uvm_fault: tun_init

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syzbot

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Jan 16, 2020, 2:07:13 AM1/16/20
to syzkaller-o...@googlegroups.com
Hello,

syzbot found the following crash on:

HEAD commit: 2a9551c7 Add multiple altname fields and test for differen..
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=11fd7156e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=bf87b6915a88cd0d
dashboard link: https://syzkaller.appspot.com/bug?extid=b4b110f4519c70a04043

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+b4b110...@syzkaller.appspotmail.com

uvm_fault(0xffffffff8253e168, 0xffff800000000001, 0, 1) -> e
kernel: page fault trap, code=0
Stopped at tun_init+0x98: movzbl 0x1(%rbx),%r13d
ddb{1}>
ddb{1}> set $lines = 0
ddb{1}> set $maxwidth = 0
ddb{1}> show panic
kernel page fault
uvm_fault(0xffffffff8253e168, 0xffff800000000001, 0, 1) -> e
tun_init(ffff800000a1d800) at tun_init+0x98 sys/net/if_tun.c:486
end trace frame: 0xffff800021f91970, count: 0
ddb{1}> trace
tun_init(ffff800000a1d800) at tun_init+0x98 sys/net/if_tun.c:486
tun_ioctl(ffff800000a1d800,8020690c,ffff800000a57800) at tun_ioctl+0x100
in_ifinit(ffff800000a1d800,ffff800000a57800,ffff800000a57858,0) at
in_ifinit+0x18b sys/netinet/in.c:679
in_ioctl_change_ifaddr(8040691a,ffff800021f91bf0,ffff800000a1d800,1) at
in_ioctl_change_ifaddr+0x68c sys/netinet/in.c:519
in_ioctl(8040691a,ffff800021f91bf0,ffff800000a1d800,1) at in_ioctl+0x2fb
sys/netinet/in.c:246
ifioctl(fffffd806f669190,8040691a,ffff800021f91bf0,ffff800020ac8780) at
ifioctl+0xe70 sys/net/if.c:2291
sys_ioctl(ffff800020ac8780,ffff800021f91d08,ffff800021f91d50) at
sys_ioctl+0x498
syscall(ffff800021f91dd0) at syscall+0x4a4 mi_syscall
sys/sys/syscall_mi.h:92 [inline]
syscall(ffff800021f91dd0) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0xca5ed89a8c0, count: -9
ddb{1}> show registers
rdi 0xffffffff8102d9b5 tun_init+0x95
rsi 0x144
rbp 0xffff800021f91910
rbx 0xffff800000000000
rdx 0x145
rcx 0xffff800022d9a000
rax 0xffff800022d9a000
r8 0xffffffff8102c7ee tun_ioctl+0x3e
r9 0x7
r10 0x8020697f __kernel_virt_to_phys+0x20697f
r11 0x50e3c7a8b61a5aa
r12 0xffff800000a57c40
r13 0x60080fe __kernel_end_phys+0x38080fe
r14 0x90b
r15 0xffff800000a58000
rip 0xffffffff8102d9b8 tun_init+0x98
cs 0x8
rflags 0x10246 __ALIGN_SIZE+0xf246
rsp 0xffff800021f918b0
ss 0x10
tun_init+0x98: movzbl 0x1(%rbx),%r13d
ddb{1}> show proc
PROC (syz-executor.1) pid=233212 stat=onproc
flags process=0 proc=4000000<THREAD>
pri=60, usrpri=60, nice=20
forw=0xffffffffffffffff, list=0xffff800020ac8290,0xffffffff82640d40
process=0xffff800020af4700 user=0xffff800021f8c000,
vmspace=0xfffffd807f000000
estcpu=36, cpticks=1, pctcpu=0.0
user=0, sys=1, intr=0
ddb{1}> ps
PID TID PPID UID S FLAGS WAIT COMMAND
8605 2731 99561 0 2 0 syz-executor.1
* 8605 233212 99561 0 7 0x4000000 syz-executor.1
57054 63168 0 0 3 0x14200 bored sosplice
99561 160830 35107 0 3 0x82 nanosleep syz-executor.1
62750 54827 35107 0 3 0x2 biowait syz-executor.0
35107 299272 85425 0 3 0x82 thrsleep syz-fuzzer
35107 88013 85425 0 3 0x4000082 nanosleep syz-fuzzer
35107 311983 85425 0 3 0x4000082 thrsleep syz-fuzzer
35107 105710 85425 0 3 0x4000082 thrsleep syz-fuzzer
35107 110710 85425 0 3 0x4000082 thrsleep syz-fuzzer
35107 377430 85425 0 3 0x4000082 thrsleep syz-fuzzer
35107 1775 85425 0 7 0x4000002 syz-fuzzer
35107 224617 85425 0 3 0x4000082 thrsleep syz-fuzzer
35107 523189 85425 0 3 0x4000082 thrsleep syz-fuzzer
35107 263864 85425 0 3 0x4000082 nanosleep syz-fuzzer
85425 23216 80698 0 3 0x10008a pause ksh
80698 220840 2090 0 3 0x92 select sshd
7279 4469 1 0 3 0x100083 ttyin getty
2090 46865 1 0 3 0x80 select sshd
34512 181500 13638 74 3 0x100092 bpf pflogd
13638 103853 1 0 3 0x80 netio pflogd
86754 47949 7734 73 3 0x100090 kqread syslogd
7734 70797 1 0 3 0x100082 netio syslogd
49670 359924 0 0 3 0x14200 pgzero zerothread
1323 458848 0 0 3 0x14200 aiodoned aiodoned
79609 474001 0 0 3 0x14200 syncer update
44792 501099 0 0 3 0x14200 cleaner cleaner
15413 112962 0 0 3 0x14200 reaper reaper
12834 237561 0 0 3 0x14200 pgdaemon pagedaemon
15766 475676 0 0 3 0x14200 bored crynlk
87267 281969 0 0 3 0x14200 bored crypto
37768 311018 0 0 3 0x40014200 acpi0 acpi0
91855 445260 0 0 3 0x40014200 idle1
90369 472019 0 0 3 0x14200 bored softnet
29332 298028 0 0 3 0x14200 bored systqmp
5603 34177 0 0 3 0x14200 bored systq
11949 334897 0 0 3 0x40014200 bored softclock
70527 420485 0 0 3 0x40014200 idle0
49184 179588 0 0 3 0x14200 bored smr
1 213738 0 0 3 0x82 wait init
0 0 -1 0 3 0x10200 scheduler swapper
ddb{1}> show all locks
Process 8605 (syz-executor.1) thread 0xffff800020ac8780 (233212)
exclusive rwlock netlock r = 0 (0xffffffff824f5708)
#0 witness_lock+0x52e sys/kern/subr_witness.c:1163
#1 in_ioctl_change_ifaddr+0x91
#2 in_ioctl+0x2fb sys/netinet/in.c:246
#3 ifioctl+0xe70 sys/net/if.c:2291
#4 sys_ioctl+0x498
#5 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline]
#5 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
#6 Xsyscall+0x128
exclusive kernel_lock &kernel_lock r = 1 (0xffffffff82663c50)
#0 witness_lock+0x52e sys/kern/subr_witness.c:1163
#1 syscall+0x400 mi_syscall sys/sys/syscall_mi.h:83 [inline]
#1 syscall+0x400 sys/arch/amd64/amd64/trap.c:570
#2 Xsyscall+0x128
Process 62750 (syz-executor.0) thread 0xffff800020ac9160 (54827)
exclusive rrwlock inode r = 0 (0xfffffd8065fd5e70)
#0 witness_lock+0x52e sys/kern/subr_witness.c:1163
#1 rw_enter+0x453 sys/kern/kern_rwlock.c:309
#2 rrw_enter+0x88 sys/kern/kern_rwlock.c:453
#3 VOP_LOCK+0xf9 sys/kern/vfs_vops.c:615
#4 vn_lock+0x81 sys/kern/vfs_vnops.c:571
#5 vget+0x1c8 sys/kern/vfs_subr.c:671
#6 ufs_ihashget+0x141 sys/ufs/ufs/ufs_ihash.c:119
#7 ffs_vget+0x74 sys/ufs/ffs/ffs_vfsops.c:1323
#8 ufs_lookup+0x14b7 sys/ufs/ufs/ufs_lookup.c:487
#9 VOP_LOOKUP+0x5b sys/kern/vfs_vops.c:91
#10 vfs_lookup+0x7a6 sys/kern/vfs_lookup.c:568
#11 namei+0x63c sys/kern/vfs_lookup.c:249
#12 dounlinkat+0x99 sys/kern/vfs_syscalls.c:1776
#13 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline]
#13 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
#14 Xsyscall+0x128
exclusive rrwlock inode r = 0 (0xfffffd806acbf4d8)
#0 witness_lock+0x52e sys/kern/subr_witness.c:1163
#1 rw_enter+0x453 sys/kern/kern_rwlock.c:309
#2 rrw_enter+0x88 sys/kern/kern_rwlock.c:453
#3 VOP_LOCK+0xf9 sys/kern/vfs_vops.c:615
#4 vn_lock+0x81 sys/kern/vfs_vnops.c:571
#5 vfs_lookup+0xe6 sys/kern/vfs_lookup.c:419
#6 namei+0x63c sys/kern/vfs_lookup.c:249
#7 dounlinkat+0x99 sys/kern/vfs_syscalls.c:1776
#8 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline]
#8 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
#9 Xsyscall+0x128
ddb{1}> show malloc
Type InUse MemUse HighUse Limit Requests Type Lim
devbuf 9502 6412K 7636K 78643K 11027 0
pcb 13 8K 8K 78643K 41 0
rtable 101 5K 5K 78643K 252 0
ifaddr 68 13K 13K 78643K 90 0
counters 39 33K 33K 78643K 39 0
ioctlops 0 0K 4K 78643K 1469 0
iov 0 0K 16K 78643K 16 0
mount 1 1K 1K 78643K 1 0
vnodes 1232 77K 77K 78643K 1332 0
UFS quota 1 32K 32K 78643K 1 0
UFS mount 5 36K 36K 78643K 5 0
shm 2 1K 5K 78643K 4 0
VM map 2 1K 1K 78643K 2 0
sem 12 0K 0K 78643K 28 0
dirhash 12 2K 2K 78643K 12 0
ACPI 1809 196K 290K 78643K 12766 0
file desc 5 13K 25K 78643K 123 0
sigio 0 0K 0K 78643K 2 0
proc 56 51K 95K 78643K 452 0
subproc 32 2K 2K 78643K 34 0
NFS srvsock 1 0K 0K 78643K 1 0
NFS daemon 1 16K 16K 78643K 1 0
ip_moptions 0 0K 0K 78643K 4 0
in_multi 44 2K 2K 78643K 61 0
ether_multi 1 0K 0K 78643K 4 0
mrt 0 0K 0K 78643K 2 0
ISOFS mount 1 32K 32K 78643K 1 0
MSDOSFS mount 1 16K 16K 78643K 1 0
ttys 43 201K 201K 78643K 43 0
exec 0 0K 1K 78643K 218 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 102 21K 23K 78643K 1350 0
UVM aobj 12 2K 2K 78643K 12 0
memdesc 1 4K 4K 78643K 1 0
crypto data 1 1K 1K 78643K 1 0
ip6_options 0 0K 0K 78643K 13 0
NDP 11 0K 0K 78643K 19 0
temp 101 3015K 3083K 78643K 11012 0
kqueue 3 4K 24K 78643K 19 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 6 0 2 1 0 1 1 0
8 0
plcache 128 20 0 0 1 0 1 1 0
8 0
rtpcb 80 62 0 61 1 0 1 1 0
8 0
rtentry 112 50 0 11 2 0 2 2 0
8 0
unpcb 120 117 0 109 1 0 1 1 0
8 0
syncache 264 5 0 5 2 1 1 1 0
8 1
sackhl 24 1 0 1 1 0 1 1 0
8 1
tcpqe 32 241 0 241 1 1 0 1 0
8 0
tcpcb 544 46 0 41 1 0 1 1 0
8 0
inpcb 280 238 0 230 2 0 2 2 0
8 1
nd6 48 5 0 2 1 0 1 1 0
8 0
ppxss 1128 3 0 3 1 0 1 1 0
8 1
pffrag 232 8 0 8 1 0 1 1 0
482 1
pffrnode 88 8 0 8 1 0 1 1 0
8 1
pffrent 40 231 0 231 1 0 1 1 0
8 1
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 29 0 0 1 0 1 1 0
8 0
pfstkey 112 29 0 0 1 0 1 1 0
8 0
pfstate 328 29 0 0 3 0 3 3 0
8 0
pfrule 1360 21 0 16 2 1 1 2 0
8 0
art_heap8 4096 2 0 0 2 0 2 2 0
8 0
art_heap4 256 261 0 43 14 0 14 14 0
8 0
art_table 32 263 0 43 2 0 2 2 0
8 0
art_node 16 49 0 13 1 0 1 1 0
8 0
sysvmsgpl 40 6 0 2 1 0 1 1 0
8 0
semupl 112 3 0 3 1 0 1 1 0
8 1
semapl 112 26 0 16 1 0 1 1 0
8 0
shmpl 112 10 0 0 1 0 1 1 0
8 0
dirhash 1024 17 0 0 3 0 3 3 0
8 0
dino1pl 128 1554 0 145 46 0 46 46 0
8 0
ffsino 272 1554 0 145 95 0 95 95 0
8 0
nchpl 144 1938 0 318 61 0 61 61 0
8 0
uvmvnodes 72 1697 0 0 31 0 31 31 0
8 0
vnodes 208 1697 0 0 90 0 90 90 0
8 0
namei 1024 5192 0 5192 1 0 1 1 0
8 1
percpumem 16 30 0 0 1 0 1 1 0
8 0
scxspl 192 5576 0 5575 5 1 4 4 0
8 3
plimitpl 152 24 0 17 1 0 1 1 0
8 0
sigapl 432 322 0 309 3 0 3 3 0
8 1
futexpl 56 2267 0 2267 1 0 1 1 0
8 1
knotepl 112 72 0 53 1 0 1 1 0
8 0
kqueuepl 104 34 0 32 1 0 1 1 0
8 0
pipelkpl 48 103 0 93 1 0 1 1 0
8 0
pipepl 120 206 0 187 2 0 2 2 0
8 1
fdescpl 496 323 0 309 3 0 3 3 0
8 0
filepl 152 2022 0 1927 6 0 6 6 0
8 2
lockfpl 104 31 0 31 1 0 1 1 0
8 1
lockfspl 48 13 0 13 1 0 1 1 0
8 1
sessionpl 112 18 0 9 1 0 1 1 0
8 0
pgrppl 48 18 0 9 1 0 1 1 0
8 0
ucredpl 96 138 0 130 1 0 1 1 0
8 0
zombiepl 144 309 0 309 1 0 1 1 0
8 1
processpl 896 339 0 309 4 0 4 4 0
8 0
procpl 632 581 0 541 5 0 5 5 0
8 1
srpgc 64 2 0 2 1 0 1 1 0
8 1
sosppl 128 26 0 26 1 0 1 1 0
8 1
sockpl 400 433 0 416 4 0 4 4 0
8 2
mcl64k 65536 16 0 0 2 0 2 2 0
8 0
mcl16k 16384 1 0 0 1 0 1 1 0
8 0
mcl12k 12288 4 0 0 1 0 1 1 0
8 0
mcl9k 9216 3 0 0 1 0 1 1 0
8 0
mcl8k 8192 4 0 0 1 0 1 1 0
8 0
mcl4k 4096 4 0 0 1 0 1 1 0
8 0
mcl2k 2048 156 0 0 19 0 19 19 0
8 0
mtagpl 80 3 0 0 1 0 1 1 0
8 0
mbufpl 256 385 0 0 24 0 24 24 0
8 0
bufpl 280 6664 0 1340 381 0 381 381 0
8 0
anonpl 16 45277 0 30230 62 1 61 61 0
125 0
amapchunkpl 152 1819 0 1696 13 0 13 13 0
158 7
amappl16 192 1309 0 479 43 1 42 42 0
8 0
amappl15 184 63 0 59 1 0 1 1 0
8 0
amappl14 176 79 0 74 1 0 1 1 0
8 0
amappl13 168 2 0 2 2 2 0 1 0
8 0
amappl12 160 50 0 48 1 0 1 1 0
8 0
amappl11 152 54 0 46 1 0 1 1 0
8 0
amappl10 144 27 0 20 1 0 1 1 0
8 0
amappl9 136 591 0 588 1 0 1 1 0
8 0
amappl8 128 113 0 94 1 0 1 1 0
8 0
amappl7 120 102 0 91 1 0 1 1 0
8 0
amappl6 112 57 0 50 1 0 1 1 0
8 0
amappl5 104 196 0 185 1 0 1 1 0
8 0
amappl4 96 576 0 548 1 0 1 1 0
8 0
amappl3 88 125 0 115 1 0 1 1 0
8 0
amappl2 80 1661 0 1593 3 0 3 3 0
8 0
amappl1 72 17212 0 16799 26 15 11 20 0
8 1
amappl 80 832 0 794 1 0 1 1 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 11 0 0 1 0 1 1 0
8 0
uaddrrnd 24 323 0 309 1 0 1 1 0
8 0
uaddrbest 32 2 0 0 1 0 1 1 0
8 0
uaddr 24 323 0 309 1 0 1 1 0
8 0
vmmpekpl 168 6434 0 6399 2 0 2 2 0
8 0
vmmpepl 168 46929 0 45017 116 8 108 108 0 357
21
vmsppl 368 322 0 309 2 0 2 2 0
8 0
pdppl 4096 653 0 618 6 0 6 6 0
8 1
pvpl 32 157692 0 139568 148 0 148 148 0
265 1
pmappl 232 322 0 309 2 0 2 2 0
8 1
extentpl 40 46 0 29 1 0 1 1 0
8 0
phpool 112 180 0 3 6 0 6 6 0
8 0


---
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syzbot

unread,
Apr 15, 2020, 3:07:10 AM4/15/20
to syzkaller-o...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
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