The code in hcd-pci.c that matches up EHCI controllers with their companion UHCI or OHCI controllers assumes that the private drvdata fields don't get set too early. However, it turns out that this field gets set by usb_create_hcd(), before hcd-pci expects it, and this can result in a crash when two controllers are probed in parallel (as can happen when a new controller card is hotplugged). The companions_rwsem lock was supposed to prevent this sort of thing, but usb_create_hcd() is called outside the scope of the rwsem. A simple solution is to check that the root-hub pointer has been initialized as well as the drvdata field. This doesn't happen until usb_add_hcd() is called; that call and the check are both protected by the rwsem. This patch should be applied to stable kernels from 3.10 onward. Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Reported-by: Stefani Seibold <stefani@xxxxxxxxxxx> Tested-by: Stefani Seibold <stefani@xxxxxxxxxxx> CC: <stable@xxxxxxxxxxxxxxx> --- [as1744] drivers/usb/core/hcd-pci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: usb-3.14/drivers/usb/core/hcd-pci.c =================================================================== --- usb-3.14.orig/drivers/usb/core/hcd-pci.c +++ usb-3.14/drivers/usb/core/hcd-pci.c @@ -75,7 +75,7 @@ static void for_each_companion(struct pc PCI_SLOT(companion->devfn) != slot) continue; companion_hcd = pci_get_drvdata(companion); - if (!companion_hcd) + if (!companion_hcd || !companion_hcd->self.root_hub) continue; fn(pdev, hcd, companion, companion_hcd); } -- 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
