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authorCurtis Klein <curtis.klein@hpe.com>2021-06-22 23:26:23 -0700
committerWim Van Sebroeck <wim@linux-watchdog.org>2021-08-22 10:28:07 +0200
commitc7b178dae139f8857edc50888cfbf251cd974a38 (patch)
tree8cf6ad286f48f6c3909c68100a609833bc8a500b
parentcf6ea9542372a966544d947c17c94048d4883325 (diff)
downloadlinux-c7b178dae139f8857edc50888cfbf251cd974a38.tar.bz2
watchdog: Fix NULL pointer dereference when releasing cdev
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> Link: https://lore.kernel.org/r/1624429583-5720-1-git-send-email-curtis.klein@hpe.com Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
-rw-r--r--drivers/watchdog/watchdog_dev.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 5bf795c1b346..f408967ff1a4 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);
}