Commit cfbb8a84 authored Oct 04, 2019 by Mathias Nyman Committed by Greg Kroah-Hartman Oct 04, 2019

xhci: Fix NULL pointer dereference in xhci_clear_tt_buffer_complete()



udev stored in ep->hcpriv might be NULL if tt buffer is cleared
due to a halted control endpoint during device enumeration

xhci_clear_tt_buffer_complete is called by hub_tt_work() once it's
scheduled,  and by then usb core might have freed and allocated a
new udev for the next enumeration attempt.

Fixes: ef513be0 ("usb: xhci: Add Clear_TT_Buffer")
Cc: <stable@vger.kernel.org> # v5.3
Reported-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/1570190373-30684-9-git-send-email-mathias.nyman@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent ac343366

drivers/usb/host/xhci.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -5238,8 +5238,16 @@ static void xhci_clear_tt_buffer_complete(struct usb_hcd *hcd,
		unsigned int ep_index;
		unsigned long flags;

		/*
		* udev might be NULL if tt buffer is cleared during a failed device
		* enumeration due to a halted control endpoint. Usb core might
		* have allocated a new udev for the next enumeration attempt.
		*/

		xhci = hcd_to_xhci(hcd);
		udev = (struct usb_device *)ep->hcpriv;
		if (!udev)
		return;
		slot_id = udev->slot_id;
		ep_index = xhci_get_endpoint_index(&ep->desc);

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