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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 55577C433E4 for ; Tue, 30 Mar 2021 15:36:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1DBAE61A08 for ; Tue, 30 Mar 2021 15:36:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232535AbhC3Pfj (ORCPT ); Tue, 30 Mar 2021 11:35:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59844 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232068AbhC3PfY (ORCPT ); Tue, 30 Mar 2021 11:35:24 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6BC3EC061574 for ; Tue, 30 Mar 2021 08:35:18 -0700 (PDT) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1617118514; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=YPYdY00O6y5AyCUxqpuYCSP5+y//XPdG6L9507cj5Ic=; b=qQDflIkAz51LrvGLUrPwJwlERwWmT6hRYLbUtz0Trgd18/qLrOCW3YJxVb2jNAurM81TyI 3AsXxivkW9AuZRb35RUNhV/DFicFLJm/ny52MZHlxV7nYaB82D7yRtI4eJOR3/A6GZI+4W Oj90Fp+qLdueXya9Nqaj7zUEgUAq3I566RihuuDiupy7dG0M1LBtHXzJHIUGFj2fBotjoc m2sdVo64AJACocszlTWXWkB3zjWrA7HaH4WgN9u85YOkFnQ/JYc9BcjSaehTMGu0Tieka6 Qum9ld/CWbuBmTjG8QIJS2kuF/+SwuV/YneE4CHchkQF8b8DmaCwDpcuT+u3QQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1617118514; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=YPYdY00O6y5AyCUxqpuYCSP5+y//XPdG6L9507cj5Ic=; b=DAWOFKfBAuSGqLOlxY962SnoWviQuD0AGtEm319HtzpL33OlIzgLcrRMou9nKTPDT+oWj6 VfRxVIoORXq20wCQ== To: Petr Mladek Cc: Sergey Senozhatsky , Sergey Senozhatsky , Steven Rostedt , Thomas Gleixner , linux-kernel@vger.kernel.org, Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Eric Biederman , Christophe Leroy , Nicholas Piggin , Alistair Popple , Jordan Niethe , Peter Zijlstra , "Aneesh Kumar K.V" , Andrew Morton , Kees Cook , Tiezhu Yang , Alexey Kardashevskiy , Yue Hu , Rafael Aquini , "Guilherme G. Piccoli" , "Paul E. McKenney" , linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org, Russell King , Ingo Molnar , Marc Zyngier , Valentin Schneider , Mike Rapoport , Geert Uytterhoeven , Anshuman Khandual , Leonardo Bras , Andy Lutomirski , Will Deacon , Frederic Weisbecker , Masahiro Yamada , Nathan Chancellor , Alexei Starovoitov , Nick Terrell , David Howells , Johannes Weiner , linux-arm-kernel@lists.infradead.org Subject: [PATCH printk v2 0/5] printk: remove safe buffers Date: Tue, 30 Mar 2021 17:35:07 +0200 Message-Id: <20210330153512.1182-1-john.ogness@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Here is v2 of a series to remove the safe buffers. v1 can be found here [0]. The safe buffers are no longer needed because messages can be stored directly into the log buffer from any context. However, the safe buffers also provided a form of recursion protection. For that reason, explicit recursion protection is also implemented for this series. And finally, with the removal of the safe buffers, there is no need for extra NMI enter/exit tracking. So this is also removed (which includes removing config option CONFIG_PRINTK_NMI). This series is based on the printk-rework branch of printk/linux.git: commit acebb5597ff1 ("kernel/printk.c: Fixed mundane typos") Changes since v1: - remove the printk nmi enter/exit tracking - remove CONFIG_PRINTK_NMI config option - use in_nmi() to detect NMI context - remove unused printk_safe_enter/exit macros - after switching to the dynamic buffer, copy over NMI records that may have arrived during the switch window - use local_irq_*() instead of printk_safe_*() for console spinning - use separate variables rather than arrays for the per-cpu recursion tracking - make @syslog_lock a mutex instead of a spin_lock - close the wait-read window for SYSLOG_ACTION_READ - adjust various comments and commit messages as requested John Ogness [0] https://lore.kernel.org/lkml/20210316233326.10778-1-john.ogness@linutronix.de John Ogness (5): printk: track/limit recursion printk: remove safe buffers printk: remove NMI tracking printk: convert @syslog_lock to mutex printk: syslog: close window between wait and read arch/arm/kernel/smp.c | 2 - arch/powerpc/kernel/traps.c | 1 - arch/powerpc/kernel/watchdog.c | 5 - arch/powerpc/kexec/crash.c | 3 - include/linux/hardirq.h | 2 - include/linux/printk.h | 22 -- init/Kconfig | 5 - kernel/kexec_core.c | 1 - kernel/panic.c | 3 - kernel/printk/internal.h | 23 --- kernel/printk/printk.c | 281 +++++++++++++++---------- kernel/printk/printk_safe.c | 362 +-------------------------------- kernel/trace/trace.c | 2 - lib/nmi_backtrace.c | 6 - 14 files changed, 171 insertions(+), 547 deletions(-) -- 2.20.1