Re: [PATCH 2/2] slab, kmemleak, bugfix, pass the correct pointerto kmemleak_erase()

[Pekka Enberg]

Catalin Marinas wrote:
> "J. R. Okajima" <hooanon05@xxxxxxxxxxx> wrote:
> > In ____cache_alloc(), the variable 'ac' may be changed after
> > cache_alloc_refill() and the following kmemleak_erase() may get an
> > incorrect pointer.
> > Update 'ac' after cache_alloc_refill() unconditionally.
> > cf. http://marc.info/?l=linux-kernel&m=125873373124187&w=2
> >     and its thread.
> >
> > Cc: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> >
> > Signed-off-by: J. R. Okajima <hooanon05@xxxxxxxxxxx>
> > ---
> >  mm/slab.c |    5 +++++
> >  1 files changed, 5 insertions(+), 0 deletions(-)
> >
> > diff --git a/mm/slab.c b/mm/slab.c
> > index 4e61449..66e9047 100644
> > --- a/mm/slab.c
> > +++ b/mm/slab.c
> > @@ -3103,6 +3103,11 @@ static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
> >  	} else {
> >  		STATS_INC_ALLOCMISS(cachep);
> >  		objp = cache_alloc_refill(cachep, flags);
> > +		/*
> > +		 * the 'ac' may be updated by cache_alloc_refill(),
> > +		 * and kmemleak_erase() requires its correct value.
> > +		 */
> > +		ac = cpu_cache_get(cachep);
> >  	}
> >  	/*
> >  	 * To avoid a false negative, if an object that is in one of the
>
> Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
>
> Thanks.

Applied, thanks!
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