Re: WARNING in perf_group_attach

syzbot suspects this bug was fixed by commit:

commit 311633b604063a8a5d3fbc74d0565b42df721f68
Author: Cong Wang [off-list ref]
Date:   Wed Jul 10 06:24:54 2019 +0000

     hsr: switch ->dellink() to ->ndo_uninit()

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1639a42ae00000
start commit:   6fbc7275 Linux 5.2-rc7
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=f6451f0da3d42d53
dashboard link: https://syzkaller.appspot.com/bug?extid=23fe48cbe532abffa52e
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1758795da00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11d2fa1ba00000

If the result looks correct, please mark the bug fixed by replying with:

#syz fix: hsr: switch ->dellink() to ->ndo_uninit()

For information about bisection process see: https://goo.gl/tpsmEJ#bisection