watchdog_open() does not have wd_data->lock locks at all unlike
the watchdog_release() for instance. Also watchdog_open() calls
watchdog_start() that should be called with wd_data->lock acquired.
The mutex lock should be acquired in the beginning of the function
after getting struct watchdog_core_data wd_data pointer to deal with
different status fields and be able to call watchdog_start(); and
released on exit and on different error paths.
Signed-off-by: Alexey Klimov <aklimov@xxxxxxxxxx>
---
drivers/watchdog/watchdog_dev.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 804236a094f6..d07a864036d9 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -836,7 +836,7 @@ static int watchdog_open(struct inode *inode, struct file *file)
struct watchdog_core_data *wd_data;
struct watchdog_device *wdd;
bool hw_running;
- int err;
+ int err = -EBUSY;
/* Get the corresponding watchdog device */
if (imajor(inode) == MISC_MAJOR)
@@ -845,9 +845,10 @@ static int watchdog_open(struct inode *inode, struct file *file)
wd_data = container_of(inode->i_cdev, struct watchdog_core_data,
cdev);
+ mutex_lock(&wd_data->lock);
/* the watchdog is single open! */
if (test_and_set_bit(_WDOG_DEV_OPEN, &wd_data->status))
- return -EBUSY;
+ goto out_unlock;
wdd = wd_data->wdd;
@@ -856,10 +857,8 @@ static int watchdog_open(struct inode *inode, struct file *file)
* to be unloaded.
*/
hw_running = watchdog_hw_running(wdd);
- if (!hw_running && !try_module_get(wdd->ops->owner)) {
- err = -EBUSY;
+ if (!hw_running && !try_module_get(wdd->ops->owner))
goto out_clear;
- }
err = watchdog_start(wdd);
if (err < 0)
@@ -878,6 +877,7 @@ static int watchdog_open(struct inode *inode, struct file *file)
* applied.
*/
wd_data->open_deadline = KTIME_MAX;
+ mutex_unlock(&wd_data->lock);
/* dev/watchdog is a virtual (and thus non-seekable) filesystem */
return stream_open(inode, file);
@@ -886,6 +886,8 @@ static int watchdog_open(struct inode *inode, struct file *file)
module_put(wd_data->wdd->ops->owner);
out_clear:
clear_bit(_WDOG_DEV_OPEN, &wd_data->status);
+out_unlock:
+ mutex_unlock(&wd_data->lock);
return err;
}
--
2.37.2
