assert "mhead->m_flags & M_PKTHDR" failed in switchctl.c (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 151ba632 Pass a NULL instead of zeroed out va_list from do..
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=165ef5d6100000
kernel config: https://syzkaller.appspot.com/x/.config?x=bf87b6915a88cd0d
dashboard link: https://syzkaller.appspot.com/bug?extid=e075f98aefddd31d9b99

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+e075f9...@syzkaller.appspotmail.com

panic: kernel diagnostic assertion "mhead->m_flags & M_PKTHDR" failed: file "/syzkaller/managers/multicore/kernel/sys/net/switchctl.c", line 245
Stopped at db_enter+0x18: addq $0x8,%rsp
TID PID UID PRFLAGS PFLAGS CPU COMMAND
518405 29097 0 0 0 0 syz-executor.0
*437646 59756 0 0 0x4000000 1K syz-executor.1
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff821ff832) at panic+0x15c sys/kern/subr_prf.c:207
__assert(ffffffff82254ed0,ffffffff82216e99,f5,ffffffff821dd50d) at __assert+0x2b sys/kern/subr_prf.c:154
switchwrite(86128,ffff800022034f70,1) at switchwrite+0x44f sys/net/switchctl.c:245
spec_write(ffff800022034d40) at spec_write+0xd4 sys/kern/spec_vnops.c:309
VOP_WRITE(fffffd8064d4e0e8,ffff800022034f70,1,fffffd807f7bf840) at VOP_WRITE+0xc6 sys/kern/vfs_vops.c:268
vn_write(fffffd806cb81b58,ffff800022034f70,1) at vn_write+0x198 sys/kern/vfs_vnops.c:414
dofilewritev(ffff800020ec69d8,3,ffff800022034f70,1,ffff800022035060) at dofilewritev+0x1b6 sys/kern/sys_generic.c:365
sys_pwritev(ffff800020ec69d8,ffff800022035018,ffff800022035060) at sys_pwritev+0xb8 sys/kern/vfs_syscalls.c:3338
syscall(ffff8000220350e0) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff8000220350e0) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x3ae8f473900, count: 4
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 "mhead->m_flags & M_PKTHDR" failed: file "/syzkaller/managers/multicore/kernel/sys/net/switchctl.c", line 245
ddb{1}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff821ff832) at panic+0x15c sys/kern/subr_prf.c:207
__assert(ffffffff82254ed0,ffffffff82216e99,f5,ffffffff821dd50d) at __assert+0x2b sys/kern/subr_prf.c:154
switchwrite(86128,ffff800022034f70,1) at switchwrite+0x44f sys/net/switchctl.c:245
spec_write(ffff800022034d40) at spec_write+0xd4 sys/kern/spec_vnops.c:309
VOP_WRITE(fffffd8064d4e0e8,ffff800022034f70,1,fffffd807f7bf840) at VOP_WRITE+0xc6 sys/kern/vfs_vops.c:268
vn_write(fffffd806cb81b58,ffff800022034f70,1) at vn_write+0x198 sys/kern/vfs_vnops.c:414
dofilewritev(ffff800020ec69d8,3,ffff800022034f70,1,ffff800022035060) at dofilewritev+0x1b6 sys/kern/sys_generic.c:365
sys_pwritev(ffff800020ec69d8,ffff800022035018,ffff800022035060) at sys_pwritev+0xb8 sys/kern/vfs_syscalls.c:3338
syscall(ffff8000220350e0) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff8000220350e0) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x3ae8f473900, count: -11
ddb{1}> show registers
rdi 0
rsi 0x1
rbp 0xffff800022034b40
rbx 0xffff800022034bf0
rdx 0x8b
rcx 0x2
rax 0x1
r8 0xffffffff8212b2ff kprintf+0x16f
r9 0x1
r10 0x2
r11 0x3c0e5c53e0f988b6
r12 0x3000000008
r13 0xffff800022034b50
r14 0x100
r15 0x1
rip 0xffffffff81cb79c8 db_enter+0x18
cs 0x8
rflags 0x246
rsp 0xffff800022034b30
ss 0x10
db_enter+0x18: addq $0x8,%rsp
ddb{1}> show proc
PROC (syz-executor.1) pid=437646 stat=onproc
flags process=0 proc=4000000<THREAD>
pri=73, usrpri=73, nice=20
forw=0xffffffffffffffff, list=0xffff800020ec7878,0xffffffff826aa8a0
process=0xffff80002200af90 user=0xffff800022030000, vmspace=0xfffffd807f000730
estcpu=36, cpticks=2, pctcpu=0.0
user=0, sys=2, intr=0
ddb{1}> ps
PID TID PPID UID S FLAGS WAIT COMMAND
29097 518405 678 0 7 0 syz-executor.0
29097 39003 678 0 3 0x4000080 fsleep syz-executor.0
59756 189982 77193 0 2 0 syz-executor.1
59756 460649 77193 0 3 0x4000080 fsleep syz-executor.1
*59756 437646 77193 0 7 0x4000000 syz-executor.1
42830 28717 0 0 3 0x14200 bored sosplice
77193 57681 12252 0 3 0x82 nanosleep syz-executor.1
36324 214489 0 0 3 0x14280 nfsidl nfsio
50194 440661 0 0 3 0x14280 nfsidl nfsio
63579 124837 0 0 3 0x14280 nfsidl nfsio
53684 127903 0 0 3 0x14280 nfsidl nfsio
9393 227167 0 0 3 0x14280 nfsidl nfsio
86781 472940 0 0 3 0x14280 nfsidl nfsio
90609 408341 0 0 3 0x14280 nfsidl nfsio
32509 219793 0 0 3 0x14280 nfsidl nfsio
157 365026 0 0 3 0x14280 nfsidl nfsio
70529 14029 0 0 3 0x14280 nfsidl nfsio
20702 343312 0 0 3 0x14280 nfsidl nfsio
21473 298175 0 0 3 0x14280 nfsidl nfsio
56772 452925 0 0 3 0x14280 nfsidl nfsio
27343 353255 0 0 3 0x14280 nfsidl nfsio
79936 494103 0 0 3 0x14280 nfsidl nfsio
57619 296939 0 0 3 0x14280 nfsidl nfsio
91149 65041 0 0 3 0x14280 nfsidl nfsio
96603 275820 0 0 3 0x14280 nfsidl nfsio
73232 480612 0 0 3 0x14280 nfsidl nfsio
34513 277774 0 0 3 0x14280 nfsidl nfsio
678 135559 12252 0 3 0x82 nanosleep syz-executor.0
12252 348834 96426 0 3 0x82 thrsleep syz-fuzzer
12252 21419 96426 0 3 0x4000082 nanosleep syz-fuzzer
12252 464185 96426 0 3 0x4000082 thrsleep syz-fuzzer
12252 240567 96426 0 3 0x4000082 thrsleep syz-fuzzer
12252 233201 96426 0 3 0x4000082 thrsleep syz-fuzzer
12252 134540 96426 0 3 0x4000082 thrsleep syz-fuzzer
12252 285370 96426 0 3 0x4000082 thrsleep syz-fuzzer
12252 149573 96426 0 3 0x4000082 thrsleep syz-fuzzer
12252 288597 96426 0 3 0x4000082 kqread syz-fuzzer
12252 194852 96426 0 3 0x4000082 thrsleep syz-fuzzer
96426 473060 72229 0 3 0x10008a pause ksh
72229 75416 76363 0 3 0x92 select sshd
41356 237291 1 0 3 0x100083 ttyin getty
76363 55121 1 0 3 0x80 select sshd
954 253174 16282 74 3 0x100092 bpf pflogd
16282 440884 1 0 3 0x80 netio pflogd
99198 23884 91154 73 3 0x100090 kqread syslogd
91154 518774 1 0 3 0x100082 netio syslogd
50240 494774 1 77 3 0x100090 poll dhclient
13126 470310 1 0 3 0x80 poll dhclient
89227 459454 0 0 3 0x14200 bored smr
35714 20650 0 0 2 0x14200 zerothread
22175 254766 0 0 3 0x14200 aiodoned aiodoned
5307 291578 0 0 3 0x14200 syncer update
96653 314058 0 0 3 0x14200 cleaner cleaner
29929 81902 0 0 3 0x14200 reaper reaper
35400 205363 0 0 3 0x14200 pgdaemon pagedaemon
28013 274151 0 0 3 0x14200 bored crynlk
7548 497535 0 0 3 0x14200 bored crypto
44131 29592 0 0 3 0x40014200 acpi0 acpi0
1043 315059 0 0 3 0x40014200 idle1
36199 286273 0 0 3 0x14200 bored softnet
91670 108651 0 0 3 0x14200 bored systqmp
9272 189422 0 0 3 0x14200 bored systq
21039 384616 0 0 3 0x40014200 bored softclock
91072 381375 0 0 3 0x40014200 idle0
1 440985 0 0 3 0x82 wait init
0 0 -1 0 3 0x10200 scheduler swapper
ddb{1}> show all locks
Process 59756 (syz-executor.1) thread 0xffff800020ec69d8 (437646)
exclusive kernel_lock &kernel_lock r = 0 (0xffffffff826906e8)
#0 witness_lock+0x4c7 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0 witness_lock+0x4c7 sys/kern/subr_witness.c:1164
#1 vn_write+0x42 sys/kern/vfs_vnops.c:399
#2 dofilewritev+0x1b6 sys/kern/sys_generic.c:365
#3 sys_pwritev+0xb8 sys/kern/vfs_syscalls.c:3338
#4 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#4 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
#5 Xsyscall+0x128
ddb{1}> show malloc
Type InUse MemUse HighUse Limit Requests Type Lim
devbuf 9536 6556K 7331K 78643K 11936 0
pcb 13 8K 8K 78643K 55 0
rtable 116 4K 4K 78643K 294 0
ifaddr 74 14K 14K 78643K 96 0
counters 43 33K 34K 78643K 49 0
ioctlops 0 0K 4K 78643K 1480 0
iov 1 12K 16K 78643K 37 0
mount 1 1K 1K 78643K 1 0
vnodes 1228 77K 77K 78643K 1566 0
UFS quota 1 32K 32K 78643K 1 0
UFS mount 5 36K 36K 78643K 5 0
shm 2 1K 5K 78643K 8 0
VM map 2 1K 1K 78643K 2 0
sem 12 0K 0K 78643K 38 0
dirhash 12 2K 2K 78643K 12 0
ACPI 1824 197K 290K 78643K 13058 0
file desc 6 17K 25K 78643K 242 0
sigio 0 0K 0K 78643K 4 0
proc 62 63K 95K 78643K 501 0
subproc 32 2K 2K 78643K 51 0
NFS srvsock 1 0K 0K 78643K 1 0
NFS daemon 1 16K 16K 78643K 1 0
ip_moptions 0 0K 0K 78643K 66 0
in_multi 33 2K 2K 78643K 58 0
ether_multi 1 0K 0K 78643K 5 0
mrt 0 0K 0K 78643K 4 0
ISOFS mount 1 32K 32K 78643K 1 0
MSDOSFS mount 1 16K 16K 78643K 1 0
ttys 37 175K 175K 78643K 37 0
exec 0 0K 1K 78643K 259 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 133 24K 24K 78643K 1750 0
UVM aobj 12 4K 4K 78643K 22 0
memdesc 1 4K 4K 78643K 1 0
crypto data 1 1K 1K 78643K 1 0
ip6_options 0 0K 0K 78643K 28 0
NDP 13 0K 0K 78643K 22 0
temp 107 3035K 3099K 78643K 4698 0
kqueue 3 4K 8K 78643K 20 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 9 0 2 1 0 1 1 0 8 0
plcache 128 20 0 0 1 0 1 1 0 8 0
rtpcb 80 45 0 43 1 0 1 1 0 8 0
rtentry 112 63 0 15 2 0 2 2 0 8 0
unpcb 120 199 0 189 1 0 1 1 0 8 0
syncache 264 5 0 5 2 1 1 1 0 8 1
tcpqe 32 182 0 182 1 1 0 1 0 8 0
tcpcb 544 90 0 86 1 0 1 1 0 8 0
inpcb 280 561 0 548 2 0 2 2 0 8 1
rttmr 72 1 0 1 1 0 1 1 0 8 1
nd6 48 11 0 4 1 0 1 1 0 8 0
ppxss 1128 1 0 1 1 1 0 1 0 8 0
pffrent 40 2 0 2 1 1 0 1 0 8 0
pfosfp 40 846 0 423 5 0 5 5 0 8 0
pfosfpen 112 1428 0 714 21 0 21 21 0 8 0
pfstitem 24 32 0 2 1 0 1 1 0 8 0
pfstkey 112 32 0 2 1 0 1 1 0 8 0
pfstate 328 32 0 2 3 0 3 3 0 8 0
pfrule 1360 21 0 16 2 1 1 2 0 8 0
art_heap8 4096 1 0 0 1 0 1 1 0 8 0
art_heap4 256 284 0 59 15 0 15 15 0 8 0
art_table 32 285 0 59 2 0 2 2 0 8 0
art_node 16 62 0 18 1 0 1 1 0 8 0
sysvmsgpl 40 8 0 3 1 0 1 1 0 8 0
semupl 112 2 0 2 1 1 0 1 0 8 0
semapl 112 34 0 24 1 0 1 1 0 8 0
shmpl 112 20 0 10 1 0 1 1 0 8 0
dirhash 1024 17 0 0 3 0 3 3 0 8 0
dino2pl 256 1704 0 298 89 0 89 89 0 8 0
ffsino 272 1704 0 298 94 0 94 94 0 8 0
nchpl 144 2198 0 601 60 0 60 60 0 8 0
uvmvnodes 72 2063 0 0 38 0 38 38 0 8 0
vnodes 208 2063 0 0 109 0 109 109 0 8 0
namei 1024 6168 0 6168 1 0 1 1 0 8 1
percpumem 16 35 0 3 1 0 1 1 0 8 0
scxspl 192 5823 0 5823 8 3 5 7 0 8 5
plimitpl 152 36 0 28 1 0 1 1 0 8 0
sigapl 424 475 0 422 6 0 6 6 0 8 0
futexpl 56 4048 0 4046 1 0 1 1 0 8 0
knotepl 112 87 0 68 1 0 1 1 0 8 0
kqueuepl 144 32 0 30 1 0 1 1 0 8 0
pipelkpl 48 111 0 101 1 0 1 1 0 8 0
pipepl 120 222 0 203 1 0 1 1 0 8 0
fdescpl 496 439 0 422 3 0 3 3 0 8 0
filepl 152 2789 0 2686 5 0 5 5 0 8 1
lockfpl 104 17 0 16 1 0 1 1 0 8 0
lockfspl 48 9 0 8 1 0 1 1 0 8 0
sessionpl 112 19 0 8 1 0 1 1 0 8 0
pgrppl 48 19 0 8 1 0 1 1 0 8 0
ucredpl 96 158 0 149 1 0 1 1 0 8 0
zombiepl 144 422 0 422 1 0 1 1 0 8 1
processpl 984 475 0 422 7 0 7 7 0 8 0
procpl 624 949 0 884 6 0 6 6 0 8 1
sosppl 128 1 0 1 1 0 1 1 0 8 1
sockpl 400 806 0 785 4 0 4 4 0 8 1
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 3 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 3 0 0 1 0 1 1 0 8 0
mcl2k2 2112 1 0 0 1 0 1 1 0 8 0
mcl2k 2048 227 0 0 28 0 28 28 0 8 0
mtagpl 80 80 0 0 2 0 2 2 0 8 0
mbufpl 256 389 0 0 24 0 24 24 0 8 0
bufpl 280 3622 0 133 250 0 250 250 0 8 0
anonpl 16 54993 0 40303 61 1 60 60 0 124 0
amapchunkpl 152 2296 0 2155 7 0 7 7 0 158 0
amappl16 192 1726 0 921 41 0 41 41 0 8 0
amappl15 184 50 0 48 2 1 1 1 0 8 0
amappl14 176 28 0 22 1 0 1 1 0 8 0
amappl13 168 51 0 47 1 0 1 1 0 8 0
amappl12 160 7 0 4 1 0 1 1 0 8 0
amappl11 152 107 0 89 1 0 1 1 0 8 0
amappl10 144 165 0 160 1 0 1 1 0 8 0
amappl9 136 389 0 388 1 0 1 1 0 8 0
amappl8 128 386 0 347 2 0 2 2 0 8 0
amappl7 120 267 0 252 1 0 1 1 0 8 0
amappl6 112 81 0 70 1 0 1 1 0 8 0
amappl5 104 277 0 262 1 0 1 1 0 8 0
amappl4 96 553 0 521 1 0 1 1 0 8 0
amappl3 88 110 0 104 1 0 1 1 0 8 0
amappl2 80 2496 0 2417 2 0 2 2 0 8 0
amappl1 72 19629 0 19176 23 13 10 18 0 8 0
amappl 80 1194 0 1147 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 21 0 10 1 0 1 1 0 8 0
uaddrrnd 24 439 0 422 1 0 1 1 0 8 0
uaddrbest 32 2 0 0 1 0 1 1 0 8 0
uaddr 24 439 0 422 1 0 1 1 0 8 0
vmmpekpl 168 7345 0 7304 2 0 2 2 0 8 0
vmmpepl 168 60322 0 58251 120 4 116 116 0 357 25
vmsppl 368 438 0 422 2 0 2 2 0 8 0
pdppl 4096 886 0 844 6 0 6 6 0 8 0
pvpl 32 183793 0 165620 149 2 147 149 0 265 0
pmappl 232 438 0 422 2 1 1 2 0 8 0
extentpl 40 53 0 36 1 0 1 1 0 8 0
phpool 112 282 0 3 8 0 8 8 0 8 0
ddb{1}> machine ddbcpu 0
Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp
x86_ipi_db(ffffffff82519ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:352
x86_ipi_handler() at x86_ipi_handler+0xc6 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23
__mp_lock(ffffffff826904e0) at __mp_lock+0x12e __mp_lock_spin sys/kern/kern_lock.c:116 [inline]
__mp_lock(ffffffff826904e0) at __mp_lock+0x12e sys/kern/kern_lock.c:147
softintr_dispatch(0) at softintr_dispatch+0x4e sys/arch/amd64/amd64/softintr.c:89
Xsoftclock() at Xsoftclock+0x1f
__mp_lock(ffffffff826904e0) at __mp_lock+0x127 __mp_lock_spin sys/kern/kern_lock.c:116 [inline]
__mp_lock(ffffffff826904e0) at __mp_lock+0x127 sys/kern/kern_lock.c:147
pageflttrap(ffff800022023690,1) at pageflttrap+0x7f sys/arch/amd64/amd64/trap.c:180
usertrap(ffff800022023690) at usertrap+0x21a sys/arch/amd64/amd64/trap.c:384
recall_trap() at recall_trap+0x8
end of kernel
end trace frame: 0x7f7ffffc5e60, count: 5
ddb{0}> trace
x86_ipi_db(ffffffff82519ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:352
x86_ipi_handler() at x86_ipi_handler+0xc6 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23
__mp_lock(ffffffff826904e0) at __mp_lock+0x12e __mp_lock_spin sys/kern/kern_lock.c:116 [inline]
__mp_lock(ffffffff826904e0) at __mp_lock+0x12e sys/kern/kern_lock.c:147
softintr_dispatch(0) at softintr_dispatch+0x4e sys/arch/amd64/amd64/softintr.c:89
Xsoftclock() at Xsoftclock+0x1f
__mp_lock(ffffffff826904e0) at __mp_lock+0x127 __mp_lock_spin sys/kern/kern_lock.c:116 [inline]
__mp_lock(ffffffff826904e0) at __mp_lock+0x127 sys/kern/kern_lock.c:147
pageflttrap(ffff800022023690,1) at pageflttrap+0x7f sys/arch/amd64/amd64/trap.c:180
usertrap(ffff800022023690) at usertrap+0x21a sys/arch/amd64/amd64/trap.c:384
recall_trap() at recall_trap+0x8
end of kernel
end trace frame: 0x7f7ffffc5e60, 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(ffffffff821ff832) at panic+0x15c sys/kern/subr_prf.c:207
__assert(ffffffff82254ed0,ffffffff82216e99,f5,ffffffff821dd50d) at __assert+0x2b sys/kern/subr_prf.c:154
switchwrite(86128,ffff800022034f70,1) at switchwrite+0x44f sys/net/switchctl.c:245
spec_write(ffff800022034d40) at spec_write+0xd4 sys/kern/spec_vnops.c:309
VOP_WRITE(fffffd8064d4e0e8,ffff800022034f70,1,fffffd807f7bf840) at VOP_WRITE+0xc6 sys/kern/vfs_vops.c:268
vn_write(fffffd806cb81b58,ffff800022034f70,1) at vn_write+0x198 sys/kern/vfs_vnops.c:414
dofilewritev(ffff800020ec69d8,3,ffff800022034f70,1,ffff800022035060) at dofilewritev+0x1b6 sys/kern/sys_generic.c:365
sys_pwritev(ffff800020ec69d8,ffff800022035018,ffff800022035060) at sys_pwritev+0xb8 sys/kern/vfs_syscalls.c:3338
syscall(ffff8000220350e0) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff8000220350e0) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x3ae8f473900, count: 4
ddb{1}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff821ff832) at panic+0x15c sys/kern/subr_prf.c:207
__assert(ffffffff82254ed0,ffffffff82216e99,f5,ffffffff821dd50d) at __assert+0x2b sys/kern/subr_prf.c:154
switchwrite(86128,ffff800022034f70,1) at switchwrite+0x44f sys/net/switchctl.c:245
spec_write(ffff800022034d40) at spec_write+0xd4 sys/kern/spec_vnops.c:309
VOP_WRITE(fffffd8064d4e0e8,ffff800022034f70,1,fffffd807f7bf840) at VOP_WRITE+0xc6 sys/kern/vfs_vops.c:268
vn_write(fffffd806cb81b58,ffff800022034f70,1) at vn_write+0x198 sys/kern/vfs_vnops.c:414
dofilewritev(ffff800020ec69d8,3,ffff800022034f70,1,ffff800022035060) at dofilewritev+0x1b6 sys/kern/sys_generic.c:365
sys_pwritev(ffff800020ec69d8,ffff800022035018,ffff800022035060) at sys_pwritev+0xb8 sys/kern/vfs_syscalls.c:3338
syscall(ffff8000220350e0) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff8000220350e0) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x3ae8f473900, count: -11


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