syzbot suspects this bug was fixed by commit:
commit 68faa679b8be1a74e6663c21c3a9d25d32f1c079
Author: Will Deacon <will@xxxxxxxxxx>
Date: Thu Dec 19 12:02:03 2019 +0000
chardev: Avoid potential use-after-free in 'chrdev_open()'
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14412659e00000
start commit: 81b6b964 Merge branch 'master' of git://git.kernel.org/pub..
git tree: upstream
kernel config: https://syzkaller.appspot.com/x/.config?x=d98e4bd76baeb821
dashboard link: https://syzkaller.appspot.com/bug?extid=1c85a21f1c6bc88eb388
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=147ad0a6e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15483312e00000
If the result looks correct, please mark the bug fixed by replying with:
#syz fix: chardev: Avoid potential use-after-free in 'chrdev_open()'
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
