On Thu, Dec 11, 2014 at 03:02:31PM +0200, Octavian Purdila wrote:
> Without suspend/resume functionality in the USB driver the USB core
> will disconnect and reconnect the DLN2 port and because the GPIO
> framework does not yet support removal of an in-use controller a
> suspend/resume operation will result in a crash.
>
> This patch provides suspend and resume functions for the DLN2 driver
> so that the above scenario is avoided.
>
> Signed-off-by: Octavian Purdila <octavian.purdila@xxxxxxxxx>
> ---
> drivers/mfd/dln2.c | 41 ++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 38 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
> index 6d49685..08c403c 100644
> --- a/drivers/mfd/dln2.c
> +++ b/drivers/mfd/dln2.c
> @@ -587,7 +587,6 @@ static void dln2_free_rx_urbs(struct dln2_dev *dln2)
> int i;
>
> for (i = 0; i < DLN2_MAX_URBS; i++) {
> - usb_kill_urb(dln2->rx_urb[i]);
> usb_free_urb(dln2->rx_urb[i]);
> kfree(dln2->rx_buf[i]);
> }
Now dln2_free will no longer stop the urbs before releasing them and
hence you can get a use after free in the error path of probe where
dln2_free is called after you have submitted the urbs.
Please be more careful.
Splitting allocation and submission (and reuse that helper in resume)
and adding a stop_rx_urbs helper might be a good idea.
> @@ -665,9 +664,8 @@ static const struct mfd_cell dln2_devs[] = {
> },
> };
>
> -static void dln2_disconnect(struct usb_interface *interface)
> +static void dln2_stop(struct dln2_dev *dln2)
> {
> - struct dln2_dev *dln2 = usb_get_intfdata(interface);
> int i, j;
>
> /* don't allow starting new transfers */
> @@ -696,6 +694,16 @@ static void dln2_disconnect(struct usb_interface *interface)
> /* wait for transfers to end */
> wait_event(dln2->disconnect_wq, !dln2->active_transfers);
>
> + for (i = 0; i < DLN2_MAX_URBS; i++)
> + usb_kill_urb(dln2->rx_urb[i]);
> +}
> +
> +static void dln2_disconnect(struct usb_interface *interface)
> +{
> + struct dln2_dev *dln2 = usb_get_intfdata(interface);
> +
> + dln2_stop(dln2);
> +
> mfd_remove_devices(&interface->dev);
>
> dln2_free(dln2);
> @@ -767,11 +775,38 @@ static const struct usb_device_id dln2_table[] = {
>
> MODULE_DEVICE_TABLE(usb, dln2_table);
I believe I already asked you to place the new callbacks above the id
table.
> +static int dln2_suspend(struct usb_interface *iface, pm_message_t message)
> +{
> + struct dln2_dev *dln2 = usb_get_intfdata(iface);
> +
> + dln2_stop(dln2);
> + return 0;
> +}
> +
> +static int dln2_resume(struct usb_interface *iface)
> +{
> + struct dln2_dev *dln2 = usb_get_intfdata(iface);
> + int i;
> + int ret = 0;
> +
> + dln2->disconnect = false;
> +
> + for (i = 0; i < DLN2_MAX_URBS; i++) {
> + ret = usb_submit_urb(dln2->rx_urb[i], GFP_KERNEL);
You cannot use GFP_KERNEL in resume, use GFP_NOIO.
> + if (ret)
Add a dev_err here.
> + break;
> + }
> +
> + return ret;
> +}
Johan
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