Re: [PATCH] usb: core: Prevent null pointer dereference in update_port_device_state

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Thu, Jan 04, 2024 at 03:56:16PM +0530, Udipto Goswami wrote:
> Currently,the function update_port_device_state gets the usb_hub from
> udev->parent by calling usb_hub_to_struct_hub.
> However, in case the actconfig or the maxchild is 0, the usb_hub would
> be NULL and upon further accessing to get port_dev would result in null
> pointer dereference.

Is this true for any real (or fake) hardware?

> 
> Fix this by introducing an if check after the usb_hub is populated.
> 
> Fixes: 83cb2604f641 ("usb: core: add sysfs entry for usb device state")
> Signed-off-by: Udipto Goswami <quic_ugoswami@quicinc.com>

Any specific reason you don't want this backported to the stable kernels
that include the commit you marked this as a fix for?

As my bot says:

- You have marked a patch with a "Fixes:" tag for a commit that is in an
  older released kernel, yet you do not have a cc: stable line in the
  signed-off-by area at all, which means that the patch will not be
  applied to any older kernel releases.  To properly fix this, please
  follow the documented rules in the
  Documentation/process/stable-kernel-rules.rst file for how to resolve
  this.

thanks,

greg k-h