http://bugzilla.kernel.org/show_bug.cgi?id=12748
--- Comment #23 from ykzhao <yakui.z...@intel.com> 2009-06-22 02:32:47 --- (In reply to comment #22) > I agree with the proposal as a good fix for PROBLEM-1, and it will be trivial > to fix some of the other problems later. > > HOWEVER > > You do need to fix PROBLEM-2 as well (see comment #19), in the sense that we > MUST unregister devices from the power resources (because of the linked > list). > Otherwise, you will have references to freed memory in the linked lists on the > power resources, which is unacceptable. > > Example: USB EHCI and UHCI in most ThinkPads (you can use thinkpads to > reproduce the bug I describe): > > Firmware has a single power resource, "PUBS", that is related to ACPI devices > for the single EHCI and for the four UHCI devices. > > 1. Your patch will notice that the power resource is already in D0, and > register a link between PUBS and EHCI. It will also do the same for UHCI. > This is correct, and good. > > 2. User rmmods EHCI or UHCI: the 2.6.29 would NOT unregister the link between > PUBS and EHCI/UHCI... (didn't check if you already fixed it in 2.6.30). If the PCI device state is set to D3 when unloading the driver, the link between the device and power resource will be freed. But it seems that the PCI device state is not touched when unloading most pci driver. In such case the link between the device and power resource can't be freed. In fact this issue is related with which state the device is in when there is no device driver. D0 / D3? Or the device state should not be touched when there is no device driver. Thanks. > > 3. Something in the kernel tries to use the linked list of devices related to > a > power-resource: OOPS (if you are lucky), memory corruption (if you're > unlucky), etc. > > So, we need to _ALWAYS_ unregister the devices from the power resources. This > need to be fixed first. -- Configure bugmail: http://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug. ------------------------------------------------------------------------------ Are you an open source citizen? Join us for the Open Source Bridge conference! Portland, OR, June 17-19. Two days of sessions, one day of unconference: $250. Need another reason to go? 24-hour hacker lounge. Register today! http://ad.doubleclick.net/clk;215844324;13503038;v?http://opensourcebridge.org _______________________________________________ acpi-bugzilla mailing list acpi-bugzilla@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/acpi-bugzilla
