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    Subject[PATCH 4.14 245/267] xhci: make sure interrupts are restored to correct state
    Date
    From: Mathias Nyman <mathias.nyman@linux.intel.com>

    [ Upstream commit bd82873f23c9a6ad834348f8b83f3b6a5bca2c65 ]

    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>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/usb/host/xhci-hub.c | 8 ++++----
    1 file changed, 4 insertions(+), 4 deletions(-)

    diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
    index 997ff183c9cbb..95503bb9b067d 100644
    --- a/drivers/usb/host/xhci-hub.c
    +++ b/drivers/usb/host/xhci-hub.c
    @@ -855,7 +855,7 @@ 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)
    {
    @@ -937,12 +937,12 @@ 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,
    @@ -1090,7 +1090,7 @@ 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;

    --
    2.20.1


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