linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Kirill Tkhai <ktkhai@virtuozzo.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] fuse: Fix race in fuse_writepage_in_flight()
Date: Tue, 15 Jan 2019 18:55:21 +0300	[thread overview]
Message-ID: <b198f480-9ce7-9663-40b1-193a05846c95@virtuozzo.com> (raw)
In-Reply-To: <CAJfpegvOgA+Wd3vTRqYQP7p_SJ11YCffquP_R=WRHwqYD4b=Ng@mail.gmail.com>

On 15.01.2019 18:37, Miklos Szeredi wrote:
> On Thu, Jan 10, 2019 at 12:03 PM Kirill Tkhai <ktkhai@virtuozzo.com> wrote:
>>
>> On 10.01.2019 14:00, Miklos Szeredi wrote:
>>> On Thu, Jan 10, 2019 at 11:48 AM Kirill Tkhai <ktkhai@virtuozzo.com> wrote:
>>>>
>>>> Hi, Miklos,
>>>>
>>>> any comments about this?
>>>
>>> Is there a reproducer?  ISTR that fsx-linux with mmaps enabled was
>>> good for stressing the writeback_cache code.
>>
>> There is no a reproducer, since I found that by eyes during preparation of another patchset.
> 
> That's good.  It would even better to have a reproducer, but it
> doesn't look easy...
> 
> Completely redid this and reordered the patchset so this change is
> made before the locking changes actually introduce the bug.

Hm, I meant that I found this during preparation of the patchset,
but not that fi->lock patchset introduces the bug. I don't think
the patchset is involved:

1)before we had race, because different locks fc->lock and fiq->waitq.lock
are taken in fuse_dev_read() and fuse_writepage_in_flight();
2)after we have the same race, and the locks are fi->lock and fiq->waitq.lock.

>See fuse.git#for-next.

The renewed patch looks correct for me.

Thanks,
Kirill

  reply	other threads:[~2019-01-15 15:55 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-26  9:46 [PATCH 1/2] fuse: Fix race in fuse_writepage_in_flight() Kirill Tkhai
2018-11-26  9:46 ` [PATCH 2/2] fuse: Replace page without copying " Kirill Tkhai
2019-01-15 15:39   ` Miklos Szeredi
2019-01-15 16:14     ` Kirill Tkhai
2019-01-15 16:36       ` Miklos Szeredi
2019-01-15 16:38         ` Kirill Tkhai
2019-01-10 10:48 ` [PATCH 1/2] fuse: Fix race " Kirill Tkhai
2019-01-10 11:00   ` Miklos Szeredi
2019-01-10 11:03     ` Kirill Tkhai
2019-01-15 15:37       ` Miklos Szeredi
2019-01-15 15:55         ` Kirill Tkhai [this message]
2019-01-15 16:03           ` Miklos Szeredi
2019-01-15 16:05             ` Kirill Tkhai

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=b198f480-9ce7-9663-40b1-193a05846c95@virtuozzo.com \
    --to=ktkhai@virtuozzo.com \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=miklos@szeredi.hu \
    /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).