[PATCH] powernow-k8 crash workaround

From: Andrew Morton <akpm@osdl.org>

Work around the oops reported in
http://bugzilla.kernel.org/show_bug.cgi?id=6478.

Thanks to Ralf Hildebrandt <ralf.hildebrandt@charite.de> for testing and
reporting.

Acked-by: Dave Jones <davej@codemonkey.org.uk>
Cc: "Brown, Len" <len.brown@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index abbdb37..f36db22 100644 (file)
--- a/drivers/acpi/processor_perflib.c
+++ b/drivers/acpi/processor_perflib.c
@@ -577,6 +577,8 @@ acpi_processor_register_performance(struct acpi_processor_performance
                return_VALUE(-EBUSY);
        }
 
+       WARN_ON(!performance);
+
        pr->performance = performance;
 
        if (acpi_processor_get_performance_info(pr)) {
@@ -609,7 +611,8 @@ acpi_processor_unregister_performance(struct acpi_processor_performance
                return_VOID;
        }
 
-       kfree(pr->performance->states);
+       if (pr->performance)
+               kfree(pr->performance->states);
        pr->performance = NULL;
 
        acpi_cpufreq_remove_file(pr);