Update cpufreq statistic protection

For struct pm_px, there are 3 pointer: pxpt, pt, trans_pt.
Partly free pointer 'pt' and 'trans_pt' will result in little memory
leak, and what is more, will result in protection issue when user
access px statistic info through libxc.

Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>

diff --git a/xen/drivers/cpufreq/utility.c b/xen/drivers/cpufreq/utility.c
index b9330c1de2c9539fbc47e8185365bb28cf7b3aaf..1c8176fabe4ed81ff8d95da882ffbe8e80b98847 100644 (file)
--- a/xen/drivers/cpufreq/utility.c
+++ b/xen/drivers/cpufreq/utility.c
@@ -73,27 +73,30 @@ int cpufreq_statistic_init(unsigned int cpuid)
     struct pm_px *pxpt = cpufreq_statistic_data[cpuid];
     const struct processor_pminfo *pmpt = processor_pminfo[cpuid];
 
-    count = pmpt->perf.state_count;
-
     if ( !pmpt )
         return -EINVAL;
 
+    if ( pxpt )
+        return 0;
+
+    count = pmpt->perf.state_count;
+
+    pxpt = xmalloc(struct pm_px);
     if ( !pxpt )
-    {
-        pxpt = xmalloc(struct pm_px);
-        if ( !pxpt )
-            return -ENOMEM;
-        memset(pxpt, 0, sizeof(*pxpt));
-        cpufreq_statistic_data[cpuid] = pxpt;
-    }
+        return -ENOMEM;
+    memset(pxpt, 0, sizeof(*pxpt));
+    cpufreq_statistic_data[cpuid] = pxpt;
 
     pxpt->u.trans_pt = xmalloc_array(uint64_t, count * count);
-    if (!pxpt->u.trans_pt)
+    if (!pxpt->u.trans_pt) {
+        xfree(pxpt);
         return -ENOMEM;
+    }
 
     pxpt->u.pt = xmalloc_array(struct pm_px_val, count);
     if (!pxpt->u.pt) {
         xfree(pxpt->u.trans_pt);
+        xfree(pxpt);
         return -ENOMEM;
     }
 
@@ -120,7 +123,8 @@ void cpufreq_statistic_exit(unsigned int cpuid)
         return;
     xfree(pxpt->u.trans_pt);
     xfree(pxpt->u.pt);
-    memset(pxpt, 0, sizeof(struct pm_px));
+    xfree(pxpt);
+    cpufreq_statistic_data[cpuid] = NULL;
 }
 
 void cpufreq_statistic_reset(unsigned int cpuid)