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
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