Messages in this thread | | | From | John Ogness <> | Subject | Re: [PATCH] x86/microcode: move @microcode_mutex definition near usage | Date | Fri, 24 Mar 2023 14:17:10 +0106 |
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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
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