Re: [PATCH 26/26] kasan: rework Kconfig settings

Andrey Ryabinin
2017-03-03T15:08:24Z

On 03/02/2017 07:38 PM, Arnd Bergmann wrote:

>
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 97d62c2da6c2..27c838c40a36 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -216,10 +216,9 @@ config ENABLE_MUST_CHECK
> config FRAME_WARN
> int "Warn for stack frames larger than (needs gcc 4.4)"
> range 0 8192
> - default 0 if KASAN
> - default 2048 if GCC_PLUGIN_LATENT_ENTROPY
> + default 3072 if KASAN_EXTRA
> default 1024 if !64BIT
> - default 2048 if 64BIT
> + default 1280 if 64BIT

This looks unrelated. Also, it means that now we have 1280 with KASAN=y && KASAN_EXTRA=n.
Judging from changelog I assume that this hunk slipped here from the follow up series.

> help
> Tell gcc to warn at build time for stack frames larger than this.
> Setting this too low will cause a lot of warnings.
> @@ -499,7 +498,7 @@ config DEBUG_OBJECTS_ENABLE_DEFAULT
>
> config DEBUG_SLAB
> bool "Debug slab memory allocations"
> - depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
> + depends on DEBUG_KERNEL && SLAB && !KMEMCHECK && !KASAN
> help
> Say Y here to have the kernel do limited verification on memory
> allocation as well as poisoning memory on free to catch use of freed
> @@ -511,7 +510,7 @@ config DEBUG_SLAB_LEAK
>
> config SLUB_DEBUG_ON
> bool "SLUB debugging on by default"
> - depends on SLUB && SLUB_DEBUG && !KMEMCHECK
> + depends on SLUB && SLUB_DEBUG && !KMEMCHECK && !KASAN

Why? SLUB_DEBUG_ON works with KASAN.

> default n
> help
> Boot with debugging on by default. SLUB boots by default with