From: Dmitry Vyukov <dvyukov@google.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: syzbot <syzkaller@googlegroups.com>,
syzbot <syzbot+46fe899420456e014d6b@syzkaller.appspotmail.com>,
areeba.ahmed@futuregulfpak.com, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: Re: [syzbot] INFO: task hung in fuse_simple_request
Date: Fri, 6 Aug 2021 13:09:47 +0200 [thread overview]
Message-ID: <CACT4Y+bh6TGBJAwR5UjoPkCLgiSUypUBWVVMcp9bVEWJbFrASA@mail.gmail.com> (raw)
In-Reply-To: <CAJfpegu2fR3cP+eR24a1+WBBR=hvz8p2cTfK0x4sNz5c-MMH3Q@mail.gmail.com>
On Fri, 6 Aug 2021 at 11:34, Miklos Szeredi <miklos@szeredi.hu> wrote:
> > > Hi,
> > >
> > > I'm not sure what to make of this report.
> > >
> > > Does syzbot try to kill all tasks before generating such a hung task report?
> > >
> > > Does it use the fuse specific /sys/fs/fuse/connections/*/abort to
> > > terminate stuck filesystems?
> >
> > Hi Miklos,
> >
> > Grepping the C reproducer for "/sys/fs/fuse/connections", it seems
> > that it tries to abort all connections.
>
> Hi Dmitry,
>
> So this could indicate a bug in the abort code of fuse, or it could
> indicate that the test case DoS-es the system so that the abort code
> simply doesn't get the resources to execute.
>
> Can the two be differentiated somehow?
I think we need to take a closer look at what happens here. I've filed
https://github.com/google/syzkaller/issues/498#issuecomment-894185550
for this.
The overall idea is that DoS should not be possible by construction
with various sandboxing so that the system does not report what is not
a bug at all. But it's not always easy to achieve.
prev parent reply other threads:[~2021-08-06 11:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-13 21:13 INFO: task hung in fuse_simple_request syzbot
2021-07-17 2:28 ` [syzbot] " syzbot
2021-08-06 8:54 ` Miklos Szeredi
2021-08-06 9:15 ` Dmitry Vyukov
2021-08-06 9:34 ` Miklos Szeredi
2021-08-06 11:09 ` Dmitry Vyukov [this message]
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