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From: Thomas Gleixner <tglx@linutronix.de>
To: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Darren Hart <dvhltc@us.ibm.com>,
	Rusty Russell <rusty@rustcorp.com.au>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: Bug: fio traps into kernel without exiting because futex has a deadloop
Date: Mon, 15 Jun 2009 10:27:02 +0200 (CEST)	[thread overview]
Message-ID: <alpine.LFD.2.00.0906151024260.2800@localhost.localdomain> (raw)
In-Reply-To: <1245045817.2560.363.camel@ymzhang>

On Mon, 15 Jun 2009, Zhang, Yanmin wrote:
> On Fri, 2009-06-12 at 10:39 +0200, Thomas Gleixner wrote:
>
> > +	ret = get_user_writeable(uaddr);
>
> X86 pte entry has no READABLE flag. Other platforms might have. If their pte
> only set WRITE flag, Is it poosible to create a similiar DOS attack with
> WRITEONLY area on such platforms?

Just checked with Peter. The kernel assumes that when its present we
can read. We looked at the arches that do support wr-only and it seems
that this is a valid assumption. i.e. we don't support wr-only
mappings.

Thanks,

	tglx

  parent reply	other threads:[~2009-06-15  8:27 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-11  3:08 Zhang, Yanmin
2009-06-11  5:55 ` Peter Zijlstra
2009-06-11  6:18   ` Peter Zijlstra
2009-06-11  6:21     ` Darren Hart
2009-06-11  8:33     ` Zhang, Yanmin
2009-06-11  9:36       ` Peter Zijlstra
2009-06-11 11:36       ` Peter Zijlstra
2009-06-12  0:59         ` Zhang, Yanmin
2009-06-12  8:12           ` Thomas Gleixner
2009-06-12  8:39             ` Thomas Gleixner
2009-06-15  6:03               ` Zhang, Yanmin
2009-06-15  7:57                 ` Thomas Gleixner
2009-06-16  3:16                   ` Zhang, Yanmin
2009-06-15  8:27                 ` Thomas Gleixner [this message]
2009-06-15  8:27                 ` Peter Zijlstra
2009-06-11  5:58 ` Darren Hart
2009-06-11  6:05   ` Zhang, Yanmin

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