uvm_fault: pmap_page_remove (2)

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syzbot

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Feb 13, 2020, 4:44:20 PM2/13/20
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Hello,

syzbot found the following crash on:

HEAD commit: f1dacf25 No need for "high performance" macros. While here..
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=156c3f85e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=fe55924c11e64b0a
dashboard link: https://syzkaller.appspot.com/bug?extid=106743ca17cc4202d333

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+106743...@syzkaller.appspotmail.com

uvm_fault(0xffffffff8255d208, 0x7fbfbfffffa0, 0, 2) -> e
kernel: page fault trap, code=0
Stopped at pmap_page_remove+0x33d: xchgq %rax,0(%r12,%rcx,1)
ddb>
ddb> set $lines = 0
ddb> set $maxwidth = 0
ddb> show panic
kernel page fault
uvm_fault(0xffffffff8255d208, 0x7fbfbfffffa0, 0, 2) -> e
pmap_page_remove(fffffd8005aa2b00) at pmap_page_remove+0x33d _atomic_swap_64 machine/atomic.h:117 [inline]
pmap_page_remove(fffffd8005aa2b00) at pmap_page_remove+0x33d sys/arch/amd64/amd64/pmap.c:1946
end trace frame: 0xffff80001d33c330, count: 0
ddb> trace
pmap_page_remove(fffffd8005aa2b00) at pmap_page_remove+0x33d _atomic_swap_64 machine/atomic.h:117 [inline]
pmap_page_remove(fffffd8005aa2b00) at pmap_page_remove+0x33d sys/arch/amd64/amd64/pmap.c:1946
uvm_anfree_list(fffffd8058dafb80,ffff80001d33c350) at uvm_anfree_list+0x4e sys/uvm/uvm_anon.c:104
amap_wipeout(fffffd8067ae8378) at amap_wipeout+0x171 sys/uvm/uvm_amap.c:461
uvm_unmap_detach(ffff80001d33c410,1) at uvm_unmap_detach+0x163 sys/uvm/uvm_map.c:1582
uvm_map_teardown(fffffd80561e8aa8) at uvm_map_teardown+0x22c sys/uvm/uvm_map.c:2757
uvmspace_free(fffffd80561e8aa8) at uvmspace_free+0x86 sys/uvm/uvm_map.c:3611
uvm_exit(ffff8000ffffb510) at uvm_exit+0x29 sys/uvm/uvm_glue.c:297
reaper(ffff80001d2f2110) at reaper+0x15c sys/kern/kern_exit.c:443
end trace frame: 0x0, count: -8
ddb> show registers
rdi 0
rsi 0
rbp 0xffff80001d33c2e0
rbx 0
rdx 0x100
rcx 0x7f8000000000
rax 0
r8 0
r9 0x7
r10 0xcd5f47c5e1256b5a
r11 0x83a794d8ee6bf23f
r12 0x3fbfffffa0
r13 0xfffffd805dc28d88
r14 0x800000006c3b6000
r15 0xfffffd8005aa2980
rip 0xffffffff814bf9dd pmap_page_remove+0x33d
cs 0x8
rflags 0x10246 __ALIGN_SIZE+0xf246
rsp 0xffff80001d33c250
ss 0x10
pmap_page_remove+0x33d: xchgq %rax,0(%r12,%rcx,1)
ddb> show proc
PROC (reaper) pid=67210 stat=onproc
flags process=14000<NOZOMBIE,SYSTEM> proc=200<SYSTEM>
pri=86, usrpri=86, nice=20
forw=0xffffffffffffffff, list=0xffff80001d2f1c30,0xffff80001d2f2d50
process=0xffff8000ffffce08 user=0xffff80001d337000, vmspace=0xffffffff8255d208
estcpu=36, cpticks=82, pctcpu=19.45
user=0, sys=2, intr=0
ddb> ps
PID TID PPID UID S FLAGS WAIT COMMAND
24315 302799 72449 0 3 0x10008a pause sh
197 148869 70620 0 3 0x10008a pause sh
72449 189913 97255 0 3 0x82 wait syz-executor.1
70620 449482 97255 0 3 0x82 wait syz-executor.0
79316 183404 0 0 3 0x14200 acct acct
10432 446358 0 0 3 0x14200 bored sosplice
14756 68161 1 0 3 0x100083 ttyin getty
97255 218670 82334 0 3 0x82 thrsleep syz-fuzzer
97255 97199 82334 0 3 0x4000082 nanosleep syz-fuzzer
97255 8429 82334 0 3 0x4000082 thrsleep syz-fuzzer
97255 455328 82334 0 3 0x4000082 thrsleep syz-fuzzer
97255 145713 82334 0 3 0x4000082 thrsleep syz-fuzzer
97255 470922 82334 0 3 0x4000082 thrsleep syz-fuzzer
97255 196366 82334 0 3 0x4000082 thrsleep syz-fuzzer
97255 233567 82334 0 3 0x4000082 kqread syz-fuzzer
97255 76854 82334 0 3 0x4000082 thrsleep syz-fuzzer
82334 297644 98350 0 3 0x10008a pause ksh
98350 191580 28549 0 3 0x92 select sshd
28549 229905 1 0 3 0x80 select sshd
86615 137735 63668 73 2 0x100010 syslogd
63668 352470 1 0 3 0x100082 netio syslogd
77980 5605 1 77 3 0x100090 poll dhclient
84812 291941 1 0 3 0x80 poll dhclient
49834 189419 0 0 2 0x14200 zerothread
84107 93876 0 0 3 0x14200 aiodoned aiodoned
39874 126646 0 0 3 0x14200 syncer update
25538 490703 0 0 3 0x14200 cleaner cleaner
* 93 67210 0 0 7 0x14200 reaper
65222 396231 0 0 3 0x14200 pgdaemon pagedaemon
23959 166909 0 0 3 0x14200 bored crynlk
56804 443321 0 0 3 0x14200 bored crypto
90449 234454 0 0 3 0x40014200 acpi0 acpi0
18184 503832 0 0 2 0x14200 softnet
66867 302619 0 0 3 0x14200 bored systqmp
96438 213219 0 0 3 0x14200 bored systq
59714 52494 0 0 3 0x40014200 bored softclock
66392 162720 0 0 3 0x40014200 idle0
53077 494509 0 0 3 0x14200 bored smr
1 305082 0 0 2 0x82 init
0 0 -1 0 3 0x10200 scheduler swapper
ddb> show all locks
No such command
ddb> show malloc
Type InUse MemUse HighUse Limit Requests Type Lim
devbuf 9496 6349K 7522K 78643K 11430 0
pcb 13 8K 8K 78643K 67 0
rtable 74 4K 5K 78643K 381 0
ifaddr 57 11K 14K 78643K 138 0
counters 19 16K 16K 78643K 30 0
ioctlops 0 0K 2K 78643K 32 0
iov 0 0K 12K 78643K 59 0
mount 1 1K 1K 78643K 1 0
vnodes 1229 77K 77K 78643K 1595 0
UFS quota 1 32K 32K 78643K 1 0
UFS mount 5 36K 36K 78643K 5 0
shm 2 1K 5K 78643K 22 0
VM map 2 0K 0K 78643K 2 0
sem 12 0K 0K 78643K 38 0
dirhash 12 2K 2K 78643K 12 0
ACPI 1794 195K 288K 78643K 12646 0
file desc 6 17K 25K 78643K 333 0
sigio 0 0K 0K 78643K 54 0
proc 49 38K 63K 78643K 519 0
subproc 34 2K 2K 78643K 102 0
NFS srvsock 1 0K 0K 78643K 1 0
NFS daemon 1 16K 16K 78643K 1 0
ip_moptions 0 0K 0K 78643K 19 0
in_multi 11 0K 2K 78643K 85 0
ether_multi 1 0K 0K 78643K 9 0
mrt 0 0K 0K 78643K 3 0
ISOFS mount 1 32K 32K 78643K 1 0
MSDOSFS mount 1 16K 16K 78643K 1 0
ttys 55 254K 254K 78643K 55 0
exec 0 0K 1K 78643K 236 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 131 79K 89K 78643K 1674 0
UVM aobj 17 2K 2K 78643K 70 0
memdesc 1 4K 4K 78643K 1 0
crypto data 1 1K 1K 78643K 1 0
ip6_options 0 0K 0K 78643K 118 0
NDP 11 0K 0K 78643K 32 0
temp 126 3018K 3090K 78643K 5679 0
kqueue 3 4K 20K 78643K 25 0
SYN cache 2 16K 16K 78643K 2 0
ddb> show all pools
Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
arp 64 12 0 10 1 0 1 1 0 8 0
rtpcb 80 37 0 35 1 0 1 1 0 8 0
rtentry 112 79 0 55 2 0 2 2 0 8 0
unpcb 120 425 0 417 2 1 1 2 0 8 0
syncache 264 9 0 9 3 3 0 1 0 8 0
tcpcb 544 227 0 223 1 0 1 1 0 8 0
ipq 40 2 0 2 1 1 0 1 0 8 0
ipqe 40 6 0 6 1 1 0 1 0 8 0
inpcb 280 450 0 443 3 2 1 2 0 8 0
rttmr 72 1 0 1 1 1 0 1 0 8 0
nd6 48 11 0 11 1 1 0 1 0 8 0
pkpcb 40 2 0 2 1 1 0 1 0 8 0
ppxss 1128 1 0 1 1 1 0 1 0 8 0
art_heap8 4096 1 0 0 1 0 1 1 0 8 0
art_heap4 256 411 0 289 17 8 9 14 0 8 0
art_table 32 412 0 289 2 0 2 2 0 8 0
art_node 16 78 0 56 1 0 1 1 0 8 0
sysvmsgpl 40 13 0 9 1 0 1 1 0 8 0
semupl 112 3 0 3 1 1 0 1 0 8 0
semapl 112 32 0 22 1 0 1 1 0 8 0
shmpl 112 68 0 53 1 0 1 1 0 8 0
dirhash 1024 17 0 0 3 0 3 3 0 8 0
dino1pl 128 1836 0 436 46 0 46 46 0 8 0
ffsino 240 1836 0 436 83 0 83 83 0 8 0
nchpl 144 2608 0 1016 60 0 60 60 0 8 0
uvmvnodes 72 2198 0 0 40 0 40 40 0 8 0
vnodes 208 2198 0 0 116 0 116 116 0 8 0
namei 1024 7577 0 7577 2 2 0 1 0 8 0
vcpupl 1984 5 0 0 1 0 1 1 0 8 0
vmpool 528 5 0 0 1 0 1 1 0 8 0
scxspl 192 8049 0 8049 1 0 1 1 0 8 1
plimitpl 152 38 0 29 1 0 1 1 0 8 0
sigapl 432 493 0 479 2 0 2 2 0 8 0
futexpl 56 8309 0 8309 1 1 0 1 0 8 0
knotepl 112 139 0 116 1 0 1 1 0 8 0
kqueuepl 104 68 0 66 1 0 1 1 0 8 0
pipelkpl 16 159 0 149 1 0 1 1 0 8 0
pipepl 120 318 0 299 2 1 1 2 0 8 0
fdescpl 432 494 0 479 2 0 2 2 0 8 0
filepl 120 3898 0 3803 6 3 3 5 0 8 0
lockfpl 104 105 0 104 1 0 1 1 0 8 0
lockfspl 48 34 0 33 1 0 1 1 0 8 0
sessionpl 112 22 0 10 1 0 1 1 0 8 0
pgrppl 48 24 0 12 1 0 1 1 0 8 0
ucredpl 96 446 0 439 1 0 1 1 0 8 0
zombiepl 144 479 0 475 2 1 1 1 0 8 0
processpl 896 510 0 475 4 0 4 4 0 8 0
procpl 624 858 0 815 4 0 4 4 0 8 0
sosppl 128 8 0 8 1 1 0 1 0 8 0
sockpl 400 924 0 907 5 3 2 5 0 8 0
mcl64k 65536 34 0 34 2 2 0 2 0 8 0
mcl16k 16384 1 0 1 1 1 0 1 0 8 0
mcl12k 12288 7 0 7 1 1 0 1 0 8 0
mcl9k 9216 3 0 3 1 1 0 1 0 8 0
mcl8k 8192 14 0 14 1 1 0 1 0 8 0
mcl4k 4096 56 0 56 2 2 0 1 0 8 0
mcl2k2 2112 1 0 1 1 1 0 1 0 8 0
mcl2k 2048 65688 0 65651 10 5 5 10 0 8 0
mtagpl 80 59 0 59 2 2 0 1 0 8 0
mbufpl 256 106861 0 106813 32 27 5 32 0 8 0
bufpl 280 6205 0 797 387 0 387 387 0 8 0
anonpl 16 64066 0 51557 81 1 80 80 0 107 12
amapchunkpl 152 2845 0 2685 21 3 18 20 0 158 10
amappl16 192 2154 0 1282 45 0 45 45 0 8 0
amappl15 184 57 0 52 1 0 1 1 0 8 0
amappl14 176 41 0 36 1 0 1 1 0 8 0
amappl13 168 1 0 0 1 0 1 1 0 8 0
amappl12 160 12 0 11 3 2 1 1 0 8 0
amappl11 152 195 0 184 1 0 1 1 0 8 0
amappl10 144 118 0 114 1 0 1 1 0 8 0
amappl9 136 576 0 571 1 0 1 1 0 8 0
amappl8 128 127 0 105 1 0 1 1 0 8 0
amappl7 120 203 0 188 1 0 1 1 0 8 0
amappl6 112 198 0 193 1 0 1 1 0 8 0
amappl5 104 190 0 178 1 0 1 1 0 8 0
amappl4 96 713 0 684 1 0 1 1 0 8 0
amappl3 88 128 0 121 1 0 1 1 0 8 0
amappl2 80 2981 0 2913 3 1 2 3 0 8 0
amappl1 72 18978 0 18475 27 17 10 20 0 8 0
amappl 80 1118 0 1061 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 69 0 53 1 0 1 1 0 8 0
uaddrrnd 24 499 0 477 1 0 1 1 0 8 0
uaddrbest 32 2 0 0 1 0 1 1 0 8 0
uaddr 24 499 0 477 1 0 1 1 0 8 0
vmmpekpl 168 7373 0 7341 2 0 2 2 0 8 0
vmmpepl 168 68569 0 66475 149 26 123 128 0 357 29
vmsppl 272 498 0 476 2 0 2 2 0 8 0
pdppl 4096 1004 0 957 8 1 7 7 0 8 0
pvpl 32 235960 0 220188 299 17 282 296 0 265 119
pmappl 200 498 0 476 3 1 2 2 0 8 0
extentpl 40 46 0 29 1 0 1 1 0 8 0
phpool 112 176 0 54 5 0 5 5 0 8 0


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot

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Nov 6, 2020, 2:50:18 AM11/6/20
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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