From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Mon, 18 Feb 2019 16:57:09 +0100
Subject: [PATCH] x86: lazy-preempt: properly check against preempt-mask
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.25-rt16.tar.xz

should_resched() should check against preempt_offset after unmasking the
need-resched-bit. Otherwise should_resched() won't work for
preempt_offset != 0 and lazy-preempt set.

Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 arch/x86/include/asm/preempt.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/include/asm/preempt.h
+++ b/arch/x86/include/asm/preempt.h
@@ -118,7 +118,7 @@ static __always_inline bool should_resch
 
 	/* preempt count == 0 ? */
 	tmp &= ~PREEMPT_NEED_RESCHED;
-	if (tmp)
+	if (tmp != preempt_offset)
 		return false;
 	if (current_thread_info()->preempt_lazy_count)
 		return false;
