Re: [PATCH] hid: usbhid: Use flag HID_DISCONNECTED when a usb device is removed

[Reyad Attiyat]

The kernel panic happened when the iio sensor hid usb device was
removed. It tries to set the power state by calling hid_hw_request().
This was on kernel 3.16-rc6
https://gist.github.com/soda0289/2ff543d9cfff6f92c360#file-kernel-panic-when-iio-sensor-usb-device-is-removed

On Fri, Jul 25, 2014 at 12:13 AM, Reyad Attiyat <reyad.attiyat@xxxxxxxxx> wrote:
> Set disconnected flag in struct usbhid when a usb device
> is removed. Check for disconnected flag before sending urb
> requests. This prevents a kernel panic when a hid driver calls
> hid_hw_request() after removing a usb device.
>
> Signed-off-by: Reyad Attiyat <reyad.attiyat@xxxxxxxxx>
> ---
>  drivers/hid/usbhid/hid-core.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
> index 7b88f4c..c8fa957 100644
> --- a/drivers/hid/usbhid/hid-core.c
> +++ b/drivers/hid/usbhid/hid-core.c
> @@ -536,7 +536,8 @@ static void __usbhid_submit_report(struct hid_device *hid, struct hid_report *re
>         int head;
>         struct usbhid_device *usbhid = hid->driver_data;
>
> -       if ((hid->quirks & HID_QUIRK_NOGET) && dir == USB_DIR_IN)
> +       if (((hid->quirks & HID_QUIRK_NOGET) && dir == USB_DIR_IN) ||
> +               test_bit(HID_DISCONNECTED, &usbhid->iofl))
>                 return;
>
>         if (usbhid->urbout && dir == USB_DIR_OUT && report->type == HID_OUTPUT_REPORT) {
> @@ -1366,6 +1367,9 @@ static void usbhid_disconnect(struct usb_interface *intf)
>                 return;
>
>         usbhid = hid->driver_data;
> +       spin_lock_irq(&usbhid->lock);   /* Sync with error and led handlers */
> +       set_bit(HID_DISCONNECTED, &usbhid->iofl);
> +       spin_unlock_irq(&usbhid->lock);
>         hid_destroy_device(hid);
>         kfree(usbhid);
>  }
> --
> 1.9.3
>
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