Re: [Bug #13780] NULL pointer dereference loading powernowk8

[David Rientjes]

On Thu, 10 Sep 2009, Rafael J. Wysocki wrote:

> > So I did a biset, and this is the result:
> > $ git bisect good
> > 0e64a0c982c06a6b8f5e2a7f29eb108fdf257b2f is first bad commit
> > commit 0e64a0c982c06a6b8f5e2a7f29eb108fdf257b2f
> > Author: Dave Jones <davej@xxxxxxxxxx>
> > Date:   Wed Feb 4 14:37:50 2009 -0500
> > 
> >     [CPUFREQ] checkpatch cleanups for powernow-k8
> > 
> >     This driver has so many long function names, and deep nested if's
> >     The remaining warnings will need some code restructuring to clean up.
> > 
> >     Signed-off-by: Dave Jones <davej@xxxxxxxxxx>
> > 
> > :040000 040000 45d8e325663e62e0833cf4e1cb8b27fa4a9b3a56 affb6fab44cb22aca8a33ca0d767797831fc2bae M      arch
> > 
> > 2.6.29-rc5 is good, -rc7 is bad.
> 
> Thanks for the update and for doing the bisection.
> 

0e64a0c has this cleanup, which isn't equivalent to the previous code:

@@ -779,11 +834,12 @@ static int powernow_k8_cpu_init_acpi(struct powernow_k8_data *data)
 		goto err_out;
 	}
 
-	if ((data->acpi_data.control_register.space_id != ACPI_ADR_SPACE_FIXED_HARDWARE) ||
-		(data->acpi_data.status_register.space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)) {
+	space_id = data->acpi_data.control_register.space_id;
+	if ((space_id != ACPI_ADR_SPACE_FIXED_HARDWARE) ||
+		(space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)) {
 		dprintk("Invalid control/status registers (%x - %x)\n",
 			data->acpi_data.control_register.space_id,
-			data->acpi_data.status_register.space_id);
+			space_id);
 		goto err_out;
 	}
 
This got fixed in 2c701b1 in 2.6.31-rc8, so this is most likely the 
problem that Kurt was encountering.

Kurt, could you try 2.6.31 and see if you still experience the issue?  If 
not, this can be closed.
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