Re: [PATCH] x86/resctrl: Fix potential lockdep warning

Xiaochen Shen
2019-11-19T07:44:52Z

On 11/18/2019 23:02, Borislav Petkov wrote:
> On Sun, Nov 17, 2019 at 12:13:20AM +0800, Xiaochen Shen wrote:
>> Actually this fix covers all the cases of an audit of the calling paths
>> of rdt_last_cmd_{clear,puts,printf}(), to make sure we only have the
>> lockdep_assert_held() in places where we are sure that it must be held.
>
> That's kinda what I suggested, isn't it?
>
> All I meant was, not to have a
>
> rdtgroup_kn_lock_live()
>
> call in the code as this function does *not* unconditionally grab the
> rdtgroup_mutex. And then call a function which unconditionally checks
> whether the mutex is held.
>

Hi Boris,

Thank you for your good suggestion. I will try to follow up if we could
improve the code in call sites of rdtgroup_kn_lock_live() in separate patch.

In my opinion, the potential lockdep issues in all call sites of
rdt_last_cmd_{clear,puts,...}() have been fixed in this patch.

Thank you.

--
Best regards,
Xiaochen