2020-08-28 04:53:35 +00:00
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From a2596b6ffdfe09b8fe9acdf939d4d52a56c0d8f8 Mon Sep 17 00:00:00 2001
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Message-Id: <a2596b6ffdfe09b8fe9acdf939d4d52a56c0d8f8.1596234184.git.zanussi@kernel.org>
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In-Reply-To: <378ee68279f6a7631221f2670a9298620148690d.1596234183.git.zanussi@kernel.org>
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References: <378ee68279f6a7631221f2670a9298620148690d.1596234183.git.zanussi@kernel.org>
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2020-02-21 18:07:43 +00:00
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From: Julien Grall <julien.grall@arm.com>
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Date: Wed, 21 Aug 2019 10:24:09 +0100
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2020-07-15 20:05:29 +00:00
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Subject: [PATCH 295/329] hrtimer: Prevent using hrtimer_grab_expiry_lock() on
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2020-02-21 18:07:43 +00:00
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migration_base
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2020-08-28 04:53:35 +00:00
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.135-rt60.tar.xz
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2020-02-21 18:07:43 +00:00
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[ Upstream commit cef1b87f98823af923a386f3f69149acb212d4a1 ]
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As tglx puts it:
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|If base == migration_base then there is no point to lock soft_expiry_lock
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|simply because the timer is not executing the callback in soft irq context
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|and the whole lock/unlock dance can be avoided.
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Furthermore, all the path leading to hrtimer_grab_expiry_lock() assumes
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timer->base and timer->base->cpu_base are always non-NULL. So it is safe
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to remove the NULL checks here.
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Signed-off-by: Julien Grall <julien.grall@arm.com>
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Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1908211557420.2223@nanos.tec.linutronix.de
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Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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[bigeasy: rewrite changelog]
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/time/hrtimer.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
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index 49d20fe8570f..1a5167c68310 100644
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--- a/kernel/time/hrtimer.c
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+++ b/kernel/time/hrtimer.c
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@@ -943,7 +943,7 @@ void hrtimer_grab_expiry_lock(const struct hrtimer *timer)
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{
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struct hrtimer_clock_base *base = READ_ONCE(timer->base);
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- if (timer->is_soft && base && base->cpu_base) {
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+ if (timer->is_soft && base != &migration_base) {
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spin_lock(&base->cpu_base->softirq_expiry_lock);
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spin_unlock(&base->cpu_base->softirq_expiry_lock);
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}
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--
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2020-06-22 13:14:16 +00:00
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2.17.1
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2020-02-21 18:07:43 +00:00
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