From 5f4513864304672e6ea9eac60583eeac32e679f2 Mon Sep 17 00:00:00 2001 From: Henrik Rydberg Date: Thu, 26 Sep 2013 08:33:16 +0200 Subject: [PATCH] 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: Suggested-by: Guenter Roeck Signed-off-by: Henrik Rydberg Cc: stable@vger.kernel.org Signed-off-by: Guenter Roeck --- drivers/hwmon/applesmc.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) 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)