From: John Ogness <john.ogness@linutronix.de>
To: Borislav Petkov <bp@alien8.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/microcode: move @microcode_mutex definition near usage
Date: Fri, 24 Mar 2023 14:17:10 +0106 [thread overview]
Message-ID: <87edpenvkh.fsf@jogness.linutronix.de> (raw)
In-Reply-To: <20230324120019.GAZB2Q09ODVq0iYz5l@fat_crate.local>
On 2023-03-24, Borislav Petkov <bp@alien8.de> wrote:
>> If CONFIG_MICROCODE_LATE_LOADING is not enabled, the compiler warns:
>>
>> 'microcode_mutex' defined but not used
>
> How do you trigger this?
I was doing some tests with CONFIG_PREEMPT_RT. I did not think that
mattered, since the mutex is obviously defined but not used for
!CONFIG_MICROCODE_LATE_LOADING.
Digging deeper I see that initializing @wait_list in
__MUTEX_INITIALIZER() is what is allowing unused global mutexes to go
unnoticed. Since with CONFIG_PREEMPT_RT the mutex is different and
initialized differently, it is (correctly) detected as unused.
CONFIG_PREEMPT_RT cannot be enabled yet, so this patch is not urgent for
mainline. But at some point it will need fixing.
John Ogness
next prev parent reply other threads:[~2023-03-24 13:12 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-24 11:47 [PATCH] x86/microcode: move @microcode_mutex definition near usage John Ogness
2023-03-24 12:00 ` Borislav Petkov
2023-03-24 13:11 ` John Ogness [this message]
2023-03-24 15:19 ` Borislav Petkov
2023-03-24 16:33 ` John Ogness
2023-03-24 16:44 ` Borislav Petkov
2023-07-12 14:09 ` John B. Wyatt IV
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