[Xen-devel] [PATCH]Make sure processor_pminfo initialized before use it

["Zhang, Yang Z" <yang.z.zhang@xxxxxxxxx>]

Make sure processor_pminfo not null before use it

If processor_pminfo not initialized, it will cause xen panic.

Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx>

diff -r bdd19847ae63 xen/drivers/cpufreq/cpufreq.c
--- a/xen/drivers/cpufreq/cpufreq.c     Wed Sep 07 10:37:48 2011 +0100
+++ b/xen/drivers/cpufreq/cpufreq.c     Thu Sep 08 13:40:23 2011 +0800
@@ -91,7 +91,7 @@ int __init cpufreq_register_governor(str

 int cpufreq_limit_change(unsigned int cpu)
 {
-    struct processor_performance *perf = &processor_pminfo[cpu]->perf;
+    struct processor_performance *perf;
     struct cpufreq_policy *data;
     struct cpufreq_policy policy;

@@ -99,6 +99,7 @@ int cpufreq_limit_change(unsigned int cp
         !processor_pminfo[cpu])
         return -ENODEV;

+    perf = &processor_pminfo[cpu]->perf;
     if (perf->platform_limit >= perf->state_count)
         return -EINVAL;

@@ -120,12 +121,14 @@ int cpufreq_add_cpu(unsigned int cpu)
     struct cpufreq_dom *cpufreq_dom = NULL;
     struct cpufreq_policy new_policy;
     struct cpufreq_policy *policy;
-    struct processor_performance *perf = &processor_pminfo[cpu]->perf;
+    struct processor_performance *perf;

     /* to protect the case when Px was not controlled by xen */
-    if (!processor_pminfo[cpu]      ||
-        !(perf->init & XEN_PX_INIT) ||
-        !cpu_online(cpu))
+    if (!processor_pminfo[cpu] || !cpu_online(cpu))
+        return -EINVAL;
+
+    perf = &processor_pminfo[cpu]->perf;
+    if (!(perf->init & XEN_PX_INIT))
         return -EINVAL;

     if (!cpufreq_driver)
@@ -261,12 +264,14 @@ int cpufreq_del_cpu(unsigned int cpu)
     struct list_head *pos;
     struct cpufreq_dom *cpufreq_dom = NULL;
     struct cpufreq_policy *policy;
-    struct processor_performance *perf = &processor_pminfo[cpu]->perf;
+    struct processor_performance *perf;

     /* to protect the case when Px was not controlled by xen */
-    if (!processor_pminfo[cpu]      ||
-        !(perf->init & XEN_PX_INIT) ||
-        !cpu_online(cpu))
+    if (!processor_pminfo[cpu] || !cpu_online(cpu))
+        return -EINVAL;
+
+    perf = &processor_pminfo[cpu]->perf;
+    if (!(perf->init & XEN_PX_INIT))
         return -EINVAL;

     if (!per_cpu(cpufreq_cpu_policy, cpu))



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