[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>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/acpi/processor_perflib.c b/drivers/acpi/processor_perflib.c
index abbdb37a7f5f..f36db22ce1ae 100644
--- 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);