Re: [PATCH] acpi: Fix potential call to a freed memory section.

[Andrew Morton <akpm@linux-foundation.org>]

On Wed, 16 May 2007 09:09:11 -0700 Aaron Durbin <adurbin@google.com> wrote:

> Strip __cpuinit[data] from Node <-> PXM routines and supporting data structures.
> Also make pxm_to_node_map and node_to_pxm_map local to the numa acpi module.
> 
> This fixes a bug triggered by the following conditions:
> - boot on a machine with a SLIT table defined
> - kernel is configured w/ CONFIG_HOTPLUG_CPU=n
> - cat /sys/devices/system/node/node*/distance
> This will cause an oops by calling into a freed memory section.
> 
> In particular, on x86_64, __node_distance calls node_to_pxm().
> 

Yeah, those section warnings we get aren't just noise.

I think this patch is also needed in 2.6.21.x, yes?

> ---
> 
> diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
> index 8fcd6a1..a2efae8 100644
> --- a/drivers/acpi/numa.c
> +++ b/drivers/acpi/numa.c
> @@ -40,19 +40,19 @@ #define PXM_INVAL	-1
>  #define NID_INVAL	-1
>  
>  /* maps to convert between proximity domain and logical node ID */
> -int __cpuinitdata pxm_to_node_map[MAX_PXM_DOMAINS]
> +static int pxm_to_node_map[MAX_PXM_DOMAINS]
>  				= { [0 ... MAX_PXM_DOMAINS - 1] = NID_INVAL };
> -int __cpuinitdata node_to_pxm_map[MAX_NUMNODES]
> +static int node_to_pxm_map[MAX_NUMNODES]
>  				= { [0 ... MAX_NUMNODES - 1] = PXM_INVAL };
>  
> -int __cpuinit pxm_to_node(int pxm)
> +int pxm_to_node(int pxm)
>  {
>  	if (pxm < 0)
>  		return NID_INVAL;
>  	return pxm_to_node_map[pxm];
>  }
>  
> -int __cpuinit node_to_pxm(int node)
> +int node_to_pxm(int node)
>  {
>  	if (node < 0)
>  		return PXM_INVAL;
> diff --git a/include/acpi/acpi_numa.h b/include/acpi/acpi_numa.h
> index f9d2bde..b62cd36 100644
> --- a/include/acpi/acpi_numa.h
> +++ b/include/acpi/acpi_numa.h
> @@ -11,11 +11,8 @@ #else
>  #define MAX_PXM_DOMAINS (256)	/* Old pxm spec is defined 8 bit */
>  #endif
>  
> -extern int __cpuinitdata pxm_to_node_map[MAX_PXM_DOMAINS];
> -extern int __cpuinitdata node_to_pxm_map[MAX_NUMNODES];
> -
> -extern int __cpuinit pxm_to_node(int);
> -extern int __cpuinit node_to_pxm(int);
> +extern int pxm_to_node(int);
> +extern int node_to_pxm(int);
>  extern int __cpuinit acpi_map_pxm_to_node(int);
>  extern void __cpuinit acpi_unmap_pxm_to_node(int);
>  

Moving from __fooinit into .text is always safe.  Len, do you want me to
merge this up?