On Thu, 14 Jan 2016, Joerg Roedel wrote: > On Thu, Jan 14, 2016 at 03:01:14PM +0100, Oliver Neukum wrote: > > On Thu, 2016-01-14 at 13:50 +0100, Stefani Seibold wrote: > > > A unplug of an USB 1.0 OHCI controller express card will result in a > > > kernel crash. The express card is attached via thunderbolt and a sonnet > > > express card to thunderbolt adapter. The computer hangs after the > > > unplug, only a power fix the situation. > > > > > > This is the kernel log of a kernel 4.4 via netconsole: > > > > > > pciehp 0000:06:03.0:pcie24: Card not present on Slot(3) > > > pciehp 0000:06:03.0:pcie24: slot(3): Link Down event > > > pciehp 0000:06:03.0:pcie24: Link Down event ignored on slot(3): already powering off > > > ehci-pci 0000:0b:00.2: HC died; cleaning up > > > ehci-pci 0000:0b:00.2: remove, state 4 > > > usb usb5: USB disconnect, device number 1 > > > pciehp 0000:00:1c.4:pcie04: Card not present on Slot(4) > > > pciehp 0000:00:1c.4:pcie04: slot(4): Link Down event > > > ehci-pci 0000:0b:00.2: USB bus 5 deregistered > > > ohci-pci 0000:0b:00.1: HC died; cleaning up > > > ohci-pci 0000:0b:00.1: remove, state 4 > > > usb usb7: USB disconnect, device number 1 > > > pciehp 0000:00:1c.4:pcie04: Link Down event ignored on slot(4): already powering off > > > ohci-pci 0000:0b:00.1: USB bus 7 deregistered > > > ohci-pci 0000:0b:00.0: HC died; cleaning up > > > ohci-pci 0000:0b:00.0: remove, state 4 > > > usb usb6: USB disconnect, device number 1 > > > ------------[ cut here ]------------ > > > kernel BUG at drivers/iommu/intel-iommu.c:3592! > > > > This is likely the crucial information. The IOMMU is unhappy. > > The only explanation for this is that the device driver calls into the > iommu code after the BUS_NOTIFY_REMOVED_DEVICE notifier ran. I see in > the stack-trace below that device_release_driver() is called from an > unusual place in pci code. > > Unless there is a good explanation for calling device_release_driver() > after the BUS_NOTIFY_REMOVED_DEVICE notifier, this is no bug in the > iommu code. I don't think that is what happened. The BUS_NOTIFY_REMOVED_DEVICE notifier is sent by device_del(), which is called (indirectly) by pci_remove_bus_device(). The device driver's remove routine -- which is what called into the iommu code -- is invoked through device_release_driver(), which is called (indirectly) by pci_stop_bus_device(). Since pci_stop_and_remove_bus_device() calls pci_stop_bus_device() before pci_remove_bus_device(), the notifier does not get sent until after the iommu code runs. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
