On 09/28/2010 04:12 PM, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@xxxxxxx>
>
> On x86_64 the configuration and version of the kernel that
> hibernates and creates a system image may be different from the
> configuration and version of the boot kernel that loads the image.
> So long as both these kernels are built with the same value of
> RESTORE_MAGIC, the image created by one of them should be
> successfully loaded and restored by the other one.
>
> It wasn't necessary to modify RESTORE_MAGIC in the past, but now
> that we are adding compression to the in-kernel hibernate code,
> change the value of RESTORE_MAGIC so that earlier kernels don't
> try to load compressed images they can't handle.
>
> Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
> ---
> arch/x86/power/hibernate_64.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: linux-2.6/arch/x86/power/hibernate_64.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/power/hibernate_64.c
> +++ linux-2.6/arch/x86/power/hibernate_64.c
> @@ -137,7 +137,7 @@ struct restore_data_record {
> unsigned long magic;
> };
>
> -#define RESTORE_MAGIC 0x0123456789ABCDEFUL
> +#define RESTORE_MAGIC 0x0123456789ABCDF0UL
>
Two issues with this:
a) shouldn't we only set this when the image is actually compressed?
b) using systematic magics like this is pessimal in terms of collision
avoidance. It's much better to use a true random number.
Hence, I propose:
: anacreon 95 ; ranpwd -xc 16
0x4ddedd3236f1e6e1
-hpa
_______________________________________________
linux-pm mailing list
linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linux-foundation.org/mailman/listinfo/linux-pm
