Add sanity check which ensures that there are no two restart handlers
registered with the same priority. Normally it's a direct sign of a
problem if two handlers use the same priority.
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
kernel/reboot.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 6bcc5d6a6572..e6659ae329f1 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -182,7 +182,20 @@ static ATOMIC_NOTIFIER_HEAD(restart_handler_list);
*/
int register_restart_handler(struct notifier_block *nb)
{
- return atomic_notifier_chain_register(&restart_handler_list, nb);
+ int ret;
+
+ ret = atomic_notifier_chain_register(&restart_handler_list, nb);
+ if (ret)
+ return ret;
+
+ /*
+ * Handler must have unique priority. Otherwise call order is
+ * determined by registration order, which is unreliable.
+ */
+ WARN(!atomic_notifier_has_unique_priority(&restart_handler_list, nb),
+ "restart handler must have unique priority\n");
+
+ return 0;
}
EXPORT_SYMBOL(register_restart_handler);
--
2.33.1
