Re: [PATCH] check that acpi_wakeup_address is below 1MB

[Ingo Molnar <mingo@elte.hu>]

* matthieu castet <castet.matthieu@free.fr> wrote:

> Hi,
>
> this patch had a check that the memory allocated is in the first 1MB.
> The check is similar to the one in smp_alloc_memory.
>
>
> Signed-off-by: "Matthieu CASTET <castet.matthieu@free.fr>"

> diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
> index 6bc815c..65ab23c 100644
> --- a/arch/x86/kernel/acpi/sleep.c
> +++ b/arch/x86/kernel/acpi/sleep.c
> @@ -65,6 +65,10 @@ void __init acpi_reserve_bootmem(void)
>  	acpi_wakeup_address = (unsigned long)alloc_bootmem_low(PAGE_SIZE*2);
>  	if (!acpi_wakeup_address)
>  		printk(KERN_ERR "ACPI: Cannot allocate lowmem, S3 disabled.\n");
> +
> +	/* check if we are in first 1MB of memory */
> +	if (__pa(acpi_wakeup_address) >= 1024*1024-PAGE_SIZE*2)
> +		BUG();

please never BUG() out unless totally unavoidable - especially in such 
early bootup code - that might prevent people from being able to report 
anything beyond 'my bootup hung'.

print a WARN_ON() (that way kerneloops.org can pick it up), and perhaps 
disable ACPI sleep functionality. BUG()-ing out is way too drastic and 
way too user-unfriendly.

	Ingo