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Subject[PATCH 5.4 032/177] xhci: make sure interrupts are restored to correct state
Date
From: Mathias Nyman <mathias.nyman@linux.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@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>

---
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;


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