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Message-Id: <20200123203943.326004971@goodmis.org>
Date: Thu, 23 Jan 2020 15:39:37 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: linux-kernel@...r.kernel.org,
linux-rt-users <linux-rt-users@...r.kernel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>,
Carsten Emde <C.Emde@...dl.org>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
John Kacur <jkacur@...hat.com>,
Julia Cartwright <julia@...com>,
Daniel Wagner <wagi@...om.org>,
Tom Zanussi <zanussi@...nel.org>
Subject: [PATCH RT 07/30] x86: preempt: Check preemption level before looking at lazy-preempt
4.19.94-rt39-rc2 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
[ Upstream commit 19fc8557f2323c52b26561651ed4d51fc688a740 ]
Before evaluating the lazy-preempt state it must be ensure that the
preempt-count is zero.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
---
arch/x86/include/asm/preempt.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h
index f66708779274..afa0e42ccdd1 100644
--- a/arch/x86/include/asm/preempt.h
+++ b/arch/x86/include/asm/preempt.h
@@ -96,6 +96,8 @@ static __always_inline bool __preempt_count_dec_and_test(void)
if (____preempt_count_dec_and_test())
return true;
#ifdef CONFIG_PREEMPT_LAZY
+ if (preempt_count())
+ return false;
if (current_thread_info()->preempt_lazy_count)
return false;
return test_thread_flag(TIF_NEED_RESCHED_LAZY);
--
2.24.1
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