On Tue, Nov 03, 2020 at 02:21:16AM +0100, Sasha Levin wrote:
> From: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>
>
> [ Upstream commit ca05f33316559a04867295dd49f85aeedbfd6bfd ]
>
> The reserved-memory overlap detection code fails to detect overlaps if
> either of the regions starts at address 0x0. The code explicitly checks
> for and ignores such regions, apparently in order to ignore dynamically
> allocated regions which have an address of 0x0 at this point. These
> dynamically allocated regions also have a size of 0x0 at this point, so
> fix this by removing the check and sorting the dynamically allocated
> regions ahead of any static regions at address 0x0.
>
> For example, there are two overlaps in this case but they are not
> currently reported:
>
> foo@0 {
> reg = <0x0 0x2000>;
> };
>
> bar@0 {
> reg = <0x0 0x1000>;
> };
>
> baz@1000 {
> reg = <0x1000 0x1000>;
> };
>
> quux {
> size = <0x1000>;
> };
>
> but they are after this patch:
>
> OF: reserved mem: OVERLAP DETECTED!
> bar@0 (0x00000000--0x00001000) overlaps with foo@0 (0x00000000--0x00002000)
> OF: reserved mem: OVERLAP DETECTED!
> foo@0 (0x00000000--0x00002000) overlaps with baz@1000 (0x00001000--0x00002000)
>
> Signed-off-by: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>
> Link: https://lore.kernel.org/r/ded6fd6b47b58741aabdcc6967f73eca6a3f311e.1603273666.git-series.vincent.whitchurch@xxxxxxxx
> Signed-off-by: Rob Herring <robh@xxxxxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
I'm not sure if this really needs to be backported. It's only fixing
what is essentially a minor debugging feature.
