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Commit 7ed603ec authored by Matt Evans's avatar Matt Evans Committed by Sarah Sharp
Browse files

xhci: Add an assertion to check for virt_dev=0 bug. 



During a "plug-unplug" stress test on an NEC xHCI card, a null pointer
dereference was observed.  xhci_address_device() dereferenced a null
virt_dev (possibly an erroneous udev->slot_id?); this patch adds a WARN_ON &
message to aid debug if it can be recreated.

Signed-off-by: default avatarMatt Evans <matt@ozlabs.org>
Signed-off-by: default avatarSarah Sharp <sarah.a.sharp@linux.intel.com>
parent 92a3da41

drivers/usb/host/xhci.c

+11 −0
Original line number Diff line number Diff line
@@ -2546,6 +2546,17 @@ int xhci_address_device(struct usb_hcd *hcd, struct usb_device *udev) 


	virt_dev = xhci->devs[udev->slot_id];



	if (WARN_ON(!virt_dev)) {

		/*

		 * In plug/unplug torture test with an NEC controller,

		 * a zero-dereference was observed once due to virt_dev = 0.

		 * Print useful debug rather than crash if it is observed again!

		 */

		xhci_warn(xhci, "Virt dev invalid for slot_id 0x%x!\n",

			udev->slot_id);

		return -EINVAL;

	}



	slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->in_ctx);

	/*

	 * If this is the first Set Address since device plug-in or