xhci: make sure interrupts are restored to correct state

commit bd82873f23c9a6ad834348f8b83f3b6a5bca2c65 upstream.

spin_unlock_irqrestore() might be called with stale flags after
reading port status, possibly restoring interrupts to a incorrect
state.

If a usb2 port just finished resuming while the port status is read
the spin lock will be temporary released and re-acquired in a separate
function. The flags parameter is passed as value instead of a pointer,
not updating flags properly before the final spin_unlock_irqrestore()
is called.

Fixes: 8b3d45705e54 ("usb: Fix xHCI host issues on remote wakeup.")
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20191211142007.8847-7-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 79dabb14c2bf80093b4e8d0987dced3cdcd5098a..d527dcebed810638603aacf50714383d911b0844 100644 (file)
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -580,7 +580,7 @@ static u32 xhci_get_port_status(struct usb_hcd *hcd,
                struct xhci_bus_state *bus_state,
                __le32 __iomem **port_array,
                u16 wIndex, u32 raw_port_status,
-               unsigned long flags)
+               unsigned long *flags)
        __releases(&xhci->lock)
        __acquires(&xhci->lock)
 {
@@ -670,12 +670,12 @@ static u32 xhci_get_port_status(struct usb_hcd *hcd,
                        xhci_set_link_state(xhci, port_array, wIndex,
                                        XDEV_U0);
 
-                       spin_unlock_irqrestore(&xhci->lock, flags);
+                       spin_unlock_irqrestore(&xhci->lock, *flags);
                        time_left = wait_for_completion_timeout(
                                        &bus_state->rexit_done[wIndex],
                                        msecs_to_jiffies(
                                                XHCI_MAX_REXIT_TIMEOUT_MS));
-                       spin_lock_irqsave(&xhci->lock, flags);
+                       spin_lock_irqsave(&xhci->lock, *flags);
 
                        if (time_left) {
                                slot_id = xhci_find_slot_id_by_port(hcd,
@@ -834,7 +834,7 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
                        break;
                }
                status = xhci_get_port_status(hcd, bus_state, port_array,
-                               wIndex, temp, flags);
+                               wIndex, temp, &flags);
                if (status == 0xffffffff)
                        goto error;