From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E18F5C2BA83 for ; Wed, 12 Feb 2020 09:44:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B517A20848 for ; Wed, 12 Feb 2020 09:44:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="I4vXAUw9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729052AbgBLJoC (ORCPT ); Wed, 12 Feb 2020 04:44:02 -0500 Received: from merlin.infradead.org ([205.233.59.134]:59452 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728891AbgBLJoA (ORCPT ); Wed, 12 Feb 2020 04:44:00 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-Id:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=HdUKWfX4HpXaIQLUXWQWHKnnpih/LrElkhlwPym/L2Y=; b=I4vXAUw9vSIXbRHqgQKHw9eTXc XzrzSGQDMctfNR5wx3O9uNvwkU5ZwLdexavrW1/kTtltD4Ii5YBY5MsYmSQ6jOYl1BkoPyzv/EZPL wctX8vPLP0HSqQuI4zsWNeXAJlFridKsYQg4J/21keqA4nZETGWX5ghQtGDB+0C3UVb1vNevRg7WU 1oVmuO8wrV+Uz9wdMdbsguJGtmOfA4pChszsjt6XDogf3hevcyH4ZnjCq+NorZh8aaW9qfKNcUyTN +mquc54tKyma/1KzRhPQbaGLR6b4zXHl14HPVvZJ8fmPTSTepYFfmE4RhMsYqqdmCCIAxJDilTkrI fcN4otlw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1j1oYG-0006Ar-Q2; Wed, 12 Feb 2020 09:43:24 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 0F3773077F2; Wed, 12 Feb 2020 10:41:33 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 59DA72B9154EB; Wed, 12 Feb 2020 10:43:21 +0100 (CET) Message-Id: <20200212094107.894657838@infradead.org> User-Agent: quilt/0.65 Date: Wed, 12 Feb 2020 10:32:15 +0100 From: Peter Zijlstra To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, rostedt@goodmis.org Cc: peterz@infradead.org, mingo@kernel.org, joel@joelfernandes.org, gregkh@linuxfoundation.org, gustavo@embeddedor.com, tglx@linutronix.de, paulmck@kernel.org, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com Subject: [PATCH 5/8] x86,tracing: Mark debug_stack_{set_zero,reset)() notrace References: <20200212093210.468391728@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Because do_nmi() must not call into tracing outside of nmi_enter()/nmi_exit(), these functions must be notrace. Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/kernel/cpu/common.c | 4 ++-- arch/x86/kernel/nmi.c | 6 ++++++ 2 files changed, 8 insertions(+), 2 deletions(-) --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1690,14 +1690,14 @@ void syscall_init(void) DEFINE_PER_CPU(int, debug_stack_usage); DEFINE_PER_CPU(u32, debug_idt_ctr); -void debug_stack_set_zero(void) +void notrace debug_stack_set_zero(void) { this_cpu_inc(debug_idt_ctr); load_current_idt(); } NOKPROBE_SYMBOL(debug_stack_set_zero); -void debug_stack_reset(void) +void notrace debug_stack_reset(void) { if (WARN_ON(!this_cpu_read(debug_idt_ctr))) return; --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -534,6 +534,9 @@ do_nmi(struct pt_regs *regs, long error_ } #endif + /* + * It is important that no tracing happens before nmi_enter()! + */ nmi_enter(); inc_irq_stat(__nmi_count); @@ -542,6 +545,9 @@ do_nmi(struct pt_regs *regs, long error_ default_do_nmi(regs); nmi_exit(); + /* + * No tracing after nmi_exit()! + */ #ifdef CONFIG_X86_64 if (unlikely(this_cpu_read(update_debug_stack))) {