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=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 D4377C433E1 for ; Tue, 19 May 2020 19:52:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AC90A207E8 for ; Tue, 19 May 2020 19:52:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727927AbgESTwx (ORCPT ); Tue, 19 May 2020 15:52:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51012 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727853AbgESTws (ORCPT ); Tue, 19 May 2020 15:52:48 -0400 Received: from Galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB22EC08C5C1; Tue, 19 May 2020 12:52:47 -0700 (PDT) Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1jb8I1-0007tD-Kg; Tue, 19 May 2020 21:52:37 +0200 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 2F0D41C047E; Tue, 19 May 2020 21:52:37 +0200 (CEST) Date: Tue, 19 May 2020 19:52:37 -0000 From: "tip-bot2 for Petr Mladek" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: core/rcu] printk: Prepare for nested printk_nmi_enter() Cc: Petr Mladek , "Peter Zijlstra (Intel)" , Thomas Gleixner , Alexandre Chartre , x86 , LKML In-Reply-To: <20200505134100.681374113@linutronix.de> References: <20200505134100.681374113@linutronix.de> MIME-Version: 1.0 Message-ID: <158991795708.17951.10946630610236060760.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit 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: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the core/rcu branch of tip: Commit-ID: 8c4e93c362ff114def211d4629b120af86eb1275 Gitweb: https://git.kernel.org/tip/8c4e93c362ff114def211d4629b120af86eb1275 Author: Petr Mladek AuthorDate: Mon, 24 Feb 2020 13:13:31 +01:00 Committer: Thomas Gleixner CommitterDate: Tue, 19 May 2020 15:51:16 +02:00 printk: Prepare for nested printk_nmi_enter() There is plenty of space in the printk_context variable. Reserve one byte there for the NMI context to be on the safe side. It should never overflow. The BUG_ON(in_nmi() == NMI_MASK) in nmi_enter() will trigger much earlier. Signed-off-by: Petr Mladek Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Reviewed-by: Alexandre Chartre Link: https://lkml.kernel.org/r/20200505134100.681374113@linutronix.de --- kernel/printk/internal.h | 8 +++++--- kernel/printk/printk_safe.c | 4 ++-- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h index b2b0f52..660f9a6 100644 --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h @@ -6,9 +6,11 @@ #ifdef CONFIG_PRINTK -#define PRINTK_SAFE_CONTEXT_MASK 0x3fffffff -#define PRINTK_NMI_DIRECT_CONTEXT_MASK 0x40000000 -#define PRINTK_NMI_CONTEXT_MASK 0x80000000 +#define PRINTK_SAFE_CONTEXT_MASK 0x007ffffff +#define PRINTK_NMI_DIRECT_CONTEXT_MASK 0x008000000 +#define PRINTK_NMI_CONTEXT_MASK 0xff0000000 + +#define PRINTK_NMI_CONTEXT_OFFSET 0x010000000 extern raw_spinlock_t logbuf_lock; diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c index d9a659a..e8791f2 100644 --- a/kernel/printk/printk_safe.c +++ b/kernel/printk/printk_safe.c @@ -295,12 +295,12 @@ static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args) void notrace printk_nmi_enter(void) { - this_cpu_or(printk_context, PRINTK_NMI_CONTEXT_MASK); + this_cpu_add(printk_context, PRINTK_NMI_CONTEXT_OFFSET); } void notrace printk_nmi_exit(void) { - this_cpu_and(printk_context, ~PRINTK_NMI_CONTEXT_MASK); + this_cpu_sub(printk_context, PRINTK_NMI_CONTEXT_OFFSET); } /*