From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20130911042906.447730986@goodmis.org> Date: Wed, 11 Sep 2013 00:28:32 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Oleksij Rempel , Sarah Sharp Subject: [085/251] xhci: fix null pointer dereference on ring_doorbell_for_active_rings References: <20130911042707.738353451@goodmis.org> Content-Disposition: inline; filename=0085-xhci-fix-null-pointer-dereference-on-ring_doorbell_f.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.6.11.9-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Oleksij Rempel [ Upstream commit d66eaf9f89502971fddcb0de550b01fa6f409d83 ] in some cases where device is attched to xhci port and do not responding, for example ath9k_htc with stalled firmware, kernel will crash on ring_doorbell_for_active_rings. This patch check if pointer exist before it is used. This patch should be backported to kernels as old as 2.6.35, that contain the commit e9df17eb1408cfafa3d1844bfc7f22c7237b31b8 "USB: xhci: Correct assumptions about number of rings per endpoint" Signed-off-by: Oleksij Rempel Signed-off-by: Sarah Sharp Cc: stable@vger.kernel.org Signed-off-by: Steven Rostedt --- drivers/usb/host/xhci-ring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 8848616..21a01ac 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -434,7 +434,7 @@ static void ring_doorbell_for_active_rings(struct xhci_hcd *xhci, /* A ring has pending URBs if its TD list is not empty */ if (!(ep->ep_state & EP_HAS_STREAMS)) { - if (!(list_empty(&ep->ring->td_list))) + if (ep->ring && !(list_empty(&ep->ring->td_list))) xhci_ring_ep_doorbell(xhci, slot_id, ep_index, 0); return; } -- 1.7.10.4