From: Sebastian Andrzej Siewior Date: Wed, 14 Aug 2019 17:08:58 +0200 Subject: [PATCH 291/353] x86: preempt: Check preemption level before looking at lazy-preempt Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=ebc55480887bfaef01412510792f2ce1a77b3654 [ 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 Signed-off-by: Steven Rostedt (VMware) --- 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);