolvd
85520 327227 0 0 3 0x14200 bored smr
98835 506004 0 0 2 0x14200 zerothread
13028 129293 0 0 3 0x14200 aiodoned aiodoned
27530 477584 0 0 3 0x14200 syncer update
60396 324053 0 0 3 0x14200 cleaner cleaner
49008 275163 0 0 3 0x14200 reaper reaper
28344 38805 0 0 3 0x14200 pgdaemon pagedaemon
70463 446085 0 0 3 0x14200 bored viomb
90005 116741 0 0 3 0x40014200 acpi0 acpi0
24355 253539 0 0 3 0x40014200 idle1
35333 320630 0 0 3 0x14200 bored softnet
93608 402741 0 0 3 0x14200 bored softnet
78444 178830 0 0 3 0x14200 bored softnet
49630 71948 0 0 3 0x14200 bored softnet
19444 335280 0 0 3 0x14200 bored systqmp
42697 412221 0 0 3 0x14200 bored systq
*59418 120987 0 0 7 0x40014200 softclock
83898 71252 0 0 3 0x40014200 idle0
1 255366 0 0 3 0x80082 wait init
0 0 -1 0 3 0x10200 scheduler swapper
ddb{0}> show all locks
Process 23840 (syz-executor.5) thread 0xffff800027c06fc0 (27945)
exclusive rrwlock inode r = 0 (0xfffffd8067f424e8)
#0 witness_lock+0x44d
#1 rw_enter+0x3e1 sys/kern/kern_rwlock.c:310
#2 rrw_enter+0x8b sys/kern/kern_rwlock.c:465
#3 VOP_LOCK+0x87 sys/kern/vfs_vops.c:518
#4 ufs_ihashins+0x42 sys/ufs/ufs/ufs_ihash.c:140
#5 ffs_vget+0x141 sys/ufs/ffs/ffs_vfsops.c:1353
#6 ffs_inode_alloc+0x1be sys/ufs/ffs/ffs_alloc.c:394
#7 ufs_mkdir+0xf4 sys/ufs/ufs/ufs_vnops.c:1150
#8 VOP_MKDIR+0xbf sys/kern/vfs_vops.c:388
#9 domkdirat+0x121 sys/kern/vfs_syscalls.c:3112
#10 syscall+0x438 mi_syscall sys/sys/syscall_mi.h:101 [inline]
#10 syscall+0x438 sys/arch/amd64/amd64/trap.c:599
#11 Xsyscall+0x128
exclusive rrwlock inode r = 0 (0xfffffd8067f422c8)
#0 witness_lock+0x44d
#1 rw_enter+0x3e1 sys/kern/kern_rwlock.c:310
#2 rrw_enter+0x8b sys/kern/kern_rwlock.c:465
#3 VOP_LOCK+0x87 sys/kern/vfs_vops.c:518
#4 vn_lock+0x84 sys/kern/vfs_vnops.c:564
#5 vfs_lookup+0xd1 sys/kern/vfs_lookup.c:412
#6 namei+0x36a sys/kern/vfs_lookup.c:244
#7 domkdirat+0x75 sys/kern/vfs_syscalls.c:3097
#8 syscall+0x438 mi_syscall sys/sys/syscall_mi.h:101 [inline]
#8 syscall+0x438 sys/arch/amd64/amd64/trap.c:599
#9 Xsyscall+0x128
Process 59418 (softclock) thread 0xffff8000211e97a0 (120987)
exclusive rwlock netlock r = 0 (0xffffffff829de890)
#0 witness_lock+0x44d
#1 arptimer+0x22 sys/netinet/if_ether.c:132
#2 timeout_run+0xcc sys/kern/kern_timeout.c:653
#3 softclock_thread+0x134 sys/kern/kern_timeout.c:777
#4 proc_trampoline+0x1c
shared rwlock timeout r = 0 (0xffffffff8294c810)
#0 witness_lock+0x44d
#1 timeout_run+0xb7 sys/kern/kern_timeout.c:649
#2 softclock_thread+0x134 sys/kern/kern_timeout.c:777
#3 proc_trampoline+0x1c
exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82a8fca0)
#0 witness_lock+0x44d
#1 __mp_acquire_count+0x48 sys/kern/kern_lock.c:227
#2 mi_switch+0x3bb sys/kern/sched_bsd.c:415
#3 sleep_finish+0x180 sys/kern/kern_synch.c:417
#4 softclock_thread+0xd9 sys/kern/kern_timeout.c:772
#5 proc_trampoline+0x1c
ddb{0}> show malloc
Type InUse MemUse HighUse Limit Requests Type Lim
devbuf 10223 6498K 8084K 78643K 14811 0
pcb 13 16K 18K 78643K 1564 0
rtable 198 15K 15K 78643K 1965 0
ifaddr 145 31K 33K 78643K 963 0
sysctl 3 1K 1K 78643K 10 0
counters 62 36K 36K 78643K 700 0
ioctlops 0 0K 6K 78643K 4333 0
iov 0 0K 32K 78643K 1754 0
mount 1 1K 1K 78643K 1 0
log 0 0K 0K 78643K 4 0
vnodes 1789 112K 112K 78643K 7626 0
UFS quota 1 32K 32K 78643K 1 0
UFS mount 5 36K 36K 78643K 5 0
shm 2 1K 9K 78643K 104 0
VM map 2 1K 1K 78643K 2 0
sem 12 0K 1K 78643K 864 0
dirhash 12 2K 2K 78643K 12 0
ACPI 1697 195K 286K 78643K 12548 0
file desc 15 53K 81K 78643K 9002 0
sigio 0 0K 0K 78643K 165 0
proc 65 67K 115K 78643K 2010 0
subproc 104 6K 8K 78643K 558 0
NFS srvsock 1 0K 0K 78643K 1 0
NFS daemon 1 16K 16K 78643K 1 0
ip_moptions 4 0K 0K 78643K 4190 0
in_multi 83 5K 7K 78643K 687 0
ether_multi 1 0K 0K 78643K 60 0
mrt 1 0K 0K 78643K 13 0
ISOFS mount 1 32K 32K 78643K 1 0
MSDOSFS mount 1 16K 16K 78643K 1 0
ttys 175 784K 784K 78643K 175 0
exec 0 0K 1K 78643K 1990 0
pfkey data 0 0K 0K 78643K 10 0
tdb 3 0K 0K 78643K 3 0
pagedep 1 8K 8K 78643K 1 0
inodedep 1 32K 32K 78643K 1 0
newblk 1 0K 0K 78643K 1 0
VM swap 8 62K 64K 78643K 10 0
UVM amap 505 1071K 1073K 78643K 65035 0
UVM aobj 131 4K 4K 78643K 141 0
memdesc 1 4K 4K 78643K 1 0
crypto data 1 1K 1K 78643K 1 0
ip6_options 0 0K 0K 78643K 439 0
NDP 15 0K 2K 78643K 268 0
temp 149 4734K 5759K 78643K 103765 0
kqueue 6 10K 31K 78643K 755 0
SYN cache 2 16K 16K 78643K 2 0
ddb{0}> show all pools
Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
plcache 128 22 0 0 1 0 1 1 0 8 0
rtpcb 120 725 0 724 7 6 1 3 0 8 0
rtentry 112 569 0 482 4 0 4 4 0 8 0
unpcb 144 5750 0 5740 67 61 6 8 0 8 5
syncache 296 59 0 59 15 15 0 1 0 8 0
tcpqe 32 180 0 180 10 10 0 1 0 8 0
tcpcb 776 7741 0 7731 133 122 11 21 0 8 10
arp 120 86 0 71 1 0 1 1 0 8 0
inpcb 368 13211 0 13189 126 115 11 17 0 8 8
nd6 48 133 0 113 1 0 1 1 0 8 0
pkpcb 40 90 0 90 4 4 0 1 0 8 0
kcovpl 48 40 0 32 1 0 1 1 0 8 0
mppekey 1024 5 0 5 2 2 0 1 0 8 0
ppxss 1256 233 0 233 16 15 1 1 0 8 1
pppxif 1704 94 0 94 10 10 0 1 0 8 0
pfstscr 40 98 0 97 5 4 1 1 0 8 0
pffrag 232 16 0 15 6 5 1 1 0 482 0
pffrnode 88 16 0 15 6 5 1 1 0 8 0
pffrent 40 44 0 43 6 5 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
pfanchor 1280 221 0 16 19 1 18 18 0 8 0
pfqueue 264 35 0 35 1 1 0 1 0 8 0
pfstitem 24 10 0 8 3 2 1 1 0 8 0
pfstkey 120 114 0 112 5 4 1 1 0 8 0
pfstate 336 91 0 90 5 4 1 1 0 8 0
rttmr 136 3 0 3 1 1 0 1 0 8 0
art_heap8 4096 5 0 4 5 4 1 2 0 8 0
art_heap4 256 2618 0 2210 52 25 27 30 0 8 0
art_table 32 2623 0 2214 4 0 4 4 0 8 0
art_node 16 568 0 492 1 0 1 1 0 8 0
semupl 112 1 0 1 1 1 0 1 0 8 0
semapl 112 862 0 852 1 0 1 1 0 8 0
shmpl 112 138 0 10 4 0 4 4 0 8 0
dirhash 1024 17 0 0 3 0 3 3 0 8 0
dino2pl 256 13392 0 11887 95 0 95 95 0 8 0
ffsino 272 13392 0 11887 101 0 101 101 0 8 0
nchpl 144 25731 0 25201 63 39 24 63 0 8 0
rtmask 32 6 0 6 2 2 0 1 0 8 0
uvmvnodes 80 6254 0 0 128 0 128 128 0 8 0
vnodes 216 6254 0 0 348 0 348 348 0 8 0
namei 1024 92543 0 92542 7 6 1 2 0 8 0
percpumem 16 362 0 319 1 0 1 1 0 8 0
vcpupl 2048 76 0 0 10 0 10 10 0 8 0
vmpool 568 145 0 69 7 1 6 6 0 8 0
kstatmem 264 362 0 332 4 1 3 3 0 8 0
scxspl 216 84718 0 84718 20 19 1 5 0 8 1
plimitpl 152 1376 0 1361 1 0 1 1 0 8 0
sigapl 424 9322 0 9258 11 3 8 8 0 8 0
futexpl 64 78045 0 78043 2 1 1 1 0 8 0
knotepl 120 746 0 0 16 1 15 16 0 8 0
kqueuepl 216 1618 0 1613 19 18 1 6 0 8 0
pipepl 320 1709 0 1680 52 49 3 8 0 8 0
fdescpl 496 9240 0 9215 5 1 4 5 0 8 0
filepl 152 64891 0 64658 106 88 18 19 0 8 8
lockfpl 104 2660 0 2657 8 7 1 2 0 8 0
lockfspl 48 691 0 689 1 0 1 1 0 8 0
sessionpl 144 56 0 40 1 0 1 1 0 8 0
pgrppl 48 63 0 47 1 0 1 1 0 8 0
ucredpl 104 7755 0 7732 1 0 1 1 0 8 0
zombiepl 144 9261 0 9258 1 0 1 1 0 8 0
processpl 1064 9322 0 9258 5 0 5 5 0 8 0
procpl 672 27352 0 27261 17 8 9 10 0 8 0
srpgc 96 44 0 44 13 13 0 1 0 8 0
sosppl 168 71 0 71 10 10 0 1 0 8 0
sockpl 488 19784 0 19751 324 291 33 33 0 8 28
mcl64k 65536 33 0 0 4 1 3 3 0 8 0
mcl16k 16384 17 0 0 3 0 3 3 0 8 0
mcl12k 12288 17 0 0 2 0 2 2 0 8 0
mcl9k 9216 17 0 0 2 0 2 2 0 8 0
mcl8k 8192 35 0 0 5 2 3 3 0 8 0
mcl4k 4096 25 0 0 3 0 3 3 0 8 0
mcl2k2 2112 7 0 0 1 0 1 1 0 8 0
mcl2k 2048 422 0 0 49 17 32 49 0 8 0
mtagpl 96 62 0 0 2 0 2 2 0 8 0
mbufpl 256 1502 0 0 68 0 68 68 0 8 0
bufpl 288 19745 0 13414 453 0 453 453 0 8 0
anonpl 24 1882106 0 1865172 207 79 128 132 0 186 9
amapchunkpl 152 181750 0 180962 67 26 41 45 0 158 3
amappl16 200 16272 0 15746 94 65 29 41 0 8 0
amappl15 192 10 0 10 2 2 0 1 0 8 0
amappl14 184 252 0 241 2 1 1 2 0 8 0
amappl13 176 15 0 14 1 0 1 1 0 8 0
amappl12 168 809 0 806 1 0 1 1 0 8 0
amappl11 160 69 0 59 1 0 1 1 0 8 0
amappl10 152 59 0 49 1 0 1 1 0 8 0
amappl9 144 1046 0 1044 1 0 1 1 0 8 0
amappl8 136 447 0 341 4 0 4 4 0 8 0
amappl7 128 91 0 72 1 0 1 1 0 8 0
amappl6 120 683 0 664 2 1 1 2 0 8 0
amappl5 112 234 0 226 1 0 1 1 0 8 0
amappl4 104 1095 0 1060 2 1 1 2 0 8 0
amappl3 96 27753 0 27705 2 0 2 2 0 8 0
amappl2 88 10057 0 9999 3 1 2 3 0 8 0
amappl1 80 212811 0 212151 27 12 15 22 0 8 0
amappl 88 64150 0 63880 8 1 7 7 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 128 253 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 72 140 0 10 3 0 3 3 0 8 0
uaddrrnd 24 9385 0 9284 1 0 1 1 0 8 0
uaddrbest 32 2 0 0 1 0 1 1 0 8 0
uaddr 24 9385 0 9284 1 0 1 1 0 8 0
vmmpekpl 168 76406 0 76324 4 0 4 4 0 8 0
vmmpepl 168 853427 0 850811 229 100 129 149 0 357 0
vmsppl 368 9384 0 9284 11 1 10 10 0 8 0
rwobjpl 56 232370 0 224295 124 10 114 114 0 8 0
pdppl 4096 18777 0 18644 578 439 139 139 0 8 6
pvpl 32 3753366 0 3730976 475 240 235 260 0 265 36
pmappl 248 9384 0 9284 8 1 7 7 0 8 0
extentpl 40 56 0 38 1 0 1 1 0 8 0
phpool 112 1599 0 633 28 0 28 28 0 8 0
ddb{0}> machine ddbcpu 0
Invalid cpu 0
ddb{0}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437
panic(ffffffff825af7a0) at panic+0x177 sys/kern/subr_prf.c:198
__assert(ffffffff82622d21,ffffffff8261f053,308,ffffffff8257c3e4) at __assert+0x25 sys/kern/subr_prf.c:157
arptfree(fffffd806843a5c0) at arptfree+0x12e sys/netinet/if_ether.c:776
arptimer(ffffffff82a36328) at arptimer+0x88 sys/netinet/if_ether.c:135
timeout_run(ffffffff82a36328) at timeout_run+0xcc sys/kern/kern_timeout.c:653
softclock_thread(ffff8000211e97a0) at softclock_thread+0x134 sys/kern/kern_timeout.c:777
end trace frame: 0x0, count: -7
ddb{0}> machine ddbcpu 1
Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp
x86_ipi_db(ffff800020dd8ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:393
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+0xb sys/dev/kcov.c:144
syscall(ffff80002e4afb30) at syscall+0x424 mi_syscall sys/sys/syscall_mi.h:101 [inline]
syscall(ffff80002e4afb30) at syscall+0x424 sys/arch/amd64/amd64/trap.c:599
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffff83010, count: 9
ddb{1}> trace
x86_ipi_db(ffff800020dd8ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:393
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+0xb sys/dev/kcov.c:144
syscall(ffff80002e4afb30) at syscall+0x424 mi_syscall sys/sys/syscall_mi.h:101 [inline]
syscall(ffff80002e4afb30) at syscall+0x424 sys/arch/amd64/amd64/trap.c:599
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffff83010, count: -6


---
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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.