From a913f50706b21c7933f53cec678bb9a1c2383499 Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@osdl.org>
Date: Sat, 10 Jun 2006 09:54:13 -0700
Subject: [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>
---
 drivers/acpi/processor_perflib.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

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);
-- 
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