From bbe9a70a478129f3f9b2003415d0c36afcea210f Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 9 Apr 2018 14:23:33 +0200 Subject: [PATCH] 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: Arnd Bergmann Signed-off-by: Rafael J. Wysocki --- kernel/time/tick-sched.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 956831cf6cfb..e35a6fced00c 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -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(); -- 2.39.5