From: Christoph Hellwig <hch@infradead.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>,
Steven Rostedt <rostedt@goodmis.org>,
Theodore Ts'o <tytso@mit.edu>,
LKML <linux-kernel@vger.kernel.org>,
linux-ext4@vger.kernel.org,
Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: [BUG] ext4 trace events cause NULL pointer dereferences
Date: Thu, 22 Jul 2010 01:49:57 -0400 [thread overview]
Message-ID: <20100722054957.GA11670@infradead.org> (raw)
In-Reply-To: <20100721222508.8704.A69D9226@jp.fujitsu.com>
On Wed, Jul 21, 2010 at 10:31:20PM +0900, KOSAKI Motohiro wrote:
> But, I don't think this is proper fix because we don't want any overhead
> if the tracepoint is disabled.
>
> So, How do we check NULL in TP_fast_assign()?
I think ext4 is simply using an incorrectly typed tracepoint here.
If you want it to be useful in any way it needs a sb paramter and
an optional inode paramter, not the allocation context.
Also the whole ext4_mb_release_group_pa function seems to be a bit
misdesigned. The code using ac is a totally separate block at the
end of the function and does work that's unrelated to the rest
of the function. Just making it a separate helper can calling it
only from those places that have the allocation context would make
the code more clear.
next prev parent reply other threads:[~2010-07-22 5:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-16 8:48 [BUG] ext4 trace events cause NULL pointer dereferences Li Zefan
2010-07-21 13:31 ` KOSAKI Motohiro
2010-07-21 14:16 ` Steven Rostedt
2010-07-21 14:21 ` Frederic Weisbecker
2010-07-22 5:45 ` Li Zefan
2010-07-22 5:49 ` Christoph Hellwig [this message]
2010-07-23 1:13 ` Ted Ts'o
2010-07-23 5:47 ` KOSAKI Motohiro
2010-07-23 9:11 ` Theodore Tso
2010-07-23 9:19 ` Li Zefan
2010-07-26 2:20 ` Li Zefan
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