[Xen-devel] [PATCH] x86/cpufreq: check array index before use

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

... rather than after.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- 2010-06-15.orig/xen/arch/x86/acpi/cpufreq/cpufreq.c 2010-07-06 
16:08:59.000000000 +0200
+++ 2010-06-15/xen/arch/x86/acpi/cpufreq/cpufreq.c      2010-07-06 
16:11:48.000000000 +0200
@@ -210,9 +210,11 @@ static u32 get_cur_val(cpumask_t mask)
 
     if (!cpu_isset(cpu, mask))
         cpu = first_cpu(mask);
-    policy = cpufreq_cpu_policy[cpu];
+    if (cpu >= NR_CPUS)
+        return 0;
 
-    if (cpu >= NR_CPUS || !policy || !drv_data[policy->cpu])
+    policy = cpufreq_cpu_policy[cpu];
+    if (!policy || !drv_data[policy->cpu])
         return 0;    
 
     switch (drv_data[policy->cpu]->cpu_feature) {

Attachment: x86-cpufreq-cpu-check.patch
Description: Text document

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