[PATCH v3] cpufreq/pasemi: fix an use-after-free inpas_cpufreq_cpu_init()

The cpu variable is still being used in the of_get_property() call
after the of_node_put() call, which may result in use-after-free.

Fixes: a9acc26b75f ("cpufreq/pasemi: fix possible object reference leak")
Signed-off-by: Wen Yang <wen.yang99 at zte.com.cn>
Cc: "Rafael J. Wysocki" <rjw at rjwysocki.net>
Cc: Viresh Kumar <viresh.kumar at linaro.org>
Cc: Michael Ellerman <mpe at ellerman.id.au>
Cc: linuxppc-dev at lists.ozlabs.org
Cc: linux-pm at vger.kernel.org
Cc: linux-kernel at vger.kernel.org
---
v5: put together the code to get, use, and release cpu device_node.
v4: restore the blank line.
v3: fix a leaked reference.
v2: clean up the code according to the advice of viresh.

 drivers/cpufreq/pasemi-cpufreq.c | 21 +++++++++------------
 1 file changed, 9 insertions(+), 12 deletions(-)

diff --git a/drivers/cpufreq/pasemi-cpufreq.c b/drivers/cpufreq/pasemi-cpufreq.c
index 6b1e4ab..1f0beb7 100644
--- a/drivers/cpufreq/pasemi-cpufreq.c
+++ b/drivers/cpufreq/pasemi-cpufreq.c

@@ -131,10 +131,17 @@ static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
     int err = -ENODEV;

     cpu = of_get_cpu_node(policy->cpu, NULL);
-
-    of_node_put(cpu);
     if (!cpu)
         goto out;

+    max_freqp = of_get_property(cpu, "clock-frequency", NULL);
+    of_node_put(cpu);
+    if (!max_freqp) {
+        err = -EINVAL;
+        goto out;
+    }
+
+    /* we need the freq in kHz */
+    max_freq = *max_freqp / 1000;

     dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
     if (!dn)

@@ -171,16 +178,6 @@ static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
     }

     pr_debug("init cpufreq on CPU %d\n", policy->cpu);
-
-    max_freqp = of_get_property(cpu, "clock-frequency", NULL);
-    if (!max_freqp) {
-        err = -EINVAL;
-        goto out_unmap_sdcpwr;
-    }
-
-    /* we need the freq in kHz */
-    max_freq = *max_freqp / 1000;
-
     pr_debug("max clock-frequency is at %u kHz\n", max_freq);
     pr_debug("initializing frequency table\n");