On 05/07/2018 08:18 PM, Jia-Ju Bai wrote:
The write operation to "wdt->timeout" is protected by
the lock on line 118, but the read operation to
this data on line 105 is not protected by the lock.
Thus, there may exist a data race for "wdt->timeout".
To fix this data race, the read operation to "wdt->timeout"
should be also protected by the lock.
There is no race. There is already a mutex in the watchdog core which serializes
calls to the various API functions. It would make more sense to drop drv->lock
from the driver.
Guenter
Signed-off-by: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
---
drivers/watchdog/mena21_wdt.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/watchdog/mena21_wdt.c b/drivers/watchdog/mena21_wdt.c
index 25d5d2b8cfbe..05ca69042829 100644
--- a/drivers/watchdog/mena21_wdt.c
+++ b/drivers/watchdog/mena21_wdt.c
@@ -102,14 +102,15 @@ static int a21_wdt_set_timeout(struct watchdog_device *wdt,
return -EINVAL;
}
+ mutex_lock(&drv->lock);
+
if (timeout == 30 && wdt->timeout == 1) {
+ mutex_unlock(&drv->lock);
dev_err(wdt->parent,
"Transition from fast to slow mode not allowed\n");
return -EINVAL;
}
- mutex_lock(&drv->lock);
-
if (timeout == 1)
gpio_set_value(drv->gpios[GPIO_WD_FAST], 1);
else
--
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