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=-2.7 required=3.0 tests=DATE_IN_PAST_03_06, 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 610D6C4332B for ; Fri, 20 Mar 2020 22:05:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C65820777 for ; Fri, 20 Mar 2020 22:05:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727693AbgCTWFO (ORCPT ); Fri, 20 Mar 2020 18:05:14 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:37505 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727425AbgCTWES (ORCPT ); Fri, 20 Mar 2020 18:04:18 -0400 Received: from p5de0bf0b.dip0.t-ipconnect.de ([93.224.191.11] helo=nanos.tec.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jFPk2-0004TY-Bh; Fri, 20 Mar 2020 23:03:46 +0100 Received: from nanos.tec.linutronix.de (localhost [IPv6:::1]) by nanos.tec.linutronix.de (Postfix) with ESMTP id DB9A41039FC; Fri, 20 Mar 2020 23:03:45 +0100 (CET) Message-Id: <20200320180032.895128936@linutronix.de> User-Agent: quilt/0.65 Date: Fri, 20 Mar 2020 19:00:01 +0100 From: Thomas Gleixner To: LKML Cc: x86@kernel.org, Paul McKenney , Josh Poimboeuf , "Joel Fernandes (Google)" , "Steven Rostedt (VMware)" , Masami Hiramatsu , Alexei Starovoitov , Frederic Weisbecker , Mathieu Desnoyers , Brian Gerst , Juergen Gross , Alexandre Chartre , Peter Zijlstra , Tom Lendacky , Paolo Bonzini , kvm@vger.kernel.org Subject: [RESEND][patch V3 05/23] tracing: Provide lockdep less trace_hardirqs_on/off() variants References: <20200320175956.033706968@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-transfer-encoding: 8-bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org trace_hardirqs_on/off() is only partially safe vs. RCU idle. The tracer core itself is safe, but the resulting tracepoints can be utilized by e.g. BPF which is unsafe. Provide variants which do not contain the lockdep invocation so the lockdep and tracer invocations can be split at the call site and placed properly. The new variants also do not use rcuidle as they are going to be called from entry code after/before context tracking. Signed-off-by: Thomas Gleixner --- V2: New patch --- include/linux/irqflags.h | 4 ++++ kernel/trace/trace_preemptirq.c | 23 +++++++++++++++++++++++ 2 files changed, 27 insertions(+) --- a/include/linux/irqflags.h +++ b/include/linux/irqflags.h @@ -29,6 +29,8 @@ #endif #ifdef CONFIG_TRACE_IRQFLAGS + extern void __trace_hardirqs_on(void); + extern void __trace_hardirqs_off(void); extern void trace_hardirqs_on(void); extern void trace_hardirqs_off(void); # define trace_hardirq_context(p) ((p)->hardirq_context) @@ -52,6 +54,8 @@ do { \ current->softirq_context--; \ } while (0) #else +# define __trace_hardirqs_on() do { } while (0) +# define __trace_hardirqs_off() do { } while (0) # define trace_hardirqs_on() do { } while (0) # define trace_hardirqs_off() do { } while (0) # define trace_hardirq_context(p) 0 --- a/kernel/trace/trace_preemptirq.c +++ b/kernel/trace/trace_preemptirq.c @@ -19,6 +19,17 @@ /* Per-cpu variable to prevent redundant calls when IRQs already off */ static DEFINE_PER_CPU(int, tracing_irq_cpu); +void __trace_hardirqs_on(void) +{ + if (this_cpu_read(tracing_irq_cpu)) { + if (!in_nmi()) + trace_irq_enable(CALLER_ADDR0, CALLER_ADDR1); + tracer_hardirqs_on(CALLER_ADDR0, CALLER_ADDR1); + this_cpu_write(tracing_irq_cpu, 0); + } +} +NOKPROBE_SYMBOL(__trace_hardirqs_on); + void trace_hardirqs_on(void) { if (this_cpu_read(tracing_irq_cpu)) { @@ -33,6 +44,18 @@ void trace_hardirqs_on(void) EXPORT_SYMBOL(trace_hardirqs_on); NOKPROBE_SYMBOL(trace_hardirqs_on); +void __trace_hardirqs_off(void) +{ + if (!this_cpu_read(tracing_irq_cpu)) { + this_cpu_write(tracing_irq_cpu, 1); + tracer_hardirqs_off(CALLER_ADDR0, CALLER_ADDR1); + if (!in_nmi()) + trace_irq_disable(CALLER_ADDR0, CALLER_ADDR1); + } + +} +NOKPROBE_SYMBOL(__trace_hardirqs_off); + void trace_hardirqs_off(void) { if (!this_cpu_read(tracing_irq_cpu)) {