Re: [PATCH 4.0+] cpufreq: Use struct kobj_attribute instead of struct global_attr

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Mar 07, 2019 at 04:53:33PM +0530, Viresh Kumar wrote:
> commit 625c85a62cb7d3c79f6e16de3cfa972033658250 upstream.
> 
> The cpufreq_global_kobject is created using kobject_create_and_add()
> helper, which assigns the kobj_type as dynamic_kobj_ktype and show/store
> routines are set to kobj_attr_show() and kobj_attr_store().
> 
> These routines pass struct kobj_attribute as an argument to the
> show/store callbacks. But all the cpufreq files created using the
> cpufreq_global_kobject expect the argument to be of type struct
> attribute. Things work fine currently as no one accesses the "attr"
> argument. We may not see issues even if the argument is used, as struct
> kobj_attribute has struct attribute as its first element and so they
> will both get same address.
> 
> But this is logically incorrect and we should rather use struct
> kobj_attribute instead of struct global_attr in the cpufreq core and
> drivers and the show/store callbacks should take struct kobj_attribute
> as argument instead.
> 
> This bug is caught using CFI CLANG builds in android kernel which
> catches mismatch in function prototypes for such callbacks.
> 
> Cc: 4.0+ <stable@vger.kernel.org> # 4.0+
> Reported-by: Donghee Han <dh.han@samsung.com>
> Reported-by: Sangkyu Kim <skwith.kim@samsung.com>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
> This needs to be applied from v4.0 to v4.5 (including both).

Does not apply to 4.4.y either :(

greg k-h