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Message-ID: <CADnq5_O7ok+OtHxuPWgu2J-LxhqrJGJ0H9cinWLV8toGcCXdsQ@mail.gmail.com>
Date: Mon, 19 Jan 2015 13:48:57 -0500
From: Alex Deucher <alexdeucher@...il.com>
To: Michel Dänzer <michel@...nzer.net>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>,
Linux PCI <linux-pci@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>,
Maling list - DRI developers
<dri-devel@...ts.freedesktop.org>
Subject: Re: [PATCH v2] pci: Fix infinite loop with ROM image of size 0
On Mon, Jan 19, 2015 at 3:53 AM, Michel Dänzer <michel@...nzer.net> wrote:
> From: Michel Dänzer <michel.daenzer@....com>
>
> If the image size would ever read as 0, pci_get_rom_size could keep
> processing the same image over and over again.
>
> Reported-by: Federico <federicotg@...il.com>
> Cc: stable@...r.kernel.org
> Signed-off-by: Michel Dänzer <michel.daenzer@....com>
Reviewed-by: Alex Deucher <alexander.deucher@....com>
> ---
>
> v2:
> * Use unsigned instead of u16 for the local length variable (not sure if
> the multiplication by 512 could overflow otherwise)
> * Integrate length condition into while statement
> * Add stable tag
>
> drivers/pci/rom.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c
> index f955edb..eb0ad53 100644
> --- a/drivers/pci/rom.c
> +++ b/drivers/pci/rom.c
> @@ -71,6 +71,7 @@ size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size)
> {
> void __iomem *image;
> int last_image;
> + unsigned length;
>
> image = rom;
> do {
> @@ -93,9 +94,9 @@ size_t pci_get_rom_size(struct pci_dev *pdev, void __iomem *rom, size_t size)
> if (readb(pds + 3) != 'R')
> break;
> last_image = readb(pds + 21) & 0x80;
> - /* this length is reliable */
> - image += readw(pds + 16) * 512;
> - } while (!last_image);
> + length = readw(pds + 16);
> + image += length * 512;
> + } while (length && !last_image);
>
> /* never return a size larger than the PCI resource window */
> /* there are known ROMs that get the size wrong */
> --
> 2.1.4
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@...ts.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
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