From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> When a command times out, the command ring is first aborted, and then stopped. If the command ring is empty when it is stopped the stop event will point to next command which is not yet set. xHCI tries to handle this next event often causing an oops. Don't handle command completion events on stopped cmd ring if ring is empty. This patch should be backported to kernels as old as 3.7, that contain the commit b92cc66c047ff7cf587b318fe377061a353c120f "xHCI: add aborting command ring function" Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> Reported-by: Giovanni <giovanni.nervi@xxxxxxxxx> Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx --- drivers/usb/host/xhci-ring.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 411da1f..aaa2906 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -1414,6 +1414,12 @@ static void handle_cmd_completion(struct xhci_hcd *xhci, inc_deq(xhci, xhci->cmd_ring); return; } + /* There is no command to handle if we get a stop event when the + * command ring is empty, event->cmd_trb points to the next + * unset command + */ + if (xhci->cmd_ring->dequeue == xhci->cmd_ring->enqueue) + return; } switch (le32_to_cpu(xhci->cmd_ring->dequeue->generic.field[3]) -- 1.8.3.3 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
