From: Li Zhong Date: Sat, 24 Sep 2022 00:17:51 +0000 (-0700) Subject: hwmon: (adm9240) fix data race in adm9240_fan_read X-Git-Tag: v6.6.17~6502^2~26 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=8887516f01066375d70162a978b3fd9d73695878;p=platform%2Fkernel%2Flinux-rpi.git hwmon: (adm9240) fix data race in adm9240_fan_read In adm9240_read() adm9240_fan_read() adm9240_write_fan_div(), it assumes that the caller of adm9240_write_fan_div() must hold data->update_lock. Otherwise, it may cause data races when data is updated by other threads. Signed-off-by: Li Zhong Link: https://lore.kernel.org/r/20220924001751.1726369-1-floridsleeves@gmail.com Signed-off-by: Guenter Roeck --- diff --git a/drivers/hwmon/adm9240.c b/drivers/hwmon/adm9240.c index 483cd75..40e3558 100644 --- a/drivers/hwmon/adm9240.c +++ b/drivers/hwmon/adm9240.c @@ -501,17 +501,23 @@ static int adm9240_fan_read(struct device *dev, u32 attr, int channel, long *val switch (attr) { case hwmon_fan_input: + mutex_lock(&data->update_lock); err = regmap_read(data->regmap, ADM9240_REG_FAN(channel), ®val); - if (err < 0) + if (err < 0) { + mutex_unlock(&data->update_lock); return err; + } if (regval == 255 && data->fan_div[channel] < 3) { /* adjust fan clock divider on overflow */ err = adm9240_write_fan_div(data, channel, ++data->fan_div[channel]); - if (err) + if (err) { + mutex_unlock(&data->update_lock); return err; + } } *val = FAN_FROM_REG(regval, BIT(data->fan_div[channel])); + mutex_unlock(&data->update_lock); break; case hwmon_fan_div: *val = BIT(data->fan_div[channel]);