4.9-stable review patch. If anyone has any objections, please let me know.
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From: Anna-Maria Gleixner anna-maria@linutronix.de
commit 80d20d35af1edd632a5e7a3b9c0ab7ceff92769e upstream.
local_timer_softirq_pending() checks whether the timer softirq is pending with: local_softirq_pending() & TIMER_SOFTIRQ.
This is wrong because TIMER_SOFTIRQ is the softirq number and not a bitmask. So the test checks for the wrong bit.
Use BIT(TIMER_SOFTIRQ) instead.
Fixes: 5d62c183f9e9 ("nohz: Prevent a timer interrupt storm in tick_nohz_stop_sched_tick()") Signed-off-by: Anna-Maria Gleixner anna-maria@linutronix.de Signed-off-by: Thomas Gleixner tglx@linutronix.de Reviewed-by: Paul E. McKenney paulmck@linux.vnet.ibm.com Reviewed-by: Daniel Bristot de Oliveira bristot@redhat.com Acked-by: Frederic Weisbecker frederic@kernel.org Cc: bigeasy@linutronix.de Cc: peterz@infradead.org Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20180731161358.29472-1-anna-maria@linutronix.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/time/tick-sched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -665,7 +665,7 @@ static void tick_nohz_restart(struct tic
static inline bool local_timer_softirq_pending(void) { - return local_softirq_pending() & TIMER_SOFTIRQ; + return local_softirq_pending() & BIT(TIMER_SOFTIRQ); }
static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts,