| Message ID | 1624429583-5720-1-git-send-email-curtis.klein@hpe.com |
|---|---|
| State | New |
| Headers | show |
| Series | watchdog: Fix NULL pointer dereference when releasing cdev | expand |
On Tue, Jun 22, 2021 at 11:26:23PM -0700, Curtis Klein wrote: > watchdog_hrtimer_pretimeout_stop needs the watchdog device to have a > valid pointer to the watchdog core data to stop the pretimeout hrtimer. > Therefore it needs to be called before the pointers are cleared in > watchdog_cdev_unregister. > > Fixes: 7b7d2fdc8c3e ("watchdog: Add hrtimer-based pretimeout feature") > Reported-by: Colin Ian King <colin.king@canonical.com> > Signed-off-by: Curtis Klein <curtis.klein@hpe.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> > --- > drivers/watchdog/watchdog_dev.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c > index 3bab324..ffd8f1a 100644 > --- a/drivers/watchdog/watchdog_dev.c > +++ b/drivers/watchdog/watchdog_dev.c > @@ -1096,6 +1096,8 @@ static void watchdog_cdev_unregister(struct watchdog_device *wdd) > watchdog_stop(wdd); > } > > + watchdog_hrtimer_pretimeout_stop(wdd); > + > mutex_lock(&wd_data->lock); > wd_data->wdd = NULL; > wdd->wd_data = NULL; > @@ -1103,7 +1105,6 @@ static void watchdog_cdev_unregister(struct watchdog_device *wdd) > > hrtimer_cancel(&wd_data->timer); > kthread_cancel_work_sync(&wd_data->work); > - watchdog_hrtimer_pretimeout_stop(wdd); > > put_device(&wd_data->dev); > } > -- > 2.7.4 >
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 3bab324..ffd8f1a 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -1096,6 +1096,8 @@ static void watchdog_cdev_unregister(struct watchdog_device *wdd) watchdog_stop(wdd); } + watchdog_hrtimer_pretimeout_stop(wdd); + mutex_lock(&wd_data->lock); wd_data->wdd = NULL; wdd->wd_data = NULL; @@ -1103,7 +1105,6 @@ static void watchdog_cdev_unregister(struct watchdog_device *wdd) hrtimer_cancel(&wd_data->timer); kthread_cancel_work_sync(&wd_data->work); - watchdog_hrtimer_pretimeout_stop(wdd); put_device(&wd_data->dev); }
watchdog_hrtimer_pretimeout_stop needs the watchdog device to have a valid pointer to the watchdog core data to stop the pretimeout hrtimer. Therefore it needs to be called before the pointers are cleared in watchdog_cdev_unregister. Fixes: 7b7d2fdc8c3e ("watchdog: Add hrtimer-based pretimeout feature") Reported-by: Colin Ian King <colin.king@canonical.com> Signed-off-by: Curtis Klein <curtis.klein@hpe.com> --- drivers/watchdog/watchdog_dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)