login: panic: kernel diagnostic assertion "atomic_load_int(&fdp->fd_nuserevents) == 0" failed: file "/syzkaller/managers/setuid/kernel/sys/kern/kern_descrip.c", line 1219
Stopped at db_enter+0x25: addq $0x8,%rsp
TID PID UID PRFLAGS PFLAGS CPU COMMAND
34024 1900 32767 0x10 0x4000000 1 syz-executor
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff83454272) at panic+0x1e5 sys/kern/subr_prf.c:198
__assert(ffffffff8348ea27,ffffffff83466629,4c3,ffffffff83421815) at __assert+0x29 sys/kern/subr_prf.c:-1
fdfree(ffff80002a244a78) at fdfree+0x349
exit1(ffff80002a244a78,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215
sys_exit(ffff80002a244a78,ffff800038bc27d0,ffff800038bc2720) at sys_exit+0x1a sys/kern/kern_exit.c:-1
syscall(ffff800038bc27d0) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff800038bc27d0) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x75e6311587f0, count: 7
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 "atomic_load_int(&fdp->fd_nuserevents) == 0" failed: file "/syzkaller/managers/setuid/kernel/sys/kern/kern_descrip.c", line 1219
ddb{0}> trace
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff83454272) at panic+0x1e5 sys/kern/subr_prf.c:198
__assert(ffffffff8348ea27,ffffffff83466629,4c3,ffffffff83421815) at __assert+0x29 sys/kern/subr_prf.c:-1
fdfree(ffff80002a244a78) at fdfree+0x349
exit1(ffff80002a244a78,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215
sys_exit(ffff80002a244a78,ffff800038bc27d0,ffff800038bc2720) at sys_exit+0x1a sys/kern/kern_exit.c:-1
syscall(ffff800038bc27d0) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff800038bc27d0) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x75e6311587f0, count: -8
ddb{0}> show registers
rdi 0
rsi 0x1
rbp 0xffff800038bc2510
rbx 0xffffffff83965e07 cpu_info_full_primary+0x2e07
rdx 0
rcx 0xffff80002a244a78
rax 0xffffffff83964ff0 cpu_info_full_primary+0x1ff0
r8 0x101010101010101
r9 0x8080808080808080
r10 0xbd2cc9d48f5009b9
r11 0x89e403de6671ac8
r12 0xffffffff83965c08 cpu_info_full_primary+0x2c08
r13 0
r14 0
r15 0x1
rip 0xffffffff82993cb5 db_enter+0x25
cs 0x8
rflags 0x246
rsp 0xffff800038bc2500
ss 0x10
db_enter+0x25: addq $0x8,%rsp
ddb{0}> show proc
PROC (syz-executor) tid=61627 pid=89666 tcnt=0 stat=onproc
flags process=1018<EXITING,SUGID,SINGLEEXIT> proc=2000<WEXIT>
runpri=32, usrpri=76, slppri=32, nice=20
wchan=0x0, wmesg=, ps_single=0xffff80002a244a78 scnt=-1 ecnt=1
forw=0xffffffffffffffff, list=0xffff800035fa6a80,0xffff800035fa6d28
process=0xffff8000fffe79e0 user=0xffff800038bbd000, vmspace=0xfffffd806ca05018
estcpu=26, cpticks=15, pctcpu=0.11, user=0, sys=2, intr=0
ddb{0}> ps
PID TID PPID UID S FLAGS WAIT COMMAND
23295 39793 56004 32767 2 0x10 syz-executor
1900 317041 23932 32767 2 0x10 syz-executor
1900 91328 23932 32767 2 0x4000010 syz-executor
1900 34024 23932 32767 7 0x4000010 syz-executor
53679 19398 29422 32767 2 0xc90 syz-executor
53679 210168 29422 32767 3 0x4000090 kqsel syz-executor
53679 344516 29422 32767 3 0x4000090 fsleep syz-executor
23932 180607 35030 32767 2 0xc90 syz-executor
65018 381095 95564 32767 3 0x90 wait syz-executor
56004 290144 69331 32767 2 0xc90 syz-executor
71166 208240 92221 32767 2 0xc90 syz-executor
52515 20435 82858 32767 2 0x10 syz-executor
59234 103910 96989 32767 2 0xc90 syz-executor
29422 81464 62152 32767 2 0xc90 syz-executor
20429 245814 99785 32767 2 0xc90 syz-executor
35030 287931 16700 0 3 0x82 wait syz-executor
95564 77037 16700 0 3 0x82 wait syz-executor
92221 227081 16700 0 3 0x82 wait syz-executor
69331 256850 16700 0 3 0x82 wait syz-executor
62152 351503 16700 0 3 0x82 wait syz-executor
82858 273557 16700 0 3 0x82 wait syz-executor
96989 335877 16700 0 3 0x82 wait syz-executor
99785 291588 16700 0 3 0x82 wait syz-executor
16700 336427 57028 0 3 0x82 kqread syz-executor
57028 300251 28302 0 3 0x10008a sigsusp ksh
28302 78590 35787 0 3 0x98 kqread sshd-session
35787 488716 39369 0 3 0x92 kqread sshd-session
22399 118984 1 0 3 0x100083 ttyin getty
39369 215590 1 0 3 0x88 kqread sshd
40675 59277 67768 73 3 0x1100090 kqread syslogd
67768 448164 1 0 3 0x100082 sbwait syslogd
46926 364328 1 0 3 0x100080 kqread resolvd
97788 476484 76641 77 3 0x100092 kqread dhcpleased
73678 57066 76641 77 3 0x100092 kqread dhcpleased
76641 463514 1 0 3 0x80 kqread dhcpleased
2207 27935 0 0 3 0x14200 bored smr
28533 340206 0 0 3 0x14200 pgzero zerothread
71588 117448 0 0 3 0x14200 aiodoned aiodoned
39139 62294 0 0 3 0x14200 syncer update
24964 110066 0 0 3 0x14200 cleaner cleaner
36561 403912 0 0 2 0x14200 reaper
49928 212677 0 0 3 0x14200 pgdaemon pagedaemon
47721 156322 0 0 3 0x14200 bored viomb
76876 397696 0 0 3 0x40014200 acpi0 acpi0
19287 275505 0 0 3 0x40014200 idle1
63770 22433 0 0 3 0x14200 bored softnet1
72776 363499 0 0 3 0x14200 bored softnet0
83868 162496 0 0 3 0x14200 bored systqmp
68139 330154 0 0 3 0x14200 bored systq
71020 362194 0 0 3 0x14200 tmoslp softclockmp
19332 150074 0 0 3 0x40014200 tmoslp softclock
42806 62990 0 0 3 0x40014200 idle0
1 432629 0 0 3 0x82 wait init
0 0 -1 0 3 0x10200 scheduler swapper
ddb{0}> show all locks
Process 52515 (syz-executor) thread 0xffff80002a2442b0 (20435)
exclusive rrwlock inode r = 0 (0xfffffd806c86fea8)
#0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1 rw_do_enter_write+0x419 sys/kern/kern_rwlock.c:320
#2 rrw_enter+0xc6 sys/kern/kern_rwlock.c:621
#3 VOP_LOCK+0xbd sys/kern/vfs_vops.c:527
#4 vn_lock+0xa4 sys/kern/vfs_vnops.c:576
#5 vget+0x2a2 sys/kern/vfs_subr.c:686
#6 ufs_ihashget+0x185 sys/ufs/ufs/ufs_ihash.c:98
#7 ffs_vget+0x8c sys/ufs/ffs/ffs_vfsops.c:1203
#8 ufs_lookup+0x1a36 sys/ufs/ufs/ufs_lookup.c:478
#9 VOP_LOOKUP+0x6e sys/kern/vfs_vops.c:85
#10 vfs_lookup+0x98a sys/kern/vfs_lookup.c:567
#11 namei+0x7ca sys/kern/vfs_lookup.c:250
#12 dounlinkat+0xc1 sys/kern/vfs_syscalls.c:1887
#13 syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#13 syscall+0xb17 sys/arch/amd64/amd64/trap.c:783
#14 Xsyscall+0x128
exclusive rrwlock inode r = 0 (0xfffffd806c86f1f0)
#0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1 rw_do_enter_write+0x419 sys/kern/kern_rwlock.c:320
#2 rrw_enter+0xc6 sys/kern/kern_rwlock.c:621
#3 VOP_LOCK+0xbd sys/kern/vfs_vops.c:527
#4 vn_lock+0xa4 sys/kern/vfs_vnops.c:576
#5 vget+0x2a2 sys/kern/vfs_subr.c:686
#6 cache_lookup+0x351 sys/kern/vfs_cache.c:222
#7 ufs_lookup+0x1e3 sys/ufs/ufs/ufs_lookup.c:160
#8 VOP_LOOKUP+0x6e sys/kern/vfs_vops.c:85
#9 vfs_lookup+0x98a sys/kern/vfs_lookup.c:567
#10 namei+0x7ca sys/kern/vfs_lookup.c:250
#11 dounlinkat+0xc1 sys/kern/vfs_syscalls.c:1887
#12 syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
#12 syscall+0xb17 sys/arch/amd64/amd64/trap.c:783
#13 Xsyscall+0x128
ddb{0}> show malloc
Type InUse MemUse HighUse Limit Requests Type Lim
devbuf 11058 12019K 12034K 166960K 12149 0
pcb 17 12K 12K 166960K 17 0
rtable 239 6K 7K 166960K 356 0
pf 31 16K 16K 166960K 31 0
ifaddr 42 7K 7K 166960K 44 0
ifgroup 50 2K 2K 166960K 50 0
sysctl 1 1K 9K 166960K 5 0
counters 70 37K 37K 166960K 70 0
ioctlops 0 0K 2K 166960K 35 0
iov 0 0K 12K 166960K 5 0
mount 1 1K 1K 166960K 1 0
log 0 0K 0K 166960K 4 0
vnodes 1287 81K 81K 166960K 1454 0
UFS quota 1 32K 32K 166960K 1 0
UFS mount 5 36K 36K 166960K 5 0
shm 2 1K 9K 166960K 14 0
VM map 2 1K 1K 166960K 2 0
sem 11 0K 0K 166960K 13 0
dirhash 12 2K 2K 166960K 18 0
ACPI 1692 195K 286K 166960K 12470 0
file desc 24 89K 109K 166960K 298 0
sigio 0 0K 0K 166960K 4 0
proc 58 99K 131K 166960K 506 0
subproc 72 4K 4K 166960K 72 0
NFS srvsock 1 0K 0K 166960K 1 0
NFS daemon 1 16K 16K 166960K 1 0
ip_moptions 0 0K 0K 166960K 33 0
in_multi 99 7K 7K 166960K 104 0
ether_multi 1 0K 0K 166960K 1 0
mrt 0 0K 0K 166960K 12 0
ISOFS mount 1 32K 32K 166960K 1 0
MSDOSFS mount 1 16K 16K 166960K 1 0
ttys 91 413K 413K 166960K 91 0
exec 0 0K 1K 166960K 365 0
fusefs mount 1 32K 32K 166960K 1 0
tdb 3 0K 0K 166960K 3 0
VM swap 8 62K 64K 166960K 10 0
UVM amap 257 176K 190K 166960K 4313 0
UVM aobj 17 2K 2K 166960K 18 0
pinsyscall 46 92K 104K 166960K 1352 0
memdesc 1 4K 4K 166960K 1 0
crypto data 1 1K 1K 166960K 1 0
ip6_options 2 0K 0K 166960K 16 0
NDP 11 0K 2K 166960K 27 0
temp 47 9077K 9140K 166960K 4477 0
kqueue 14 20K 28K 166960K 60 0
SYN cache 2 16K 16K 166960K 2 0
ddb{0}> show all pools
Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
plcache 128 26 0 0 1 0 1 1 0 8 0
rtpcb 120 45 0 41 1 0 1 1 0 8 0
rtentry 176 113 0 2 6 0 6 6 0 8 0
unpcb 144 267 0 252 6 0 6 6 0 8 5
syncache 336 4 0 4 1 0 1 1 0 8 1
tcpcb 736 109 0 99 4 0 4 4 0 8 3
arp 136 19 0 0 1 0 1 1 0 8 0
ipq 40 1 0 0 1 0 1 1 0 8 0
ipqe 40 1 0 0 1 0 1 1 0 8 0
inpcb 328 225 0 210 4 0 4 4 0 8 2
nd6 152 25 0 1 1 0 1 1 0 8 0
kcovpl 48 8 0 0 1 0 1 1 0 8 0
art_heap8 4096 1 0 0 1 0 1 1 0 8 0
art_heap4 256 456 0 2 29 0 29 29 0 8 0
art_table 40 457 0 2 5 0 5 5 0 8 0
art_node 32 113 0 12 1 0 1 1 0 8 0
sysvmsgpl 40 42 0 2 1 0 1 1 0 8 0
semapl 112 11 0 2 1 0 1 1 0 8 0
shmpl 112 15 0 1 1 0 1 1 0 8 0
dirhash 1024 21 0 4 3 0 3 3 0 8 0
dino2pl 256 1884 0 422 93 0 93 93 0 8 0
ffsino 296 1884 0 422 114 0 114 114 0 8 0
nchpl 144 2306 0 615 64 0 64 64 0 8 0
vnodes 216 1965 0 0 110 0 110 110 0 8 0
namei 1024 7397 0 7397 1 0 1 1 0 8 1
percpumem 16 50 0 0 1 0 1 1 0 8 0
kstatmem 264 25 0 0 2 0 2 2 0 8 0
scxspl 216 9656 0 9656 5 1 4 4 1 8 4
plimitpl 152 93 0 69 2 0 2 2 0 8 1
sigapl 424 583 0 530 7 0 7 7 0 8 0
knotepl 120 149 0 0 5 0 5 5 0 8 0
kqueuepl 224 97 0 86 3 0 3 3 0 8 2
pipepl 344 128 0 99 3 0 3 3 0 8 0
fdescpl 528 567 0 530 3 0 3 3 0 8 0
filepl 160 3026 0 2767 16 0 16 16 0 8 4
lockfpl 104 205 0 203 1 0 1 1 0 8 0
lockfspl 48 28 0 26 1 0 1 1 0 8 0
sessionpl 144 33 0 16 1 0 1 1 0 8 0
pgrppl 48 41 0 16 1 0 1 1 0 8 0
ucredpl 104 654 0 635 1 0 1 1 0 8 0
zombiepl 144 534 0 530 1 0 1 1 0 8 0
processpl 1232 583 0 530 5 0 5 5 0 8 0
procpl 664 859 0 801 7 0 7 7 0 8 1
sosppl 176 1 0 1 1 0 1 1 0 8 1
sockpl 752 537 0 503 17 5 12 17 0 8 7
mcl64k 65536 2 0 0 1 0 1 1 0 8 0
mcl9k128 9344 1 0 0 1 0 1 1 0 8 0
mcl8k 8192 2 0 0 1 0 1 1 0 8 0
mcl4k 4096 130 0 0 17 0 17 17 0 8 0
mcl2k2 2112 1 0 0 1 0 1 1 0 8 0
mcl2k 2048 19 0 0 3 0 3 3 0 8 0
mtagpl 96 2 0 0 1 0 1 1 0 8 0
mbufpl 256 287 0 0 18 0 18 18 0 8 0
bufpl 280 3266 0 102 226 0 226 226 0 8 0
anonpl 32 7598 0 0 62 0 62 62 0 246 0
amapchunkpl 152 13199 0 12605 33 0 33 33 0 158 7
amappl16 200 2450 0 2202 15 1 14 14 0 8 0
amappl15 192 10 0 10 1 1 0 1 0 8 0
amappl14 184 396 0 395 1 0 1 1 0 8 0
amappl13 176 121 0 111 1 0 1 1 0 8 0
amappl12 168 809 0 773 2 0 2 2 0 8 0
amappl11 160 14 0 13 1 0 1 1 0 8 0
amappl10 152 59 0 49 1 0 1 1 0 8 0
amappl9 144 259 0 259 1 1 0 1 0 8 0
amappl8 136 116 0 115 1 0 1 1 0 8 0
amappl7 128 134 0 122 1 0 1 1 0 8 0
amappl6 120 173 0 172 1 0 1 1 0 8 0
amappl5 112 93 0 85 1 0 1 1 0 8 0
amappl4 104 250 0 235 1 0 1 1 0 8 0
amappl3 96 2424 0 2291 4 0 4 4 0 8 0
amappl2 88 483 0 431 2 0 2 2 0 8 0
amappl1 80 9554 0 8972 13 0 13 13 0 8 0
amappl 88 3625 0 3433 5 0 5 5 0 92 0
uvmvnodes 80 102 0 0 3 0 3 3 0 8 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 17 0 1 1 0 1 1 0 8 0
uaddrrnd 24 567 0 530 1 0 1 1 0 8 0
uaddrbest 32 2 0 0 1 0 1 1 0 8 0
uaddr 24 567 0 530 1 0 1 1 0 8 0
vmmpekpl 168 6012 0 5968 3 0 3 3 0 8 1
vmmpepl 168 43756 0 41471 104 0 104 104 0 357 1
vmsppl 488 566 0 530 6 0 6 6 0 8 1
rwobjpl 80 15280 0 14077 26 0 26 26 0 8 0
pdppl 4096 1141 0 1060 105 22 83 91 0 8 2
pvpl 32 14646 0 0 119 0 119 119 0 265 0
pmappl 256 566 0 530 3 0 3 3 0 8 0
extentpl 40 45 0 27 1 0 1 1 0 8 0
phpool 112 283 0 24 8 0 8 8 0 8 0
ddb{0}> machine ddbcpu 0
Invalid cpu 0
ddb{0}> trace
db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438
panic(ffffffff83454272) at panic+0x1e5 sys/kern/subr_prf.c:198
__assert(ffffffff8348ea27,ffffffff83466629,4c3,ffffffff83421815) at __assert+0x29 sys/kern/subr_prf.c:-1
fdfree(ffff80002a244a78) at fdfree+0x349
exit1(ffff80002a244a78,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215
sys_exit(ffff80002a244a78,ffff800038bc27d0,ffff800038bc2720) at sys_exit+0x1a sys/kern/kern_exit.c:-1
syscall(ffff800038bc27d0) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff800038bc27d0) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x75e6311587f0, count: -8
ddb{0}> machine ddbcpu 1
Stopped at x86_ipi_db+0x27: addq $0x8,%rsp
x86_ipi_db(ffff8000299adff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394
x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27
__mp_lock(ffffffff839d8c00) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:142 [inline]
__mp_lock(ffffffff839d8c00) at __mp_lock+0x192 sys/kern/kern_lock.c:173
sysctl_file(ffff80003c456918,4,200000000100,ffff80003c456948,ffff80002a244d10) at sysctl_file+0x2d20 sys/kern/kern_sysctl.c:1796
kern_sysctl(ffff80003c456914,5,200000000100,ffff80003c456948,0,37,34ae766d54b8d011) at kern_sysctl+0x139 sys/kern/kern_sysctl.c:736
sys_sysctl(ffff80002a244d10,ffff80003c456a80,ffff80003c4569d0) at sys_sysctl+0x3e5 sys/kern/kern_sysctl.c:-1
syscall(ffff80003c456a80) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80003c456a80) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x43615c0ea00, count: 6
ddb{1}> trace
x86_ipi_db(ffff8000299adff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394
x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27
__mp_lock(ffffffff839d8c00) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:142 [inline]
__mp_lock(ffffffff839d8c00) at __mp_lock+0x192 sys/kern/kern_lock.c:173
sysctl_file(ffff80003c456918,4,200000000100,ffff80003c456948,ffff80002a244d10) at sysctl_file+0x2d20 sys/kern/kern_sysctl.c:1796
kern_sysctl(ffff80003c456914,5,200000000100,ffff80003c456948,0,37,34ae766d54b8d011) at kern_sysctl+0x139 sys/kern/kern_sysctl.c:736
sys_sysctl(ffff80002a244d10,ffff80003c456a80,ffff80003c4569d0) at sys_sysctl+0x3e5 sys/kern/kern_sysctl.c:-1
syscall(ffff80003c456a80) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline]
syscall(ffff80003c456a80) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x43615c0ea00, count: -9