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authorMichel Dänzer <michel.daenzer@amd.com>2015-01-19 09:53:20 +0100
committerBjorn Helgaas <bhelgaas@google.com>2015-01-24 00:42:59 +0100
commit16b036af31e1456cb69243a5a0c9ef801ecd1f17 (patch)
tree843e54f9032b465a487485e6a4a1471e8409c03c /drivers/pci/rom.c
parentLinux 3.19-rc1 (diff)
downloadlinux-16b036af31e1456cb69243a5a0c9ef801ecd1f17.tar.xz
linux-16b036af31e1456cb69243a5a0c9ef801ecd1f17.zip
PCI: Fix infinite loop with ROM image of size 0
If the image size would ever read as 0, pci_get_rom_size() could keep processing the same image over and over again. Exit the loop if we ever read a length of zero. This fixes a soft lockup on boot when the radeon driver calls pci_get_rom_size() on an AMD Radeon R7 250X PCIe discrete graphics card. [bhelgaas: changelog, reference] Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1386973 Reported-by: Federico <federicotg@gmail.com> Signed-off-by: Michel Dänzer <michel.daenzer@amd.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> CC: stable@vger.kernel.org
Diffstat (limited to 'drivers/pci/rom.c')
-rw-r--r--drivers/pci/rom.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c
index f955edb9bea7..eb0ad530dc43 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 */