This is a note to let you know that I've just added the patch titled PCI: Fix infinite loop with ROM image of size 0 to the 3.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: pci-fix-infinite-loop-with-rom-image-of-size-0.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 16b036af31e1456cb69243a5a0c9ef801ecd1f17 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <michel.daenzer@xxxxxxx> Date: Mon, 19 Jan 2015 17:53:20 +0900 Subject: PCI: Fix infinite loop with ROM image of size 0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <michel.daenzer@xxxxxxx> 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@xxxxxxxxx> Signed-off-by: Michel Dänzer <michel.daenzer@xxxxxxx> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/pci/rom.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) --- a/drivers/pci/rom.c +++ b/drivers/pci/rom.c @@ -69,6 +69,7 @@ size_t pci_get_rom_size(struct pci_dev * { void __iomem *image; int last_image; + unsigned length; image = rom; do { @@ -91,9 +92,9 @@ size_t pci_get_rom_size(struct pci_dev * 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 */ Patches currently in stable-queue which might be from michel.daenzer@xxxxxxx are queue-3.14/pci-fix-infinite-loop-with-rom-image-of-size-0.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html