login: panic: kernel diagnostic assertion "TAILQ_EMPTY(&kq->kq_head)" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_event.c", line 1268
Stopped at db_enter+0x18: addq $0x8,%rsp
TID PID UID PRFLAGS PFLAGS CPU COMMAND
197323 51321 0 0x2 0 0 syz-executor0300
*112919 51321 0 0x2 0x4000000 1K syz-executor0300
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff823c3c11) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242d86c,ffffffff82425328,4f4,ffffffff823ad335) at __assert+0x2b sys/kern/subr_prf.c:162
kqueue_terminate(0,fffffd806e92ebd0) at kqueue_terminate+0x152 sys/kern/kern_event.c:1268
kqueue_close(fffffd807bacfa18,ffff8000ffff6010) at kqueue_close+0x40 sys/kern/kern_event.c:1286
fdrop(fffffd807bacfa18,ffff8000ffff6010) at fdrop+0xc2 sys/kern/kern_descrip.c:1279
closef(fffffd807bacfa18,ffff8000ffff6010) at closef+0x11c sys/kern/kern_descrip.c:1263
finishdup(ffff8000ffff6010,fffffd807bacf1c8,4,3,ffff800021263ac0,2) at finishdup+0x321 sys/kern/kern_descrip.c:691
dodup3(ffff8000ffff6010,4,3,0,ffff800021263ac0) at dodup3+0x5cf sys/kern/kern_descrip.c:397
syscall(ffff800021263b40) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800021263b40) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x553cbc72400, 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 "TAILQ_EMPTY(&kq->kq_head)" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_event.c", line 1268
ddb{1}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff823c3c11) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242d86c,ffffffff82425328,4f4,ffffffff823ad335) at __assert+0x2b sys/kern/subr_prf.c:162
kqueue_terminate(0,fffffd806e92ebd0) at kqueue_terminate+0x152 sys/kern/kern_event.c:1268
kqueue_close(fffffd807bacfa18,ffff8000ffff6010) at kqueue_close+0x40 sys/kern/kern_event.c:1286
fdrop(fffffd807bacfa18,ffff8000ffff6010) at fdrop+0xc2 sys/kern/kern_descrip.c:1279
closef(fffffd807bacfa18,ffff8000ffff6010) at closef+0x11c sys/kern/kern_descrip.c:1263
finishdup(ffff8000ffff6010,fffffd807bacf1c8,4,3,ffff800021263ac0,2) at finishdup+0x321 sys/kern/kern_descrip.c:691
dodup3(ffff8000ffff6010,4,3,0,ffff800021263ac0) at dodup3+0x5cf sys/kern/kern_descrip.c:397
syscall(ffff800021263b40) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800021263b40) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x553cbc72400, count: -11
ddb{1}> show registers
rdi 0
rsi 0x1
rbp 0xffff8000212636e0
rbx 0xffff8000212636f0
rdx 0x8b
rcx 0x2
rax 0x1
r8 0xffffffff821c43c5 kprintf+0x145
r9 0x1
r10 0xcb6961b596649ad8
r11 0x16407f50b9183eb9
r12 0x3000000008
r13 0xffff800021263790
r14 0x100
r15 0x1
rip 0xffffffff81df8258 db_enter+0x18
cs 0x8
rflags 0x246
rsp 0xffff8000212636d0
ss 0x10
db_enter+0x18: addq $0x8,%rsp
ddb{1}> show proc
PROC (syz-executor0300) pid=112919 stat=onproc
flags process=2<EXEC,8ORPHAN> proc=4000000<THREAD>
pri=51, usrpri=52, nice=20
forw=0xffffffffffffffff, list=0xffff8000ffff6a90,0xffffffff828cc870
process=0xffff800021237b20 user=0xffff80002125e000, vmspace=0xfffffd806e958b88
estcpu=2, cpticks=2, pctcpu=0.0
user=0, sys=2, intr=0
ddb{1}> ps
PID TID PPID UID S FLAGS WAIT COMMAND
51321 197323 50703 0 7 0x2 syz-executor0300
51321 190353 50703 0 3 0x4000082 kqread syz-executor0300
*51321 112919 50703 0 7 0x4000002 syz-executor0300
50703 149745 11815 0 3 0x10008a sigsusp ksh
11815 390694 73368 0 3 0x92 select sshd
62372 290428 1 0 3 0x100083 ttyin getty
73368 245579 1 0 3 0x80 select sshd
35433 110868 59713 74 3 0x100092 bpf pflogd
59713 265960 1 0 3 0x80 netio pflogd
54099 272565 9666 73 3 0x100090 kqread syslogd
9666 318417 1 0 3 0x100082 netio syslogd
16601 107028 1 77 3 0x100090 poll dhclient
84410 219328 1 0 3 0x80 poll dhclient
62790 124690 0 0 3 0x14200 bored smr
66871 59757 0 0 3 0x14200 pgzero zerothread
30331 477396 0 0 3 0x14200 aiodoned aiodoned
81708 505581 0 0 3 0x14200 syncer update
95402 453358 0 0 3 0x14200 cleaner cleaner
13988 384572 0 0 3 0x14200 reaper reaper
14947 89188 0 0 3 0x14200 pgdaemon pagedaemon
47789 474653 0 0 3 0x14200 bored crynlk
32799 102920 0 0 3 0x14200 bored crypto
69885 236507 0 0 3 0x14200 bored viomb
13609 335168 0 0 3 0x40014200 acpi0 acpi0
11157 252716 0 0 3 0x40014200 idle1
18238 84317 0 0 3 0x14200 bored softnet
78028 426606 0 0 3 0x14200 bored systqmp
65747 192525 0 0 3 0x14200 bored systq
24956 207493 0 0 3 0x40014200 bored softclock
40753 260519 0 0 3 0x40014200 idle0
1 466301 0 0 3 0x82 wait init
0 0 -1 0 3 0x10200 scheduler swapper
ddb{1}> show all locks
Process 51321 (syz-executor0300) thread 0xffff8000ffff6010 (112919)
exclusive kernel_lock &kernel_lock r = 0 (0xffffffff828cca98)
#0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0 witness_lock+0x4b0 sys/kern/subr_witness.c:1176
#1 kqueue_close+0x2d sys/kern/kern_event.c:1284
#2 fdrop+0xc2 sys/kern/kern_descrip.c:1279
#3 closef+0x11c sys/kern/kern_descrip.c:1263
#4 finishdup+0x321 sys/kern/kern_descrip.c:691
#5 dodup3+0x5cf sys/kern/kern_descrip.c:397
#6 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#6 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590
#7 Xsyscall+0x128
ddb{1}> show malloc
Type InUse MemUse HighUse Limit Requests Type Lim
devbuf 9475 6411K 6412K 78643K 10565 0
pcb 13 8K 8K 78643K 13 0
rtable 61 2K 2K 78643K 127 0
ifaddr 29 8K 8K 78643K 30 0
counters 40 33K 33K 78643K 40 0
ioctlops 0 0K 4K 78643K 1467 0
mount 1 1K 1K 78643K 1 0
vnodes 1183 74K 75K 78643K 1188 0
UFS quota 1 32K 32K 78643K 1 0
UFS mount 5 36K 36K 78643K 5 0
shm 2 1K 1K 78643K 2 0
VM map 2 1K 1K 78643K 2 0
sem 2 0K 0K 78643K 2 0
dirhash 12 2K 2K 78643K 12 0
ACPI 1697 195K 286K 78643K 12598 0
file desc 1 0K 0K 78643K 1 0
proc 59 63K 71K 78643K 367 0
NFS srvsock 1 0K 0K 78643K 1 0
NFS daemon 1 16K 16K 78643K 1 0
in_multi 11 0K 0K 78643K 11 0
ether_multi 1 0K 0K 78643K 1 0
ISOFS mount 1 32K 32K 78643K 1 0
MSDOSFS mount 1 16K 16K 78643K 1 0
ttys 19 95K 95K 78643K 19 0
exec 0 0K 2K 78643K 302 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 38 2K 2K 78643K 596 0
UVM aobj 3 2K 2K 78643K 3 0
memdesc 1 4K 4K 78643K 1 0
crypto data 1 1K 1K 78643K 1 0
NDP 4 0K 0K 78643K 4 0
temp 23 3969K 4033K 78643K 1687 0
kqueue 3 4K 4K 78643K 3 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 2 0 0 1 0 1 1 0 8 0
plcache 128 20 0 0 1 0 1 1 0 8 0
rtpcb 120 15 0 13 1 0 1 1 0 8 0
rtentry 112 23 0 1 1 0 1 1 0 8 0
unpcb 120 29 0 19 1 0 1 1 0 8 0
syncache 296 5 0 5 2 1 1 1 0 8 1
tcpqe 32 1 0 1 1 1 0 1 0 8 0
tcpcb 736 8 0 4 1 0 1 1 0 8 0
inpcb 304 29 0 22 1 0 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
pfstitem 24 9 0 2 1 0 1 1 0 8 0
pfstkey 112 9 0 2 1 0 1 1 0 8 0
pfstate 328 9 0 2 1 0 1 1 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 95 0 0 6 0 6 6 0 8 0
art_table 32 96 0 0 1 0 1 1 0 8 0
art_node 16 22 0 2 1 0 1 1 0 8 0
dirhash 1024 17 0 0 3 0 3 3 0 8 0
dino2pl 256 1398 0 16 87 0 87 87 0 8 0
ffsino 272 1398 0 16 93 0 93 93 0 8 0
nchpl 144 1572 0 33 59 1 58 58 0 8 0
uvmvnodes 72 1408 0 0 26 0 26 26 0 8 0
vnodes 224 1408 0 0 83 0 83 83 0 8 0
namei 1024 3781 0 3781 2 1 1 1 0 8 1
percpumem 16 31 0 0 1 0 1 1 0 8 0
scxspl 216 3637 0 3637 10 9 1 8 0 8 1
plimitpl 152 14 0 8 1 0 1 1 0 8 0
sigapl 424 221 0 192 4 0 4 4 0 8 0
knotepl 112 6 0 1 1 0 1 1 0 8 0
kqueuepl 168 2 0 0 1 0 1 1 0 8 0
pipepl 336 64 0 60 2 1 1 1 0 8 0
fdescpl 496 205 0 192 3 0 3 3 0 8 0
filepl 152 959 0 909 2 0 2 2 0 8 0
lockfpl 104 5 0 4 1 0 1 1 0 8 0
lockfspl 48 3 0 2 1 0 1 1 0 8 0
sessionpl 144 18 0 9 1 0 1 1 0 8 0
pgrppl 48 18 0 9 1 0 1 1 0 8 0
ucredpl 96 62 0 53 1 0 1 1 0 8 0
zombiepl 144 192 0 192 2 1 1 1 0 8 1
processpl 1080 221 0 192 3 0 3 3 0 8 0
procpl 672 223 0 192 3 0 3 3 0 8 0
sockpl 432 73 0 54 4 1 3 3 0 8 0
mcl4k 4096 3 0 0 1 0 1 1 0 8 0
mcl2k 2048 64 0 0 8 0 8 8 0 8 0
mtagpl 96 1 0 0 1 0 1 1 0 8 0
mbufpl 256 95 0 0 5 0 5 5 0 8 0
bufpl 280 2005 0 112 136 0 136 136 0 8 0
anonpl 24 19974 0 18705 11 2 9 10 0 186 1
amapchunkpl 152 531 0 490 3 1 2 3 0 158 0
amappl16 200 77 0 72 1 0 1 1 0 8 0
amappl15 192 1 0 0 1 0 1 1 0 8 0
amappl14 184 22 0 19 1 0 1 1 0 8 0
amappl13 176 14 0 13 2 1 1 1 0 8 0
amappl12 168 4 0 4 2 1 1 1 0 8 1
amappl11 160 51 0 36 1 0 1 1 0 8 0
amappl10 152 12 0 10 1 0 1 1 0 8 0
amappl9 144 234 0 234 2 1 1 1 0 8 1
amappl8 136 63 0 61 1 0 1 1 0 8 0
amappl7 128 209 0 208 1 0 1 1 0 8 0
amappl6 120 57 0 49 1 0 1 1 0 8 0
amappl5 112 355 0 340 1 0 1 1 0 8 0
amappl4 104 275 0 252 1 0 1 1 0 8 0
amappl3 96 108 0 100 1 0 1 1 0 8 0
amappl2 88 840 0 779 2 0 2 2 0 8 0
amappl1 80 14214 0 13776 17 6 11 17 0 8 0
amappl 88 405 0 383 1 0 1 1 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 64 2 0 0 1 0 1 1 0 8 0
uaddrrnd 24 205 0 192 1 0 1 1 0 8 0
uaddrbest 32 2 0 0 1 0 1 1 0 8 0
uaddr 24 205 0 192 1 0 1 1 0 8 0
vmmpekpl 168 5587 0 5569 1 0 1 1 0 8 0
vmmpepl 168 30085 0 29205 51 12 39 48 0 357 0
vmsppl 368 204 0 192 2 0 2 2 0 8 0
rwobjpl 56 7705 0 7129 14 5 9 13 0 8 0
pdppl 4096 417 0 384 51 18 33 39 0 8 0
pvpl 32 80770 0 77718 34 6 28 28 0 265 0
pmappl 232 204 0 192 1 0 1 1 0 8 0
extentpl 40 58 0 40 1 0 1 1 0 8 0
phpool 112 267 0 23 8 0 8 8 0 8 0
ddb{1}> machine ddbcpu 0
Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp
x86_ipi_db(ffffffff82738ff0) 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
__mp_lock(ffffffff828cc890) at __mp_lock+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline]
__mp_lock(ffffffff828cc890) at __mp_lock+0x129 sys/kern/kern_lock.c:147
softintr_dispatch(0) at softintr_dispatch+0x4e sys/arch/amd64/amd64/softintr.c:90
Xsoftclock() at Xsoftclock+0x1f
end of kernel
end trace frame: 0x7f7fffff4f40, count: 9
ddb{0}> trace
x86_ipi_db(ffffffff82738ff0) 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
__mp_lock(ffffffff828cc890) at __mp_lock+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline]
__mp_lock(ffffffff828cc890) at __mp_lock+0x129 sys/kern/kern_lock.c:147
softintr_dispatch(0) at softintr_dispatch+0x4e sys/arch/amd64/amd64/softintr.c:90
Xsoftclock() at Xsoftclock+0x1f
end of kernel
end trace frame: 0x7f7fffff4f40, count: -6
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(ffffffff823c3c11) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242d86c,ffffffff82425328,4f4,ffffffff823ad335) at __assert+0x2b sys/kern/subr_prf.c:162
kqueue_terminate(0,fffffd806e92ebd0) at kqueue_terminate+0x152 sys/kern/kern_event.c:1268
kqueue_close(fffffd807bacfa18,ffff8000ffff6010) at kqueue_close+0x40 sys/kern/kern_event.c:1286
fdrop(fffffd807bacfa18,ffff8000ffff6010) at fdrop+0xc2 sys/kern/kern_descrip.c:1279
closef(fffffd807bacfa18,ffff8000ffff6010) at closef+0x11c sys/kern/kern_descrip.c:1263
finishdup(ffff8000ffff6010,fffffd807bacf1c8,4,3,ffff800021263ac0,2) at finishdup+0x321 sys/kern/kern_descrip.c:691
dodup3(ffff8000ffff6010,4,3,0,ffff800021263ac0) at dodup3+0x5cf sys/kern/kern_descrip.c:397
syscall(ffff800021263b40) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800021263b40) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x553cbc72400, count: 4
ddb{1}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff823c3c11) at panic+0x15e sys/kern/subr_prf.c:218
__assert(ffffffff8242d86c,ffffffff82425328,4f4,ffffffff823ad335) at __assert+0x2b sys/kern/subr_prf.c:162
kqueue_terminate(0,fffffd806e92ebd0) at kqueue_terminate+0x152 sys/kern/kern_event.c:1268
kqueue_close(fffffd807bacfa18,ffff8000ffff6010) at kqueue_close+0x40 sys/kern/kern_event.c:1286
fdrop(fffffd807bacfa18,ffff8000ffff6010) at fdrop+0xc2 sys/kern/kern_descrip.c:1279
closef(fffffd807bacfa18,ffff8000ffff6010) at closef+0x11c sys/kern/kern_descrip.c:1263
finishdup(ffff8000ffff6010,fffffd807bacf1c8,4,3,ffff800021263ac0,2) at finishdup+0x321 sys/kern/kern_descrip.c:691
dodup3(ffff8000ffff6010,4,3,0,ffff800021263ac0) at dodup3+0x5cf sys/kern/kern_descrip.c:397
syscall(ffff800021263b40) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800021263b40) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x553cbc72400, count: -11
ddb{1}>