[RT,02/25] x86: preempt: Check preemption level before looking at lazy-preempt
diff mbox series

Message ID cdc2d810557adb7ec3ab4e24cce3ffd8c128f16b.1582320278.git.zanussi@kernel.org
State New
Headers show
Series
  • Linux v4.14.170-rt75-rc1
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Commit Message

Tom Zanussi Feb. 21, 2020, 9:24 p.m. UTC
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

v4.14.170-rt75-rc1 stable review patch.
If anyone has any objections, please let me know.

-----------


[ 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: Tom Zanussi <zanussi@kernel.org>
---
 arch/x86/include/asm/preempt.h | 2 ++
 1 file changed, 2 insertions(+)

Patch
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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);