This is a note to let you know that I've just added the patch titled hwmon: (applesmc) check status earlier. to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: hwmon-applesmc-check-status-earlier.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 0e832215939b64039277c0c48cc78a677e865450 Author: Tom Rix <trix@xxxxxxxxxx> Date: Thu Aug 20 06:19:32 2020 -0700 hwmon: (applesmc) check status earlier. [ Upstream commit cecf7560f00a8419396a2ed0f6e5d245ccb4feac ] clang static analysis reports this representative problem applesmc.c:758:10: warning: 1st function call argument is an uninitialized value left = be16_to_cpu(*(__be16 *)(buffer + 6)) >> 2; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ buffer is filled by the earlier call ret = applesmc_read_key(LIGHT_SENSOR_LEFT_KEY, ... This problem is reported because a goto skips the status check. Other similar problems use data from applesmc_read_key before checking the status. So move the checks to before the use. Signed-off-by: Tom Rix <trix@xxxxxxxxxx> Reviewed-by: Henrik Rydberg <rydberg@xxxxxxxxxxx> Link: https://lore.kernel.org/r/20200820131932.10590-1-trix@xxxxxxxxxx Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/hwmon/applesmc.c b/drivers/hwmon/applesmc.c index 5c677ba440143..b201129a9beae 100644 --- a/drivers/hwmon/applesmc.c +++ b/drivers/hwmon/applesmc.c @@ -760,15 +760,18 @@ static ssize_t applesmc_light_show(struct device *dev, } ret = applesmc_read_key(LIGHT_SENSOR_LEFT_KEY, buffer, data_length); + if (ret) + goto out; /* newer macbooks report a single 10-bit bigendian value */ if (data_length == 10) { left = be16_to_cpu(*(__be16 *)(buffer + 6)) >> 2; goto out; } left = buffer[2]; + + ret = applesmc_read_key(LIGHT_SENSOR_RIGHT_KEY, buffer, data_length); if (ret) goto out; - ret = applesmc_read_key(LIGHT_SENSOR_RIGHT_KEY, buffer, data_length); right = buffer[2]; out: @@ -817,12 +820,11 @@ static ssize_t applesmc_show_fan_speed(struct device *dev, to_index(attr)); ret = applesmc_read_key(newkey, buffer, 2); - speed = ((buffer[0] << 8 | buffer[1]) >> 2); - if (ret) return ret; - else - return snprintf(sysfsbuf, PAGE_SIZE, "%u\n", speed); + + speed = ((buffer[0] << 8 | buffer[1]) >> 2); + return snprintf(sysfsbuf, PAGE_SIZE, "%u\n", speed); } static ssize_t applesmc_store_fan_speed(struct device *dev, @@ -858,12 +860,11 @@ static ssize_t applesmc_show_fan_manual(struct device *dev, u8 buffer[2]; ret = applesmc_read_key(FANS_MANUAL, buffer, 2); - manual = ((buffer[0] << 8 | buffer[1]) >> to_index(attr)) & 0x01; - if (ret) return ret; - else - return snprintf(sysfsbuf, PAGE_SIZE, "%d\n", manual); + + manual = ((buffer[0] << 8 | buffer[1]) >> to_index(attr)) & 0x01; + return snprintf(sysfsbuf, PAGE_SIZE, "%d\n", manual); } static ssize_t applesmc_store_fan_manual(struct device *dev, @@ -879,10 +880,11 @@ static ssize_t applesmc_store_fan_manual(struct device *dev, return -EINVAL; ret = applesmc_read_key(FANS_MANUAL, buffer, 2); - val = (buffer[0] << 8 | buffer[1]); if (ret) goto out; + val = (buffer[0] << 8 | buffer[1]); + if (input) val = val | (0x01 << to_index(attr)); else @@ -958,13 +960,12 @@ static ssize_t applesmc_key_count_show(struct device *dev, u32 count; ret = applesmc_read_key(KEY_COUNT_KEY, buffer, 4); - count = ((u32)buffer[0]<<24) + ((u32)buffer[1]<<16) + - ((u32)buffer[2]<<8) + buffer[3]; - if (ret) return ret; - else - return snprintf(sysfsbuf, PAGE_SIZE, "%d\n", count); + + count = ((u32)buffer[0]<<24) + ((u32)buffer[1]<<16) + + ((u32)buffer[2]<<8) + buffer[3]; + return snprintf(sysfsbuf, PAGE_SIZE, "%d\n", count); } static ssize_t applesmc_key_at_index_read_show(struct device *dev,