Re: [PATCH] Fix new alloc_bootmem_core (Re: [PATCH -mm 08/14] bootmem: clean up alloc_bootmem_core)

[Johannes Weiner]

Hi,

Yasunori Goto <y-goto@xxxxxxxxxxxxxx> writes:

> Hi Johannes-san.
>
> I found a bug in this patch.
>
>
>> -	eidx = end_pfn - PFN_DOWN(node_boot_start);
>> +	if (goal && goal < max)
>> +		start = ALIGN(goal, step);
>> +	else
>> +		start = ALIGN(min, step);
>
> Here should check (min < goal) too.
>
> If not, start can becomes smaller than min. and sidx doesn't point
> correct index.
> alloc_bootmem_node() almost allocates pages of other node,
> when node's min address is over MAX_DMA_ADDRESS.

Oh, good catch!

> Bye.
>
> ----
>
> Fix new alloc_bootmem_core() of bootmem-clean-up-alloc_bootmem_core.patch
> in 2.6.26-rc5-mm3.
>
> (min < goal) should be checked too.
>
>
> Signed-off-by: Yasunori Goto <y-goto@xxxxxxxxxxxxxx>
> CC: Johannes Weiner <hannes@xxxxxxxxxxxx>
  Acked-by: Johannes Weiner <hannes@xxxxxxxxxxxx>

> ---
>  mm/bootmem.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: current/mm/bootmem.c
> ===================================================================
> --- current.orig/mm/bootmem.c	2008-06-17 18:33:31.000000000 +0900
> +++ current/mm/bootmem.c	2008-06-17 18:34:27.000000000 +0900
> @@ -435,7 +435,7 @@
>  
>  	step = max(align >> PAGE_SHIFT, 1UL);
>  
> -	if (goal && goal < max)
> +	if (goal && min < goal && goal < max)
>  		start = ALIGN(goal, step);
>  	else
>  		start = ALIGN(min, step);

	Hannes
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