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Date: Tue, 15 May 2007 16:33:21 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Christoph Lameter <clameter@sgi.com>
Cc: mroos@linux.ee, David Miller <davem@davemloft.net>,
       sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: slab hang on boot
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On Mon, 14 May 2007 16:46:17 -0700 (PDT)
Christoph Lameter <clameter@sgi.com> wrote:

> @@ -86,6 +87,9 @@ static inline int kmalloc_index(int size
>  	 */
>  	WARN_ON_ONCE(size == 0);
>  
> +	if (size >= (1UL << KMALLOC_SHIFT_HIGH))
> +		return -1;
> +

I don't quite understand why we did this.  The subsequent logic in
kmalloc_index() should return -1 for this `size' anyway.  If it doesn't,
it's bust, isn't it?

Also, afaict kmalloc_slab() will totally mishandle the -1 return value and
will return a garbage kmem_cache*, via

        return &kmalloc_caches[index];


Could you double-check it all please?