BUG: Bad rss-counter state (3)

[syzbot]

Hello,

syzbot hit the following crash on upstream commit
a27fc14219f2e3c4a46ba9177b04d9b52c875532 (Mon Apr 16 21:07:39 2018 +0000)
Merge branch 'parisc-4.17-3' of  
git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
syzbot dashboard link:  
https://syzkaller.appspot.com/bug?extid=f2a1633f249cece865fe

So far this crash happened 8 times on upstream.
C reproducer: https://syzkaller.appspot.com/x/repro.c?id=6258099799195648
syzkaller reproducer:  
https://syzkaller.appspot.com/x/repro.syz?id=5162423375888384
Raw console output:  
https://syzkaller.appspot.com/x/log.txt?id=4959118615904256
Kernel config:  
https://syzkaller.appspot.com/x/.config?id=-5914490758943236750
compiler: gcc (GCC) 8.0.1 20180413 (experimental)

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Reported-by: syzbot+f2a1633f249cece865fe@xxxxxxxxxxxxxxxxxxxxxxxxx
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details.
If you forward the report, please keep this part and the footer.

BUG: Bad rss-counter state mm:00000000d5737ed7 idx:1 val:1
BUG: Bad rss-counter state mm:00000000d5737ed7 idx:3 val:-1


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