diff options
| author | Oleksij Rempel <linux@rempel-privat.de> | 2013-07-21 15:36:19 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-08-04 16:25:46 +0800 |
| commit | 00a71cc4ea7cfdc02cf494fbeecb110466480c87 (patch) | |
| tree | d261ba0142c05594af2be7ceec1799ef0061cea7 | |
| parent | 2d75d5d8384dc3a2abc1113d0bb0c7333e669042 (diff) | |
xhci: fix null pointer dereference on ring_doorbell_for_active_rings
commit d66eaf9f89502971fddcb0de550b01fa6f409d83 upstream.
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 <linux@rempel-privat.de>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/host/xhci-ring.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 843b3e8ca4b..1770ed586a9 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; } |