Re: [PATCH] usb: roles: try to get/put all relevant modules

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Jan 12, 2024 at 09:24:11AM +0100, Greg KH wrote:
> On Fri, Jan 12, 2024 at 04:01:08PM +0800, Xu Yang wrote:
> > +void usb_role_switch_get_modules(struct device *dev)
> > +{
> > +	while (dev) {
> > +		if (dev->driver)
> > +			WARN_ON(!try_module_get(dev->driver->owner));
> 
> You just crashed all systems that have panic-on-warn enabled, which is
> by far (i.e. in the billions) the huge majority of Linux systems in the
> world.
> 
> If this is something that can fail, then properly handle the issue,
> don't just give up and say "let's fill the kernel log with a mess and
> reboot the box!".

Ah, I see now you are just moving the code, but please, let's fix this
properly, don't persist in the wrong code here.

thanks,

greg k-h