Re: [PATCH] drm/i915: Do not dereference pointers from ring buffer in evict event

From: Daniel Vetter
Date: Tue Mar 18 2014 - 15:50:32 EST


On Tue, Mar 18, 2014 at 11:31:36AM -0400, Steven Rostedt wrote:
> On Tue, 18 Mar 2014 11:27:37 -0400
> Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> > The TP_printk() should never dereference any pointers, because the ring
> > buffer can be read at some unknown time in the future. If a device no
> > longer exists, it can cause a kernel oops. This also makes this
> > event useless when saving the ring buffer in userspaces tools such as
> > perf and trace-cmd.
> >
> > The i915_gem_evict_vm dereferences the vm pointer which may also not
> > exist when the ring buffer is read sometime in the future.
> >
> > Link: http://lkml.kernel.org/r/1395095198-20034-3-git-send-email-artagnon@xxxxxxxxx
> > Reported-by: Ramkumar Ramachandra <artagnon@xxxxxxxxx> Cc:
> > stable@xxxxxxxxxxxxxxx # 3.13+
>
> Bah, claw's mail is playing havoc with my line wraps. Please fix the
> above when applying, or I can send anothe patch. Thanks :-)
>
> I had to re-insert the patch due to it but didn't see the screw up with
> the Cc of stable.

Patch applied and cc: stable fixed, thanks.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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