Re: [PATCH] tracing/timerlat: move interface_lock definition up

[Steven Rostedt]

On Mon,  9 Sep 2024 13:53:20 +0000
Arnd Bergmann <arnd@xxxxxxxxxx> wrote:

> From: Arnd Bergmann <arnd@xxxxxxxx>
> 
> The definition was previously moved into an #ifdef block by
> accident and now causes a build failure when CONFIG_TIMERLAT_TRACER
> is disabled:
> 
> In file included from include/linux/seqlock.h:19,
>                  from kernel/trace/trace_osnoise.c:20:
> kernel/trace/trace_osnoise.c: In function 'osnoise_sleep':
> kernel/trace/trace_osnoise.c:1631:21: error: 'interface_lock' undeclared (first use in this function); did you mean 'trace_clock'?
>  1631 |         mutex_lock(&interface_lock);
>       |                     ^~~~~~~~~~~~~~
> 
> Move it up some more to be outside of that #ifdef again.

Thanks, but for some reason I never got your email. I only noticed this
from Patchwork, and I'm replying via lore.

I also fixed it due to someone else reporting the bug. I'm currently
running mine through my tests, although it is the exact same change as yours.

  https://lore.kernel.org/linux-trace-kernel/20240909103231.23a289e2@xxxxxxxxxxxxxxxxxx/

-- Steve


> 
> Fixes: e6a53481da29 ("tracing/timerlat: Only clear timer if a kthread exists")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> It looks like the regression already made it into 6.11-rc7 as
> part of
> https://lore.kernel.org/lkml/20240905172827.6a64cf97@xxxxxxxxxxxxxxxxxx/
> so this fixup (if correct) is needed for 6.11 as well
> ---
>  kernel/trace/trace_osnoise.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
> index 20c6660762a3..acfd57689af6 100644
> --- a/kernel/trace/trace_osnoise.c
> +++ b/kernel/trace/trace_osnoise.c
> @@ -228,6 +228,11 @@ static inline struct osnoise_variables *this_cpu_osn_var(void)
>  	return this_cpu_ptr(&per_cpu_osnoise_var);
>  }
>  
> +/*
> + * Protect the interface.
> + */
> +static struct mutex interface_lock;
> +
>  #ifdef CONFIG_TIMERLAT_TRACER
>  /*
>   * Runtime information for the timer mode.
> @@ -252,11 +257,6 @@ static inline struct timerlat_variables *this_cpu_tmr_var(void)
>  	return this_cpu_ptr(&per_cpu_timerlat_var);
>  }
>  
> -/*
> - * Protect the interface.
> - */
> -static struct mutex interface_lock;
> -
>  /*
>   * tlat_var_reset - Reset the values of the given timerlat_variables
>   */