Re: [PATCH] mm/slub: do not place freelist pointer to middle of object if redzone is on

[Kees Cook]

On Sat, Apr 25, 2020 at 05:13:38PM +0800, Changbin Du wrote:
> The recent kernel fails to boot when slub redzone is turned on. This is
> caused by commit 3202fa62fb ("slub: relocate freelist pointer to middle of
> object") which relocates freelist pointer to middle of object. In this
> case, get_track() gets a wrong address and then the redzone is overwritten.

Hi! A fix for this is already in -next:

https://www.ozlabs.org/~akpm/mmotm/broken-out/slub-avoid-redzone-when-choosing-freepointer-location.patch

the above doesn't disable the mitigation when using redzones, so I
prefer that to this suggested solution.

-- 
Kees Cook