Re: [PATCH v2 1/1] usb: xhci: fix return value of xhci_setup_device()

From: Lu Baolu
Date: Thu Sep 08 2016 - 03:29:35 EST

Hi Greg,

On 09/08/2016 02:38 PM, Greg KH wrote:
> On Thu, Sep 08, 2016 at 08:41:02AM +0800, Lu Baolu wrote:
>> xhci_setup_device() should return failure with correct error number
>> when xhci host has died, removed or halted.
>> Cc: stable@xxxxxxxxxxxxxxx # 4.3+
> Why is this a stable kernel issue? What bug does it fix that affects
> users?

During usb device enumeration, if xhci host is not accessible (died,
removed or halted), the hc_driver->address_device() should return
a corresponding error code to usb core. But current xhci driver just
returns success. This will mislead usb core to continue enumeration:
reading device descriptor, which will result in failure, and users will
get a misleading message like "device descriptor read/8, error -110".

Best regards,
Lu Baolu