Re: kernel BUG at fs/inode.c:LINE! (2)

[syzbot <syzbot+c92c93d1f1aaaacdb9db@syzkaller.appspotmail.com>]

> On Fri, Aug 28, 2020 at 06:18:17AM -0700, syzbot wrote:
>> Hello,
>> 
>> syzbot found the following issue on:
>> 
>> HEAD commit:    d012a719 Linux 5.9-rc2
>> git tree:       upstream
>> console output: https://syzkaller.appspot.com/x/log.txt?x=15aa650e900000
>> kernel config:  https://syzkaller.appspot.com/x/.config?x=891ca5711a9f1650
>> dashboard link: https://syzkaller.appspot.com/bug?extid=c92c93d1f1aaaacdb9db
>> compiler:       clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81)
>> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12ecb939900000
>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=140a19a9900000
>> 
>> The issue was bisected to:
>> 
>> commit a9ed4a6560b8562b7e2e2bed9527e88001f7b682
>> Author: Marc Zyngier <maz@kernel.org>
>> Date:   Wed Aug 19 16:12:17 2020 +0000
>> 
>>     epoll: Keep a reference on files added to the check list
>> 
>> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=16a50519900000
>> final oops:     https://syzkaller.appspot.com/x/report.txt?x=15a50519900000
>> console output: https://syzkaller.appspot.com/x/log.txt?x=11a50519900000
>> 
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+c92c93d1f1aaaacdb9db@syzkaller.appspotmail.com
>> Fixes: a9ed4a6560b8 ("epoll: Keep a reference on files added to the check list")
>> 
>> ------------[ cut here ]------------
>> kernel BUG at fs/inode.c:1668!
>
> #syz set subsystem: fs

The specified label "subsystem" is unknown.
Please use one of the supported labels.

The following labels are suported:
missing-backport, no-reminders, prio: {low, normal, high}, subsystems: {.. see below ..}
The list of subsystems: https://syzkaller.appspot.com/upstream/subsystems?all=true

>
> This has been among btrfs bugs but this is is 'fs' and probably with a
> fix but I was not able to identify it among all the changes in
> eventpoll.c