[RFT] Revert "lockdep: Enable PROVE_RAW_LOCK_NESTING with PROVE_LOCKING."

[Luca Coelho]

Oops, I intended to send this to trybot and intel-xe (not intel-gfx),
sorry.  But now it's too late and if I send it there, we will just use
more resources.

--
Cheers,
Luca.


On Mon, 2024-12-09 at 15:53 +0200, Luca Coelho wrote:
> This reverts commit 560af5dc839eef08a273908f390cfefefb82aa04.
> 
> Signed-off-by: Luca Coelho <luciano.coelho at intel.com>
> ---
> 
> It seems that we have a few issues with this configuration in xe and
> in i915.  Let's try to revert it to see if the problems we're seeing
> go away.
> 
> Note, these are _real_ issues, but only if CONFIG_RT is enabled, so the actual issues need to be solved properly, but we can revert this change until then, to avoid regressions.
> 
> 
>  lib/Kconfig.debug | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index f3d723705879..de4ffe09323b 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1397,14 +1397,22 @@ config PROVE_LOCKING
>  	 For more details, see Documentation/locking/lockdep-design.rst.
>  
>  config PROVE_RAW_LOCK_NESTING
> -	bool
> +	bool "Enable raw_spinlock - spinlock nesting checks"
>  	depends on PROVE_LOCKING
> -	default y
> +	default n
>  	help
>  	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
>  	 that the lock nesting rules for PREEMPT_RT enabled kernels are
>  	 not violated.
>  
> +	 NOTE: There are known nesting problems. So if you enable this
> +	 option expect lockdep splats until these problems have been fully
> +	 addressed which is work in progress. This config switch allows to
> +	 identify and analyze these problems. It will be removed and the
> +	 check permanently enabled once the main issues have been fixed.
> +
> +	 If unsure, select N.
> +
>  config LOCK_STAT
>  	bool "Lock usage statistics"
>  	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT