Re: WARNING: bad usercopy in fanotify_read

syzbot has bisected this bug to:

commit a8b13aa20afb69161b5123b4f1acc7ea0a03d360
Author: Amir Goldstein [off-list ref]
Date:   Thu Jan 10 17:04:36 2019 +0000

     fanotify: enable FAN_REPORT_FID init flag

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=11e78d6f200000
start commit:   a8b13aa2 fanotify: enable FAN_REPORT_FID init flag
git tree:       upstream
final crash:    https://syzkaller.appspot.com/x/report.txt?x=13e78d6f200000
console output: https://syzkaller.appspot.com/x/log.txt?x=15e78d6f200000
kernel config:  https://syzkaller.appspot.com/x/.config?x=e9d91b7192a5e96e
dashboard link: https://syzkaller.appspot.com/bug?extid=2c49971e251e36216d1f
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1287516f200000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17ee410b200000

Reported-by: syzbot+2c49971e251e36216d1f@syzkaller.appspotmail.com
Fixes: a8b13aa2 ("fanotify: enable FAN_REPORT_FID init flag")