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    Subject[34-longterm 252/260] USB: disable endpoints after unbinding interfaces, not before
    Date
    From: Alan Stern <stern@rowland.harvard.edu>

    commit 80f0cf3947889014d3a3dc0ad60fb87cfda4b12a upstream.

    This patch (as1430) fixes a bug in usbcore. When a device
    configuration change occurs or a device is removed, the endpoints for
    the old config should be completely disabled. However it turns out
    they aren't; this is because usb_unbind_interface() calls
    usb_enable_interface() or usb_set_interface() to put interfaces back
    in altsetting 0, which re-enables the interfaces' endpoints.

    As a result, when a device goes through a config change or is
    unconfigured, the ep_in[] and ep_out[] arrays may be left holding old
    pointers to usb_host_endpoint structures. If the device is
    deauthorized these structures get freed, and the stale pointers cause
    errors when the the device is eventually unplugged.

    The solution is to disable the endpoints after unbinding the
    interfaces instead of before. This isn't as large a change as it
    sounds, since usb_unbind_interface() disables all the interface's
    endpoints anyway before calling the driver's disconnect routine,
    unless the driver claims to support "soft" unbind.

    This fixes Bugzilla #19192. Thanks to "Tom" Lei Ming for diagnosing
    the underlying cause of the problem.

    Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
    Tested-by: Carsten Sommer <carsten_sommer@ymail.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
    Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
    ---
    drivers/usb/core/message.c | 14 +++++++-------
    1 files changed, 7 insertions(+), 7 deletions(-)

    diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
    index ad1f359..559deec 100644
    --- a/drivers/usb/core/message.c
    +++ b/drivers/usb/core/message.c
    @@ -1155,13 +1155,6 @@ void usb_disable_device(struct usb_device *dev, int skip_ep0)
    {
    int i;

    - dev_dbg(&dev->dev, "%s nuking %s URBs\n", __func__,
    - skip_ep0 ? "non-ep0" : "all");
    - for (i = skip_ep0; i < 16; ++i) {
    - usb_disable_endpoint(dev, i, true);
    - usb_disable_endpoint(dev, i + USB_DIR_IN, true);
    - }
    -
    /* getting rid of interfaces will disconnect
    * any drivers bound to them (a key side effect)
    */
    @@ -1191,6 +1184,13 @@ void usb_disable_device(struct usb_device *dev, int skip_ep0)
    if (dev->state == USB_STATE_CONFIGURED)
    usb_set_device_state(dev, USB_STATE_ADDRESS);
    }
    +
    + dev_dbg(&dev->dev, "%s nuking %s URBs\n", __func__,
    + skip_ep0 ? "non-ep0" : "all");
    + for (i = skip_ep0; i < 16; ++i) {
    + usb_disable_endpoint(dev, i, true);
    + usb_disable_endpoint(dev, i + USB_DIR_IN, true);
    + }
    }

    /**
    --
    1.7.3.3


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