linux-kernel - [tip: timers/core] timers: Initialize base::next_expiry_recalc in timers_prepare

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Date:   Sat, 09 Apr 2022 20:22:32 -0000
From:   "tip-bot2 for Anna-Maria Behnsen" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "Anna-Maria Behnsen" <anna-maria@...utronix.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Frederic Weisbecker <frederic@...nel.org>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [tip: timers/core] timers: Initialize base::next_expiry_recalc in
 timers_prepare_cpu()

The following commit has been merged into the timers/core branch of tip:

Commit-ID:     2731aa7d65dbb31c6dad14347c37d522bb3bc7c6
Gitweb:        https://git.kernel.org/tip/2731aa7d65dbb31c6dad14347c37d522bb3bc7c6
Author:        Anna-Maria Behnsen <anna-maria@...utronix.de>
AuthorDate:    Tue, 05 Apr 2022 21:17:31 +02:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Sat, 09 Apr 2022 22:19:39 +02:00

timers: Initialize base::next_expiry_recalc in timers_prepare_cpu()

When base::next_expiry_recalc is not initialized to false during cpu
bringup in HOTPLUG_CPU and is accidently true and no timer is queued in the
meantime, the loop through the wheel to find __next_timer_interrupt() might
be done for nothing.

Therefore initialize base::next_expiry_recalc to false in
timers_prepare_cpu().

Signed-off-by: Anna-Maria Behnsen <anna-maria@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Frederic Weisbecker <frederic@...nel.org>
Link: https://lore.kernel.org/r/20220405191732.7438-2-anna-maria@linutronix.de

---
 kernel/time/timer.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index 9dd2a39..204d6cd 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1953,6 +1953,7 @@ int timers_prepare_cpu(unsigned int cpu)
 		base = per_cpu_ptr(&timer_bases[b], cpu);
 		base->clk = jiffies;
 		base->next_expiry = base->clk + NEXT_TIMER_MAX_DELTA;
+		base->next_expiry_recalc = false;
 		base->timers_pending = false;
 		base->is_idle = false;
 	}