Re: [mm/slub] 3616799128: BUG_kmalloc-#(Not_tainted):kmalloc_Redzone_overwritten

Christoph Lameter
2022-08-01T08:13:11Z

On Mon, 1 Aug 2022, Feng Tang wrote:

> > Or does it make sense to prohibit KASAN+SLUB_DEBUG combination? Does
> > SLUB_DEBUG add anything on top of KASAN?
>
> I did a quick glance, seems the KASAN will select SLUB_DEBUG in
> many cases, as shown in the lib/Kconfig.kasan:
>
> config KASAN_GENERIC
> ...
> select SLUB_DEBUG if SLUB
>
> config KASAN_SW_TAGS
> ...
> select SLUB_DEBUG if SLUB

SLUB_DEBUG is on by default on all distros. This just means that debugging
support is compiled in but not activated. Kasan etc could depend on
SLUB_DEBUG. Without SLUB_DEBUG the debugging infrastructure of SLUB that
is use by Kasan is not included.

If you want to enable debugging on bootup then you need to set
SLUB_DEBUG_ON.