linux-kernel - [PATCH 5.4 032/177] xhci: make sure interrupts are restored to correct state

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Date:   Mon, 16 Dec 2019 18:48:08 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Mathias Nyman <mathias.nyman@...ux.intel.com>
Subject: [PATCH 5.4 032/177] xhci: make sure interrupts are restored to correct state

From: Mathias Nyman <mathias.nyman@...ux.intel.com>

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.

Cc: <stable@...r.kernel.org> # v3.12+
Fixes: 8b3d45705e54 ("usb: Fix xHCI host issues on remote wakeup.")
Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>
Link: https://lore.kernel.org/r/20191211142007.8847-7-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/usb/host/xhci-hub.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- 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(stru
 
 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_re
 		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(st
 }
 
 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(st
 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
 		}
 		trace_xhci_get_port_status(wIndex, temp);
 		status = xhci_get_port_status(hcd, bus_state, wIndex, temp,
-					      flags);
+					      &flags);
 		if (status == 0xffffffff)
 			goto error;