[PATCH][next] drm/i915: Fix dereference of pointer backup before it is null checked

[Dan Carpenter]

On Tue, Oct 12, 2021 at 04:47:24PM +0200, Thomas Hellström wrote:
> Hi,
> 
> On 10/12/21 15:25, Colin King wrote:
> > From: Colin Ian King <colin.king at canonical.com>
> > 
> > The assignment of pointer backup_bo dereferences pointer backup before
> > backup is null checked, this could lead to a null pointer dereference
> > issue. Fix this by only assigning backup_bo after backup has been null
> > checked.
> > 
> > Addresses-Coverity: ("Dereference before null check")
> > Fixes: c56ce9565374 ("drm/i915 Implement LMEM backup and restore for suspend / resume")
> > Signed-off-by: Colin Ian King <colin.king at canonical.com>
> 
> There's not really a pointer dereference here, just pointer arithmetics, so
> the code should be safe (but admittedly fragile), so to keep Coverity happy,
> 
> Reviewed-by: Thomas Hellström <thomas.hellstrom at linux.intel.com>

Yeah.  I kind of feel like we shouldn't work around static checker bugs.
But when we do then there shouldn't be a Fixes tag.

regards,
dan carpenter