linux/debian/patches-rt/0299-sched-migrate_dis-enab...

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From 7200d432f6acca88cd524ac2ba4d530956270297 Mon Sep 17 00:00:00 2001
Message-Id: <7200d432f6acca88cd524ac2ba4d530956270297.1592846147.git.zanussi@kernel.org>
In-Reply-To: <07cd0dbc80b976663c80755496a03f288decfe5a.1592846146.git.zanussi@kernel.org>
References: <07cd0dbc80b976663c80755496a03f288decfe5a.1592846146.git.zanussi@kernel.org>
2020-02-21 18:07:43 +00:00
From: Scott Wood <swood@redhat.com>
Date: Tue, 24 Sep 2019 14:36:41 +0200
2020-06-23 13:42:59 +00:00
Subject: [PATCH 299/330] =?UTF-8?q?sched:=20migrate=5Fdis/enable:=20Use=20?=
2020-02-21 18:07:43 +00:00
=?UTF-8?q?sleeping=5Flock=E2=80=A6()=20to=20annotate=20sleeping=20points?=
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2020-06-23 13:42:59 +00:00
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.127-rt55.tar.xz
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[ Upstream commit 4230dd3824c3e1785504e6f757ce79a4b55651fa ]
Without this, rcu_note_context_switch() will complain if an RCU read lock
is held when migrate_enable() calls stop_one_cpu(). Likewise when
migrate_disable() calls pin_current_cpu() which calls __read_rt_lock() --
which bypasses the part of the mutex code that calls sleeping_lock_inc().
Signed-off-by: Scott Wood <swood@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
[bigeasy: use sleeping_lock_…() ]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/cpu.c | 2 ++
kernel/sched/core.c | 3 +++
2 files changed, 5 insertions(+)
diff --git a/kernel/cpu.c b/kernel/cpu.c
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index 9f2e05b2e65c..27fe7c8185c9 100644
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--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -307,7 +307,9 @@ void pin_current_cpu(void)
preempt_lazy_enable();
preempt_enable();
+ sleeping_lock_inc();
__read_rt_lock(cpuhp_pin);
+ sleeping_lock_dec();
preempt_disable();
preempt_lazy_disable();
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index a1c0123e7636..3413b9ebef1f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7372,7 +7372,10 @@ void migrate_enable(void)
unpin_current_cpu();
preempt_lazy_enable();
preempt_enable();
+
+ sleeping_lock_inc();
stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
+ sleeping_lock_dec();
tlb_migrate_finish(p->mm);
return;
--
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2.17.1
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