Message-ID: <20250114234329.GB3557553@frogsfrogsfrogs>
Date: Tue, 14 Jan 2025 15:43:29 -0800
From: "Darrick J. Wong" <djwong@...nel.org>
To: Dmitry Vyukov <dvyukov@...gle.com>
Cc: Matthew Wilcox <willy@...radead.org>,
	Christian Brauner <brauner@...nel.org>,
	Kun Hu <huk23@...udan.edu.cn>,
	Andrey Konovalov <andreyknvl@...il.com>, jack@...e.cz,
	jlayton@...hat.com, tytso@....edu, adilger.kernel@...ger.ca,
	david@...morbit.com, viro@...iv.linux.org.uk, hch@....de,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: Bug: INFO_ task hung in lock_two_nondirectories

On Tue, Jan 14, 2025 at 10:15:28AM +0100, Dmitry Vyukov wrote:
> On Mon, 13 Jan 2025 at 19:08, Darrick J. Wong <djwong@...nel.org> wrote:
> >
> > On Mon, Jan 13, 2025 at 04:19:01PM +0000, Matthew Wilcox wrote:
> > > On Mon, Jan 13, 2025 at 03:38:57PM +0100, Christian Brauner wrote:
> > > > On Sun, Jan 12, 2025 at 06:00:24PM +0800, Kun Hu wrote:
> > > > > Hello,
> > > > >
> > > > > When using our customized fuzzer tool to fuzz the latest Linux kernel, the following crash (43s)
> > > > > was triggered.
> > > >
> > > > I think we need to come to an agreement at LSFMM or somewhere else that
> > > > we will by default ingore but reports from non-syzbot fuzzers. Because
> > > > we're all wasting time on them.
> >
> > No need to wait until LSFMM, I already agree with the premise of
> > deprioritizing/ignoring piles of reports that come in all at once with
> > very little analysis, an IOCCC-esque reproducer, and no effort on the
> > part of the reporter to do *anything* about the bug.
> >
> > While the Google syzbot dashboard has improved remarkably since 2018,
> > particularly in the past couple of years, thanks to the people who did
> > that!
> 
> And, thanks, Darrick!
> Most credit goes to Aleksandr Nogikh, who worked on improvements in
> the past years.
> We don't always have cycles to implement everything immediately, but
> we are listening.

You're welcome, and to both of you, thank you for all the improvements
over the last 8-9 years. :)

--D

> >  It's nice that I can fire off patches at the bot and it'll test
> > them.  That said, I don't perceive Google management to be funding much
> > of anyone to solve the problems that their fuzzer uncovers.
> >
> > This is to say nothing of the people who are coyly running their own
> > instances of syzbot sans dashboard and expecting me to download random
> > crap from Google Drive.  Hell no, I don't do that kind of thing in 2025.
> >
> > > I think it needs to be broader than that to also include "AI generated
> > > bug reports" (while not excluding AI-translated bug reports); see
> > >
> > > https://daniel.haxx.se/blog/2024/01/02/the-i-in-llm-stands-for-intelligence/
> > >
> > > so really, any "automated bug report" system is out of bounds unless
> > > previously arranged with the developers who it's supposed to be helping.
> >
> > Agree.  That's been my stance since syzbot first emerged in 2017-18.
> >
> > > We need to write that down somewhere in Documentation/process/ so we
> > > can point misguided people at it.
> > >
> > > We should also talk about how some parts of the kernel are basically
> > > unmaintained and unused, and that automated testing should be focused
> > > on parts of the kernel that are actually used.  A report about being
> > > able to crash a stock configuration of ext4 is more useful than being
> > > able to crash an unusual configuration of ufs.
> >
> > Or maybe we should try to make fuse + iouring fast enough that we can
> > kick all these old legacy drivers out to userspace. ;)
> >
> > > Distinguishing between warnings, BUG()s and actual crashes would also
> > > be a useful thing to put in this document.
> >
> > Yes.  And also state that panic_on_warn=1 is a signal that you wanted
> > fail(over) fast mode.
> >
> > --D

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