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Commit bbe9a70a authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Rafael J. Wysocki
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tick-sched: avoid a maybe-uninitialized warning 

The use of bitfields seems to confuse gcc, leading to a false-positive
warning in all compiler versions:

kernel/time/tick-sched.c: In function 'tick_nohz_idle_exit':
kernel/time/tick-sched.c:538:2: error: 'now' may be used uninitialized in this function [-Werror=maybe-uninitialized]

This introduces a temporary variable to track the flags so gcc
doesn't have to evaluate twice, eliminating the code path that
leads to the warning.

Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85301


Fixes: 1cae544d42d2 ("nohz: Gather tick_sched booleans under a common flag field")
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 792ccb45

kernel/time/tick-sched.c

+6 −3
Original line number Diff line number Diff line
@@ -1134,6 +1134,7 @@ void tick_nohz_idle_restart_tick(void) 
void tick_nohz_idle_exit(void)

{

	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);

	bool idle_active, tick_stopped;

	ktime_t now;



	local_irq_disable();
@@ -1142,14 +1143,16 @@ void tick_nohz_idle_exit(void) 
	WARN_ON_ONCE(ts->timer_expires_base);



	ts->inidle = 0;

	idle_active = ts->idle_active;

	tick_stopped = ts->tick_stopped;



	if (ts->idle_active || ts->tick_stopped)

	if (idle_active || tick_stopped)

		now = ktime_get();



	if (ts->idle_active)

	if (idle_active)

		tick_nohz_stop_idle(ts, now);



	if (ts->tick_stopped)

	if (tick_stopped)

		__tick_nohz_idle_restart_tick(ts, now);



	local_irq_enable();