Received: by 2002:a05:7412:bbc7:b0:fc:a2b0:25d7 with SMTP id kh7csp102026rdb; Thu, 1 Feb 2024 03:29:48 -0800 (PST) X-Google-Smtp-Source: AGHT+IGwJFLmmDO9gHTq48G/fjtB7IyrnvG3fx9PZ5VJhZjHkg2TLtjtiTuD9A4dbnzfkkErL8uN X-Received: by 2002:a50:9e25:0:b0:55f:335:8b77 with SMTP id z34-20020a509e25000000b0055f03358b77mr3232393ede.39.1706786988707; Thu, 01 Feb 2024 03:29:48 -0800 (PST) ARC-Seal: i=2; a=rsa-sha256; t=1706786988; cv=pass; d=google.com; s=arc-20160816; b=Ts29dnpSNkceQJ7zIRRUBNT4W+dHF/XcQAhc71KlBUBof4gcXANjDybNl9oImFmb62 4gmSA4Cjq/J/lfvIx9Jinrthv77XH7TkqjUPKdDYqC2Vfh7eIs3oiB1S1a5NvNfUBYH6 U3JwlsYXuSrVzbJ0z7d1lMOifGvVIdz1avogvovwKLrCgvs+5dXOJIhDAl/xwvwJWLy/ dLWw+AaxR6u7vc463AS7hJd9jofvdSqwaXUamodJPzRbP4TNwTf7RgZaZhSFaqUrIm9u VXkYPTilJaPOamIkJJ3lfZUaqtB2eHN5XaC7snhRRyBobHqHK5Lc8EeSDvgyTIGaBGqd saVw== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:list-unsubscribe:list-subscribe:list-id:precedence :message-id:date:references:in-reply-to:subject:cc:to:dkim-signature :dkim-signature:from; bh=N59cteCuM1gkkOQNHLFLkmRsPXR1qrb8VkKrOroB6Ts=; fh=ScyR61ErlYR9RJlQxRDoOOwd6uGVR3PuKnsvRFdgEZw=; b=SsZj0wzB3FuG07Bn37D261Do+y/DIWbmMmH2UHjrLDbL/t3H+AEySqzQBUquWgBGgF k51WQaT/D1SLaUjWaJ0GbFZl2fArgI81quJkQoVH1g6ve0z76+Hpd3iqwXcczNsskLeO 8x7NjE2W3cueNWKsQ8AL4ryvmlay+ohAtM+5bHbcK2WUL4ve8qPy9kng8SW1VInnhJTB VYlVNcY86KmVKg9L8RntSEztyiPZa6XBxS6VRTXMFKzQzJs8UxG2679TfZhWpmK0l9yO oaNi1jEYgEvQ00436XgovVRvAHuPgqkMUrp2dRV7Bcmb9FRABihtJXlWoyJ2DIOhwoye uZjg==; dara=google.com ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@linutronix.de header.s=2020 header.b=grd+BLvC; dkim=neutral (no key) header.i=@linutronix.de header.s=2020e; arc=pass (i=1 spf=pass spfdomain=linutronix.de dkim=pass dkdomain=linutronix.de dmarc=pass fromdomain=linutronix.de); spf=pass (google.com: domain of linux-kernel+bounces-48012-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-48012-linux.lists.archive=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=linutronix.de X-Forwarded-Encrypted: i=1; AJvYcCXc8e4k6TicOqYOrCaCOP7hIKHlONTTCiOpPi68xONrkcoWWKPmj1O40/l65sNZDb6dKxkc/rL+nT0B13bjsPNBkfyX2oC/K02vBi61OA== Return-Path: Received: from am.mirrors.kernel.org (am.mirrors.kernel.org. [2604:1380:4601:e00::3]) by mx.google.com with ESMTPS id x8-20020a50ba88000000b0055f2ce1d20fsi3314475ede.632.2024.02.01.03.29.48 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Feb 2024 03:29:48 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-48012-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3; Authentication-Results: mx.google.com; dkim=pass header.i=@linutronix.de header.s=2020 header.b=grd+BLvC; dkim=neutral (no key) header.i=@linutronix.de header.s=2020e; arc=pass (i=1 spf=pass spfdomain=linutronix.de dkim=pass dkdomain=linutronix.de dmarc=pass fromdomain=linutronix.de); spf=pass (google.com: domain of linux-kernel+bounces-48012-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) smtp.mailfrom="linux-kernel+bounces-48012-linux.lists.archive=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=linutronix.de Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by am.mirrors.kernel.org (Postfix) with ESMTPS id 748AE1F2727D for ; Thu, 1 Feb 2024 11:29:48 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A143615CD73; Thu, 1 Feb 2024 11:29:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="grd+BLvC"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="t4zdW6qw" Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CF09C15B970; Thu, 1 Feb 2024 11:29:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706786980; cv=none; b=W1JyD+0nF0lOK/x3/4TtK4dNv54jQTnWxyru8Kbl8xS+GTiwzgPX23QPkznqf6XIRZXKXRucXlbW5K7kHAbv/hHyare9cWomjaby1nNU0XywLeaivu6TX2tbpk/TQfnePsyNg27QFmD5xImhxfYSfvVOYNOfQLOtYVhNqBTMmKI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706786980; c=relaxed/simple; bh=N59cteCuM1gkkOQNHLFLkmRsPXR1qrb8VkKrOroB6Ts=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=hfRiRPhPhwceVvEH22PJT4OqEugbnoD6KPoc+WUnR+21Wp4q73En8LBvLSFTAdWdMOSn3SJc00YeW3casrbGP/am3NI5Bubk7SJBlPjpcg1SbAyay9SEvFGQ+fgsw77+VMtH1G9/QMeVoIo41nxpv61W5+UbIon1hbKsIPScFmk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=grd+BLvC; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=t4zdW6qw; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1706786977; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=N59cteCuM1gkkOQNHLFLkmRsPXR1qrb8VkKrOroB6Ts=; b=grd+BLvCowvUE3ckE2wROp99t208zMWjwFjvBix+xxYku8ZyCJXO1knDbBZ+Yyp564SX6z sr3DXocSnsJeeT8Dwyw/gdgB0JOvLVgPSE9IaIA06HVd2D4T7v7j1sQCvBYRep/HmnqF0w n5tzZda5xOZxrrgcCUlG8nhV0M4uVFQAlpzk3CVZ5PeVwLWkzMu7+H3iHZ1UTC+AemcbIv 58VlK/SEhN5HwvKz/6lMD7eDSecO1lb5kVKestqlGJmN7u4MRbH30AKMmWvb8kax77mZ/f D8UEMvH2aIZM9oFIodaIthYb6u+KPeHEm0s3TwRu+KKhpI01zkIKFmyt3IBx7A== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1706786977; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=N59cteCuM1gkkOQNHLFLkmRsPXR1qrb8VkKrOroB6Ts=; b=t4zdW6qwJiYwX+e/kJfaEnHLE1cgxAqy2onSxSJxCqPJIyAa5scnvJqqYGK+2SqXcJOx1n ix3UiuxD8Pagt6CQ== To: Sreenath Vijayan , corbet@lwn.net, gregkh@linuxfoundation.org, jirislaby@kernel.org, pmladek@suse.com Cc: rdunlap@infradead.org, rostedt@goodmis.org, senozhatsky@chromium.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, taichi.shimoyashiki@sony.com, daniel.palmer@sony.com, anandakumar.balasubramaniam@sony.com, sreenath.vijayan@sony.com Subject: Re: [PATCH v4 2/2] tty/sysrq: Dump printk ring buffer messages via sysrq In-Reply-To: References: Date: Thu, 01 Feb 2024 12:35:32 +0106 Message-ID: <87plxgo21v.fsf@jogness.linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On 2024-02-01, Sreenath Vijayan wrote: > When terminal is unresponsive, one cannot use dmesg to view printk > ring buffer messages. Also, syslog services may be disabled, > to check the messages after a reboot, especially on embedded systems. > In this scenario, dump the printk ring buffer messages via sysrq > by pressing sysrq+D. > > Signed-off-by: Sreenath Vijayan > Signed-off-by: Shimoyashiki Taichi Reviewed-by: John Ogness