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Date:   Fri, 29 Jun 2018 16:42:57 +0300
From:   Dan Carpenter <dan.carpenter@oracle.com>
To:     Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc:     Dave Martin <Dave.Martin@arm.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Kate Stewart <kstewart@linuxfoundation.org>,
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        smatch@vger.kernel.org
Subject: Re: [PATCH v4 00/17] khwasan: kernel hardware assisted address
 sanitizer
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On Fri, Jun 29, 2018 at 01:26:14PM +0200, Luc Van Oostenryck wrote:
> On Fri, Jun 29, 2018 at 12:04:22PM +0100, Dave Martin wrote:
> > 
> > Can sparse be hacked to identify pointer subtractions where the pointers
> > are cannot be statically proved to point into the same allocation?
> 
> sparse only see the (deatils of) the function it analyses and all
> visible declarations, nothing more.
> 
> It would be more a job for smatch which do global analysis.
> But to identify such subtractions yu must already have a (good)
> pointer alias analysis which I don't think smatch do (but I can
> be wrong, Dan & smatch's ml added in CC).

That would be hard to manage.  Maybe in a year from now...

Pointer math errors tend to get caught pretty quick because they're on
the success path so I don't imagine there are huge numbers of bugs.

regards,
dan carpenter