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| author | Michel Dänzer <michel.daenzer@amd.com> | 2015-01-19 17:53:20 +0900 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2015-03-01 23:34:15 +0100 |
| commit | bd4b3c108399d1f842472b77bde81d090d936f0f (patch) | |
| tree | 80056c62f177dab4d2bcda38b6be78f1d6811bf9 | |
| parent | 109102cb30e106fd9e06dcd49a0abfcabacb6439 (diff) | |
| download | lwn-bd4b3c108399d1f842472b77bde81d090d936f0f.tar.gz lwn-bd4b3c108399d1f842472b77bde81d090d936f0f.zip | |
PCI: Fix infinite loop with ROM image of size 0
commit 16b036af31e1456cb69243a5a0c9ef801ecd1f17 upstream.
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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | drivers/pci/rom.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c index c5d0a08a8747..d6d499782fb4 100644 --- a/drivers/pci/rom.c +++ b/drivers/pci/rom.c @@ -69,6 +69,7 @@ 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 { @@ -91,9 +92,9 @@ 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 */ |