Message ID | 20220924001751.1726369-1-floridsleeves@gmail.com (mailing list archive) |
---|---|
State | Accepted |
Headers | show |
Series | [v3] drivers/hwmon/adm9240: fix data race in adm9240_fan_read | expand |
On Fri, Sep 23, 2022 at 05:17:51PM -0700, Li Zhong wrote: > 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 <floridsleeves@gmail.com> Applied. Thanks, Guenter
diff --git a/drivers/hwmon/adm9240.c b/drivers/hwmon/adm9240.c index 483cd757abd3..40e3558d3709 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]);
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 <floridsleeves@gmail.com> --- drivers/hwmon/adm9240.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)