[PATCH RT 07/32] x86: preempt: Check preemption level before looking at lazy-preempt

Steven Rostedt
2020-01-17T17:43:35Z

From: Sebastian Andrzej Siewior <bigeasy@linutronix.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@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.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