Re: [RFC][PATCH 1/5] mm/slab_common: allow NULL cache pointer in kmem_cache_destroy()

From: David Rientjes
Date: Wed Jun 17 2015 - 19:15:17 EST


On Tue, 9 Jun 2015, Sergey Senozhatsky wrote:

> kmem_cache_destroy() does not tolerate a NULL kmem_cache pointer
> argument and performs a NULL-pointer dereference. This requires
> additional attention and effort from developers/reviewers and
> forces all kmem_cache_destroy() callers (200+ as of 4.1) to do
> a NULL check
>
> if (cache)
> kmem_cache_destroy(cache);
>
> Or, otherwise, be invalid kmem_cache_destroy() users.
>
> Tweak kmem_cache_destroy() and NULL-check the pointer there.
>
> Proposed by Andrew Morton.
>
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> Reported-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> LKML-reference: https://lkml.org/lkml/2015/6/8/583

Acked-by: David Rientjes <rientjes@xxxxxxxxxx>

kmem_cache_destroy() isn't a fastpath, this is long overdue. Now where's
the patch to remove the NULL checks from the callers? ;)
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