Re: [PATCH] hfsplus: release bnode pages after use, not before

From: Sergei Antonov <saproj@gmail.com>
To: Hin-Tak Leung <htl10@users.sourceforge.net>
Cc: Vyacheslav Dubeyko <slava@dubeyko.com>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	Sasha Levin <sasha.levin@oracle.com>,
	Anton Altaparmakov <aia21@cam.ac.uk>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Christoph Hellwig <hch@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Sougata Santra <sougata@tuxera.com>
Subject: Re: [PATCH] hfsplus: release bnode pages after use, not before
Date: Mon, 8 Jun 2015 18:47:09 +0200	[thread overview]
Message-ID: <CABikg9z61CyTTaU7tbs5APD+3k-kX7knb-gm-OpTkwenS74tJg@mail.gmail.com> (raw)
In-Reply-To: <1433781680.24509.YahooMailBasic@web172301.mail.ir2.yahoo.com>

On 8 June 2015 at 18:41, Hin-Tak Leung <htl10@users.sourceforge.net> wrote:
> ------------------------------
> On Mon, Jun 8, 2015 4:45 PM BST Vyacheslav Dubeyko wrote:
>
>>On Sun, 2015-06-07 at 02:42 +0200, Sergei Antonov wrote:
>> Fix this bugreport by Sasha Levin:
>> http://lkml.org/lkml/2015/2/20/85 ("use after free")
>> Make sure mapped pages are available for the entire lifetime of hfs_bnode.
>>
>>
>>Sorry, I missed the point. What do you try to fix? How this change fixes
>>the issue?
>>
>>I think that maybe this fix makes sense. But it needs to describe it
>>more deeply. Could you describe the fix with more details?
>>
>>Thanks,
>>Vyacheslav Dubeyko.
>>
>>
>
> About this change, I also have two comments to make, one
> stylistic, one logical - you basically removed the ''#if 0",
> so I'd like to know how the "#if 0" came to be in the first place -
> I just haven't got the time to look through 'git blame' yet.
> Dead code should be removed, and that wasn't removed probably
> because it was too old i.e. already there for years.

"#if 0" has been there since the code was submitted to the kernel.

> Also there is no need to add those braces {}. I believe
> the kernel coding guideline explicitly stated not to,
> for one-statement bodies in loops?

Only for if statements (if I understand the coding style right).