linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Willy Tarreau <w@1wt.eu>
To: Dipanjan Das <mail.dipanjan.das@gmail.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>,
	Denis Efremov <efremov@linux.com>, Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	syzkaller <syzkaller@googlegroups.com>,
	fleischermarius@googlemail.com, its.priyanka.bose@gmail.com
Subject: Re: INFO: task hung in __floppy_read_block_0
Date: Sun, 31 Jul 2022 11:53:07 +0200	[thread overview]
Message-ID: <20220731095307.GA12211@1wt.eu> (raw)
In-Reply-To: <CANX2M5b9PBp9i5v_akXshQqBFRT4dTHg+PR2pWpHPa5RBOEUTg@mail.gmail.com>

Hi,

On Thu, Jul 28, 2022 at 01:20:33PM -0700, Dipanjan Das wrote:
> On Thu, Jul 28, 2022 at 7:23 AM Lukas Bulwahn <lukas.bulwahn@gmail.com> wrote:
> >
> > Dipanjan, are you really sure that you want to report a "INFO: task
> > hung" bug identified with your syzkaller instance? Especially for a
> > floppy driver, probably in your case even just an emulated one
> > (right?). Reading data from floppies was always very slow as far as I
> > remember those times...
> 
> >From the bugs reported by syzkaller in the past, we observed that
> several of these "INFO: task hung in... " reports were considered and
> acted on, for example, this:
> https://groups.google.com/g/syzkaller-bugs/c/L0SBaHZ5bYc. For the
> reported issue, we noticed the read task stays blocked for 143
> seconds, which seemed to be one the higher, especially given that it
> is an emulated floppy drive (yes, you are right). If it deems normal,
> then we do apologize for our misassesment.

FWIW I've been running the repro here on machine running 5.19-rc8 and
equipped with a real floppy drive. The code is still running as I type,
it sounds like it's destroying the floppy disk in it but after 12 minutes
of torture, nothing happens.

Thus I'm a bit confused about what to look for. It's very likely that
there are still bugs left in this driver, but trying to identify them
and to validate a fix will be difficult if they cannot be reproduced.
Maybe they only happen under emulation due to timing issues.

As such, any hint about the exact setup and how long to wait to get
the error would be much appreciated.

Thanks,
Willy

  parent reply	other threads:[~2022-07-31  9:53 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-27 22:00 INFO: task hung in __floppy_read_block_0 Dipanjan Das
2022-07-28 14:23 ` Lukas Bulwahn
2022-07-28 20:20   ` Dipanjan Das
2022-07-29 14:32     ` Lukas Bulwahn
2022-07-31  9:53     ` Willy Tarreau [this message]
2022-07-31 10:46       ` Denis Efremov
2022-08-02  5:04       ` Dipanjan Das
2022-08-02 16:50         ` Willy Tarreau

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220731095307.GA12211@1wt.eu \
    --to=w@1wt.eu \
    --cc=axboe@kernel.dk \
    --cc=efremov@linux.com \
    --cc=fleischermarius@googlemail.com \
    --cc=its.priyanka.bose@gmail.com \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lukas.bulwahn@gmail.com \
    --cc=mail.dipanjan.das@gmail.com \
    --cc=syzkaller@googlegroups.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).