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From: tip-bot for Anna-Maria Gleixner <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: tglx@linutronix.de, linux-kernel@vger.kernel.org,
	anna-maria@linutronix.de, hpa@zytor.com,
	paulmck@linux.vnet.ibm.com, frederic@kernel.org,
	mingo@kernel.org, bristot@redhat.com
Subject: [tip:timers/urgent] nohz: Fix local_timer_softirq_pending()
Date: Tue, 31 Jul 2018 13:13:28 -0700
Message-ID: <tip-80d20d35af1edd632a5e7a3b9c0ab7ceff92769e@git.kernel.org> (raw)
In-Reply-To: <20180731161358.29472-1-anna-maria@linutronix.de>

Commit-ID:  80d20d35af1edd632a5e7a3b9c0ab7ceff92769e
Gitweb:     https://git.kernel.org/tip/80d20d35af1edd632a5e7a3b9c0ab7ceff92769e
Author:     Anna-Maria Gleixner <anna-maria@linutronix.de>
AuthorDate: Tue, 31 Jul 2018 18:13:58 +0200
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 31 Jul 2018 22:08:44 +0200

nohz: Fix local_timer_softirq_pending()

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

---
 kernel/time/tick-sched.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index da9455a6b42b..5b33e2f5c0ed 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -642,7 +642,7 @@ static void tick_nohz_restart(struct tick_sched *ts, ktime_t now)
 
 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_next_event(struct tick_sched *ts, int cpu)

      parent reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-31 16:13 [PATCH] " Anna-Maria Gleixner
2018-07-31 16:50 ` Paul E. McKenney
2018-07-31 17:07 ` Daniel Bristot de Oliveira
2018-07-31 17:14 ` Frederic Weisbecker
2018-07-31 20:13 ` tip-bot for Anna-Maria Gleixner [this message]

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