From 585df1d90cb07a02ca6c7a7d339e56e46d50dafb Mon Sep 17 00:00:00 2001 From: Sarah Sharp Date: Tue, 2 Aug 2011 15:43:40 -0700 Subject: xhci: Remove TDs from TD lists when URBs are canceled. When a driver tries to cancel an URB, and the host controller is dying, xhci_urb_dequeue will giveback the URB without removing the xhci_tds that comprise that URB from the td_list or the cancelled_td_list. This can cause a race condition between the driver calling URB dequeue and the stop endpoint command watchdog timer. If the timer fires on a dying host, and a driver attempts to resubmit while the watchdog timer has dropped the xhci->lock to giveback a cancelled URB, URBs may be given back by the xhci_urb_dequeue() function. At that point, the URB's priv pointer will be freed and set to NULL, but the TDs will remain on the td_list. This will cause an oops in xhci_giveback_urb_in_irq() when the watchdog timer attempts to loop through the endpoints' td_lists, giving back killed URBs. Make sure that xhci_urb_dequeue() removes TDs from the TD lists and canceled TD lists before it gives back the URB. This patch should be backported to kernels as old as 2.6.36. Signed-off-by: Sarah Sharp Cc: Andiry Xu Cc: stable@kernel.org --- drivers/usb/host/xhci.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'drivers/usb/host/xhci.c') diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index 8e84acff113..3a0f695138f 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -1252,6 +1252,13 @@ int xhci_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status) if (temp == 0xffffffff || (xhci->xhc_state & XHCI_STATE_HALTED)) { xhci_dbg(xhci, "HW died, freeing TD.\n"); urb_priv = urb->hcpriv; + for (i = urb_priv->td_cnt; i < urb_priv->length; i++) { + td = urb_priv->td[i]; + if (!list_empty(&td->td_list)) + list_del_init(&td->td_list); + if (!list_empty(&td->cancelled_td_list)) + list_del_init(&td->cancelled_td_list); + } usb_hcd_unlink_urb_from_ep(hcd, urb); spin_unlock_irqrestore(&xhci->lock, flags); -- cgit v1.2.3-70-g09d2