Hi Alex, Thanks for the bug report and sorry for the troubles. I've already got a debug patch here: http://thread.gmane.org/gmane.linux.kernel/857228/focus=857468 Perhaps you can try it too? Len, in the mean time, can you please apply this as an emergency, "let's not crash anyone else's machine" while I try and figure out why the ACPI video driver breaks my assumptions? Troy, I applied your S-o-B, but maybe that was not a good assumption on my part? To be sure, could you please respond with your S-o-B? Thanks. /ac, wearing a brown paper bag From: Troy Moure <twmoure@xxxxxxxxx> ACPI: prevent NULL deref in acpi_get_pci_dev() When the ACPI video driver initializes, it does a namespace walk looking for for supported devices. When we find an appropriate handle, we walk up the ACPI tree looking for a PCI root bus, and then walk back down the PCI bus, assuming that every device inbetween is a P2P bridge. This assumption is not correct, and is reported broken on at least: Dell Latitude E6400 ThinkPad X61 Dell XPS M1330 Add a NULL deref check to prevent boot panics. Reported-by: Alessandro Suardi <alessandro.suardi@xxxxxxxxx> Signed-off-by: Troy Moure <twmoure@xxxxxxxxx> Signed-off-by: Alex Chiang <achiang@xxxxxx> --- diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index 8a5bf3b..55b5b90 100644 --- a/drivers/acpi/pci_root.c +++ b/drivers/acpi/pci_root.c @@ -395,7 +395,7 @@ struct pci_dev *acpi_get_pci_dev(acpi_handle handle) fn = adr & 0xffff; pdev = pci_get_slot(pbus, PCI_DEVFN(dev, fn)); - if (hnd == handle) + if (!pdev || hnd == handle) break; pbus = pdev->subordinate; -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
