From: Al Viro <viro@zeniv.linux.org.uk>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
Dmitry Vyukov <dvyukov@google.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
syzkaller-bugs@googlegroups.com
Subject: Re: [PATCH v2] acct: fix possible deadlock in acct_pin_kill
Date: Thu, 4 Apr 2019 19:49:44 +0100 [thread overview]
Message-ID: <20190404184944.GD2217@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190404184448.GC2217@ZenIV.linux.org.uk>
On Thu, Apr 04, 2019 at 07:44:48PM +0100, Al Viro wrote:
> Huh? sb_writers is taken when we *open* the new file. Then we replace
> its ->path.mnt with a clone and transfer the write count from the original
> to new one. And close the old file while we are at it.
>
> >From sb_writers POV mainline has
> sb_start_write(new_sb) // in open
> sb_start_write(new_sb) // mnt_want_write() on clone
> last write to old_sb, then sb_end_write(old_sb) // acct_pin_kill()
> sb_end_write(new_sb) // mnt_drop_write(mnt)
> and you flip the order of the last two lines.
>
> Could you explain how exactly does your patch help whatever
> problem overlayfs has?
Ow... Sorry, -ENOCOFFEE...
Let me wake up properly and look at that thing again.
next prev parent reply other threads:[~2019-04-04 18:49 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-04 10:52 [PATCH v2] acct: fix possible deadlock in acct_pin_kill Amir Goldstein
2019-04-04 18:44 ` Al Viro
2019-04-04 18:49 ` Al Viro [this message]
2019-04-04 19:05 ` Al Viro
2019-04-04 19:33 ` Amir Goldstein
2019-04-11 19:10 ` Amir Goldstein
2019-04-04 19:19 ` Al Viro
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=20190404184944.GD2217@ZenIV.linux.org.uk \
--to=viro@zeniv.linux.org.uk \
--cc=amir73il@gmail.com \
--cc=dvyukov@google.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=miklos@szeredi.hu \
--cc=syzkaller-bugs@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.