From 284d20552461466b04d6bfeafeb1c47a8891b591 Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Thu, 5 Sep 2013 11:01:20 +0300 Subject: [PATCH] xhci: Fix oops happening after address device timeout 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 Reported-by: Giovanni Signed-off-by: Sarah Sharp Cc: stable@vger.kernel.org --- 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 411da1fc7ae8..aaa2906f7b78 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]) -- 2.20.1