Merge tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fix from Guenter Roeck:
 "Fix potential crash condition in applesmc driver"

* tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: (applesmc) Check key count before proceeding

1 files changed, 10 insertions, 1 deletions

diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
index 62c2e32e25ef..98814d12a604 100644
--- a/drivers/hwmon/applesmc.c
+++ b/drivers/hwmon/applesmc.c
@@ -525,16 +525,25 @@ static int applesmc_init_smcreg_try(void)
 {
         struct applesmc_registers *s = &smcreg;
         bool left_light_sensor, right_light_sensor;
+        unsigned int count;
         u8 tmp[1];
         int ret;
 
         if (s->init_complete)
                 return 0;
 
-        ret = read_register_count(&s->key_count);
+        ret = read_register_count(&count);
         if (ret)
                 return ret;
 
+        if (s->cache && s->key_count != count) {
+                pr_warn("key count changed from %d to %d\n",
+                        s->key_count, count);
+                kfree(s->cache);
+                s->cache = NULL;
+        }
+        s->key_count = count;
+
         if (!s->cache)
                 s->cache = kcalloc(s->key_count, sizeof(*s->cache), GFP_KERNEL);
         if (!s->cache)