[PATCH v2] ARM: exynos_defconfig: Enable CONFIG_LOCKUP_DETECTOR

Anand Moon moon.linux at yahoo.com
Wed Jan 7 05:56:36 PST 2015


Hi Kszysztof Kozlowski,

I picked up the bellow line from 


Documentation/locking/lockdep-design.txt  line no 18

I understand that by enabling this flag we could detect possible 

deadlock situation with the kernel. Sorry for the noise.


-Anand Moon



On Wednesday, January 7, 2015 6:57 PM, Krzysztof Kozlowski <k.kozlowski at samsung.com> wrote:
On śro, 2015-01-07 at 18:29 +0530, Anand Moon wrote:
> Enable CONFIG_LOCKUP_DETECTOR to validate kernel locks state for exynos SOC.
> 
> Enabling CONFIG_LOCKUP_DETECTOR help validator tracks the 'state' of lock-classes,
> and it tracks dependencies between different lock-classes.
> The validator maintains a rolling proof that the state and
> the dependencies are correct.

Unfortunately this is not correct. Lockup detector does something else.
Please read the help/manual for LOCKUP_DETECTOR. You can find in
lib/Kconfig.debug (around line 667).

Best regards,
Krzysztof

> 
> Changes since v2:
>  * Made commit message more clear
>  * Corrected grammer in code comment
> 
> Tested on Exynos5422 ODROID XU3 board.
> 
> Signed-off-by: Anand Moon <moon.linux at yahoo.com>
> Reviewed-by: Krzysztof Kozlowski <k.kozlowski at samsung.com>
> ---
>  arch/arm/configs/exynos_defconfig | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/arm/configs/exynos_defconfig b/arch/arm/configs/exynos_defconfig
> index 5ef14de..ecd9987 100644
> --- a/arch/arm/configs/exynos_defconfig
> +++ b/arch/arm/configs/exynos_defconfig
> @@ -178,6 +178,7 @@ CONFIG_PRINTK_TIME=y
>  CONFIG_DEBUG_FS=y
>  CONFIG_MAGIC_SYSRQ=y
>  CONFIG_DEBUG_KERNEL=y
> +CONFIG_LOCKUP_DETECTOR=y
>  CONFIG_DETECT_HUNG_TASK=y
>  CONFIG_DEBUG_RT_MUTEXES=y
>  CONFIG_DEBUG_SPINLOCK=y



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