xhci: make sure interrupts are restored to correct state

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.

Cc: <stable@vger.kernel.org> # v3.12+
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>

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 4b870cd..7a3a29e 100644 (file)
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -806,7 +806,7 @@ static void xhci_del_comp_mod_timer(struct xhci_hcd *xhci, u32 status,
 
 static int xhci_handle_usb2_port_link_resume(struct xhci_port *port,
                                             u32 *status, u32 portsc,
-                                            unsigned long flags)
+                                            unsigned long *flags)
 {
        struct xhci_bus_state *bus_state;
        struct xhci_hcd *xhci;
@@ -860,11 +860,11 @@ static int xhci_handle_usb2_port_link_resume(struct xhci_port *port,
                xhci_test_and_clear_bit(xhci, port, PORT_PLC);
                xhci_set_link_state(xhci, port, 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, xhci,
@@ -967,7 +967,7 @@ static void xhci_get_usb3_port_status(struct xhci_port *port, u32 *status,
 }
 
 static void xhci_get_usb2_port_status(struct xhci_port *port, u32 *status,
-                                     u32 portsc, unsigned long flags)
+                                     u32 portsc, unsigned long *flags)
 {
        struct xhci_bus_state *bus_state;
        u32 link_state;
@@ -1017,7 +1017,7 @@ static void xhci_get_usb2_port_status(struct xhci_port *port, u32 *status,
 static u32 xhci_get_port_status(struct usb_hcd *hcd,
                struct xhci_bus_state *bus_state,
        u16 wIndex, u32 raw_port_status,
-               unsigned long flags)
+               unsigned long *flags)
        __releases(&xhci->lock)
        __acquires(&xhci->lock)
 {
@@ -1140,7 +1140,7 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
                }
                trace_xhci_get_port_status(wIndex, temp);
                status = xhci_get_port_status(hcd, bus_state, wIndex, temp,
-                                             flags);
+                                             &flags);
                if (status == 0xffffffff)
                        goto error;