hwmon: (applesmc) Check key count before proceeding
After reports from Chris and Josh Boyer of a rare crash in applesmc,
Guenter pointed at the initialization problem fixed below. The patch
has not been verified to fix the crash, but should be applied
regardless.
Reported-by: <[email protected]>
Suggested-by: Guenter Roeck <[email protected]>
Signed-off-by: Henrik Rydberg <[email protected]>
Cc: [email protected]
Signed-off-by: Guenter Roeck <[email protected]>
diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c
index 62c2e32..98814d1 100644
--- a/drivers/hwmon/applesmc.c
+++ b/drivers/hwmon/applesmc.c
@@ -525,16 +525,25 @@
{
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)
