Date: Fri, 20 Mar 2009 19:32:10 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: "K.Prasad" <prasad@linux.vnet.ibm.com>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Benjamin Herrenschmidt <benh@au1.ibm.com>,
       Frederic Weisbecker <fweisbec@gmail.com>,
       Maneesh Soni <maneesh@in.ibm.com>, Roland McGrath <roland@redhat.com>,
       Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [Patch 01/11] Introducing generic hardware breakpoint handler
	interfaces
Message-ID: <20090320183210.GC31629@elte.hu>
References: <20090319234804.GB10517@in.ibm.com> <Pine.LNX.4.44L0.0903201006120.2686-100000@iolanthe.rowland.org>
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* Alan Stern <stern@rowland.harvard.edu> wrote:

> > +	/* Check that the virtual address is in the proper range */
> > +	if (tsk) {
> > +		if (!arch_check_va_in_userspace(bp->info.address, tsk))
> > +			return -EFAULT;
> > +	} else {
> > +		if (!arch_check_va_in_kernelspace(bp->info.address))
> > +			return -EFAULT;
> > +	}
> 
> Roland pointed out that these checks need to take into account the 
> length of the breakpoint.  For example, in 
> arch_check_va_in_userspace() it isn't sufficient for the start of 
> the breakpoint region to be a userspace address; the end of the 
> breakpoint region must also be in userspace.

i pointed it out - but yes, this needs to be fixed.

	Ingo
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