Re: PATCH default C1

[Janosch Machowinski <scotch-cGBD8117FJM@public.gmane.org>]

Dominik Brodowski schrieb:
> Hi,
> 
> 
> On Fri, Sep 16, 2005 at 09:03:36PM +0200, Janosch Machowinski wrote:
> 
>>@@ -678,6 +669,13 @@
>> 
>> 		(pr->power.count)++;
>> 		memcpy(&(pr->power.states[pr->power.count]), &cx, sizeof(cx));
>>+
>>+		/* We support up to ACPI_PROCESSOR_MAX_POWER. */
>>+		if (pr->power.count >= ACPI_PROCESSOR_MAX_POWER) {
>>+		        printk(KERN_WARNING "Limiting number of power states to max (%d)\n", ACPI_PROCESSOR_MAX_POWER);
>>+			printk(KERN_WARNING "Please increase ACPI_PROCESSOR_MAX_POWER if needed.\n");
>>+			break;
>>+		}
> 
> 
> 
> Memory corruption: If pr->power.count is ACPI_PROCESSOR_MAX_POWER (or
> larger), pr->power.states[pr->power.count] is pointing to an invalid memory
> address. Therefore, the check needs to stay at the place it was before.
> 
Hu ?
I think teh check is just right where I placed it...
Following case :
A CST contains 9 C-states,
MAX_POWER = 8.
One C-State is invallid (not the last one)
In this case we would only detect 7 C-states (with the check in old place)
pr->power.count tells us how many C-States where actually discovered, 
that's why I moved the check.

But you're right, it runs out of the array...
what about ?
Is there a nicer way to do this ?
+		if (pr->power.count >= (ACPI_PROCESSOR_MAX_POWER -1)) {

    Janosch


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