clocksource: Initialize cs->wd_list

BugLink: http://bugs.launchpad.net/bugs/1778759
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@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Diego Viola <diego.viola@gmail.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: stable@vger.kernel.org
Cc: len.brown@intel.com
Cc: rjw@rjwysocki.net
Cc: rui.zhang@intel.com
Link: https://lkml.kernel.org/r/20180430100344.472662715@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index ab7f7c6d4f07c25c07a22151347fd6592ae43a6e..b06361b1585497d26f8bc8b25592565270550042 100644 (file)
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -332,6 +332,8 @@ static void clocksource_resume_watchdog(void)
 
 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);