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From:   "=?ISO-8859-15?B?/YCAgISB?=" <jbi.octave@gmail.com>
Date:   Fri, 5 Jun 2020 08:42:35 +0100 (BST)
To:     Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
cc:     Steven Rostedt <rostedt@goodmis.org>,
        Jules Irenge <jbi.octave@gmail.com>,
        linux-kernel@vger.kernel.org, tglx@linutronix.de,
        paulmck@kernel.org, mingo@redhat.com, boqun.feng@gmail.com,
        Borislav Petkov <bp@alien8.de>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 4/5] x86/ftrace: Add annotations for ftrace_arch_code_modify_prepare()
 and ftrace_arch_code_modify_post_process()
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On Wed, 3 Jun 2020, Luc Van Oostenryck wrote:

> On Mon, Jun 01, 2020 at 03:46:47PM -0400, Steven Rostedt wrote:
>> On Mon,  1 Jun 2020 19:45:51 +0100
>> Jules Irenge <jbi.octave@gmail.com> wrote:
>>
>>> Sparse reports warnings
>>>
>>> warning: context imbalance in ftrace_arch_code_modify_prepare()
>>> 	- wrong count at exit
>>> warning: context imbalance in ftrace_arch_code_modify_post_process()
>>> 	- wrong count at exit
>>>
>>> The root cause is that even if
>>>  the annotations on the function are correct,
>>> mutex do not support annotation
>
> Yes.
>
>> Wait what? This looks like either a bug in sparse, or we just remove the
>> annotations. This just makes the code ugly, and looks silly.
>
> The annotations added by commit
>  074376ac0e1d ("ftrace/x86: Anotate text_mutex split between ...
> are indeed wrong (because they don't match what the functions are
> really doing / mutex operations have never been annotated).
> The're also pointless since their prototypes are un-annotated.

Interesting, I would think the best way would then be to remove the 
annotations. There are quite a number of them.

I will have to investigate more on mutex and annotation before moving 
forward.

Thanks for feedback.

Jules