Re: [RFC PATCH v3 4/4] tests/drv_module_reload: add ipvr support

On Fri, Nov 21, 2014 at 09:27:04PM +0100, Thierry Reding wrote:

On Sat, Nov 22, 2014 at 03:10:01AM +0800, Yao Cheng wrote:

...

on vlv, if ipvr is installed, it need be manually unloaded before i915, otherwise user might run into use-after-free issue.

Huh? That doesn't sound right. What exactly is it that's going wrong? You should never have to do this. If you do you're almost certainly doing something wrong in the kernel module.

It's the hilarity called platform devices. Removing them is somewhat racy, so doing that upfront makes the entire thing a bit safer. The use after free is on the text, since grabbing a module refcount for the platform device doesn't work (it would pin the module forever). -Daniel