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From: Michael Buesch <mb@bu3sch.de>
To: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Greg KH <gregkh@suse.de>,
	linux-kernel@vger.kernel.org, Dave Jones <davej@redhat.com>
Subject: Re: NULL pointer dereference in sysfs_readdir
Date: Sun, 22 Oct 2006 12:40:41 +0200	[thread overview]
Message-ID: <200610221240.42061.mb@bu3sch.de> (raw)
In-Reply-To: <453B352A.5050700@s5r6.in-berlin.de>

On Sunday 22 October 2006 11:08, Stefan Richter wrote:
> > Yeah, I found that offset, too, but:
> > 
> > There is only one usage of s_dentry
> > if (next->s_dentry)
> > 
> > But _before_ that there already comes
> > if (!next->s_element)
> > 
> > So, if "next" was NULL, it would already oops there.
> 
> What if "next" became NULL afterwards?

Hm, yeah. Makes kind of sense.

> I know it's unlikely (but so is 
> the whole bug, given that we have just one reporter despite the bug's
> age), but is it impossible? IOW does sysfs_readdir have any indirect
> mutex protection?

I think it's protected by the BKL, but I dunno if that's sufficient here.

-- 
Greetings Michael.

  reply	other threads:[~2006-10-22 10:41 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-10-21  8:43 NULL pointer dereference in sysfs_readdir Stefan Richter
2006-10-21 20:04 ` Michael Buesch
2006-10-21 21:09   ` Stefan Richter
2006-10-21 21:25     ` Michael Buesch
2006-10-22  9:08       ` Stefan Richter
2006-10-22 10:40         ` Michael Buesch [this message]
2006-10-22 18:11         ` Dave Jones
2006-10-30 12:36 ` Maneesh Soni
2006-10-31  8:36   ` Stefan Richter

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