Messages in this thread | | | Subject | Re: [PATCH] watchdog: Fix an invalid memory access in 'watchdog_cdev_unregister()' | From | Guenter Roeck <> | Date | Thu, 29 Jul 2021 09:27:31 -0700 |
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On 7/29/21 9:16 AM, Christophe JAILLET wrote: > A few lines before 'watchdog_hrtimer_pretimeout_stop(wdd)', we explicitly > set 'wdd->wd_data' to NULL. > So, it is more than likely than this call will lead to an invalid > memory access. > > Move this call before the 'wdd->wd_data = NULL;' > > Fixes: 7b7d2fdc8c3e ("watchdog: Add hrtimer-based pretimeout feature") > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> > --- > Completely untested! > Not sure at all, that it is the way to fix it.
Nice catch. Should be ok.
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 3bab32485273..ffd8f1a82355 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); > } >
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