Re: [PATCH v1 1/2] staging: gdm724x: fix type confusion in gdm_lte_event_rcv()

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Jul 03, 2025 at 03:03:46PM +0800, Lin Ma wrote:
> Hello Greg,
> 
> > > ```
> > > 
> > > - by `dev->type`. See ax25_device_event()
> > > ```
> > > static int ax25_device_event(struct notifier_block *this, unsigned long event,
> > >                  void *ptr)
> > > {
> > >     struct net_device *dev = netdev_notifier_info_to_dev(ptr);
> > > 
> > >     ......
> > > 
> > >     /* Reject non AX.25 devices */
> > >     if (dev->type != ARPHRD_AX25)
> > >         return NOTIFY_DONE;
> > > ```
> > 
> > 
> > Those are core functions that all drivers are using, and the "type" of
> > device is also ok to look at.  You are trying to compare a specific
> > callback in this change, which feels wrong to me.
> 
> Got it. I will try to prepare another version.
> 
> > 
> > Wait, what tree are you making this change against?  I don't even see
> > the file you are trying to patch in the latest tree, are you sure it's
> > not just deleted already?
> > 
> > ...
> > 
> > Again, make sure this file is still present in the tree before going
> > further :)
> > 
> > thanks,
> > 
> > greg k-h
> 
> Yes, you are right, just like how I pointed out in the patch:
> 
> """
> This bug was "fixed" in upstream kernel by the commit 1c2d364e7f7f
> ("staging: gdm724x: Remove unused driver"). However, other stable
> versions still contain it. Fix the confusion bug by adding checks.
> """
> 
> That is, together with another identified bug, has already been deleted the
> latest upstream kernel. (see https://lore.kernel.org/lkml/20250703052837.15458-1-linma@zju.edu.cn/T/#u)

That email was not threaded, and also not obvious what was going on, so
I long deleted it from my review queue.

> I sent this patch just because the stable version, like 5.15.186, still
> contains it. T.T

Ah, that was not obvious at all.  Remember, some of us get thousands of
emails a day to review, please make things that you are submitting for
non-mainline kernels very very very obvious as to what is going on.

> Therefore, shall I proceed with the patches? Or maybe the stable tree
> could also delete that vulnerable code?

For a staging driver, it's not an issue, don't worry about it, no distro
should be using it anyway as no one has the hardware :)

thanks,

greg k-h