[PATCH 4.16 50/52] clocksource: Initialize cs->wd_list

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

commit 5b9e886a4af97574ca3ce1147f35545da0e7afc7 upstream.

A number of places relies on list_empty(&cs->wd_list), however the
list_head does not get initialized. Do so upon registration, such that
thereafter it is possible to rely on list_empty() correctly reflecting
the list membership status.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Tested-by: Diego Viola <diego.viola@xxxxxxxxx>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Cc: len.brown@xxxxxxxxx
Cc: rjw@xxxxxxxxxxxxx
Cc: rui.zhang@xxxxxxxxx
Link: https://lkml.kernel.org/r/20180430100344.472662715@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 kernel/time/clocksource.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -332,6 +332,8 @@ static void clocksource_resume_watchdog(
 
 static void clocksource_enqueue_watchdog(struct clocksource *cs)
 {
+	INIT_LIST_HEAD(&cs->wd_list);
+
 	if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) {
 		/* cs is a clocksource to be watched. */
 		list_add(&cs->wd_list, &watchdog_list);