From 148cdab3ace63f2ec560f4aa496a0910e85cac12 Mon Sep 17 00:00:00 2001 Message-Id: <148cdab3ace63f2ec560f4aa496a0910e85cac12.1601675152.git.zanussi@kernel.org> In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org> References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org> From: Sebastian Andrzej Siewior Date: Mon, 18 Feb 2019 16:57:09 +0100 Subject: [PATCH 240/333] x86: lazy-preempt: properly check against preempt-mask Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.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 --- arch/x86/include/asm/preempt.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h index 22992c837795..f66708779274 100644 --- a/arch/x86/include/asm/preempt.h +++ b/arch/x86/include/asm/preempt.h @@ -118,7 +118,7 @@ static __always_inline bool should_resched(int preempt_offset) /* preempt count == 0 ? */ tmp &= ~PREEMPT_NEED_RESCHED; - if (tmp) + if (tmp != preempt_offset) return false; if (current_thread_info()->preempt_lazy_count) return false; -- 2.17.1