Re: [PATCH V2 1/3] PCI: rcar: Move the inbound index check

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Marek,

On Fri, Aug 9, 2019 at 7:48 PM <marek.vasut@gmail.com> wrote:
> From: Marek Vasut <marek.vasut+renesas@gmail.com>
>
> Since the $idx variable value is stored across multiple calls to
> rcar_pcie_inbound_ranges() function, and the $idx value is used to
> index registers which are written, subsequent calls might cause
> the $idx value to be high enough to trigger writes into nonexistent
> registers.
>
> Fix this by moving the $idx value check to the beginning of the loop.
>
> Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>

Thanks for your patch!

> --- a/drivers/pci/controller/pcie-rcar.c
> +++ b/drivers/pci/controller/pcie-rcar.c
> @@ -1048,6 +1048,10 @@ static int rcar_pcie_inbound_ranges(struct rcar_pcie *pcie,
>         mask &= ~0xf;
>
>         while (cpu_addr < cpu_end) {
> +               if (idx > MAX_NR_INBOUND_MAPS) {

Shouldn't that check be "idx >= MAX_NR_INBOUND_MAPS - 1" now?

> +                       dev_err(pcie->dev, "Failed to map inbound regions!\n");
> +                       return -EINVAL;
> +               }
>                 /*
>                  * Set up 64-bit inbound regions as the range parser doesn't
>                  * distinguish between 32 and 64-bit types.
> @@ -1067,11 +1071,6 @@ static int rcar_pcie_inbound_ranges(struct rcar_pcie *pcie,
>                 pci_addr += size;
>                 cpu_addr += size;
>                 idx += 2;
> -
> -               if (idx > MAX_NR_INBOUND_MAPS) {
> -                       dev_err(pcie->dev, "Failed to map inbound regions!\n");
> -                       return -EINVAL;
> -               }
>         }
>         *index = idx;

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds