[PATCH] drm/i915: Allow NULL memory region

[Dan Carpenter]

On Thu, Jul 25, 2024 at 08:48:35AM +0100, Tvrtko Ursulin wrote:
> 
> Hi,
> 
> On 12/07/2024 22:41, Jonathan Cavitt wrote:
> > Prevent a NULL pointer access in intel_memory_regions_hw_probe.
> 
> For future reference please include some impact assessment in patches tagged
> as fixes. Makes maintainers job, and even anyone's who tries to backport
> stuff to stable at some future date, much easier if it is known how
> important is the fix and in what circumstances can the problem it is fixing
> trigger.
> 

As someone doing backport work, I think this patch is fine.  Everyone
knows the impact of a NULL dereference in probe().

I guess with patches that add NULL dereferences, the trick is
understanding when people are adding NULL checks to make a static
checker happy or when it's a real bug.  But the fault lies with the
people adding NULL checks just to make the tools happy.  Some of these
pointless NULL checks end up in stable, but it's fine, extra NULL checks
never hurt anyone.  If the maintainer wants to be extra safe by adding
NULL checks then who are we to say otherwise.

In other words normal patches shouldn't have to say. "I'm not lying" at
the end.  It should be the pointless patches which say, "I'm doing a
pointless thing.  Don't bother backporting."

Most stable patch backports are done automatically and people have
various tools and scripts to do that.  If the tools don't handle this
patch automatically then they are defective.

regards,
dan carpenter