From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 6407379948; Thu, 21 Dec 2023 23:12:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="J8Gnd+0L" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Sender:Reply-To:Content-ID:Content-Description; bh=ysJ1nRhQ8xLtmwMxQM54I2ikdSeFGYHpjXOSTY91G18=; b=J8Gnd+0L4FdQ46ayKLbY8F1mRr stnhlQXCh44liIcKVvKA+RviYLAg4Pm1mRS11Q+WdWI7W4MT+uictfzcIR4/QKaveSlGhSmbS6ZQt VTxy+JnaQm3o1bHDi0uDT/85SetX4L62gJJ5ZxB/Q6A1k9kIJkH2fx149ZY3zmDWLTUdFDH1FO/2X IVxnjvfbIV6qJLexwrkQZl8Z9U9UnJY0sGDE131rNKnLVaIr4poY6BXIyvA+Ltp1uDNc7mLADGxNl FQ/84Zsd8Gva9Hbd0NqHcR54EmJOAjDIJmohL6jefF2txFePiS5VQX7kdOr7OpAcxZJnkSV4NL/p6 ko0Iy1wQ==; Received: from [50.53.46.231] (helo=[192.168.254.15]) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1rGSDh-004Ous-0x; Thu, 21 Dec 2023 23:12:49 +0000 Message-ID: Date: Thu, 21 Dec 2023 15:12:46 -0800 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] tty/sysrq: Dump kernel ring buffer messages via sysrq Content-Language: en-US To: Greg KH , Sreenath Vijayan Cc: linux-doc@vger.kernel.org, linux-serial@vger.kernel.org, corbet@lwn.net, jirislaby@kernel.org, linux-kernel@vger.kernel.org, anandakumar.balasubramaniam@sony.com, Shimoyashiki Taichi References: <20231221133953.1507021-1-sreenath.vijayan@sony.com> <2023122144-enlarged-maggot-493a@gregkh> From: Randy Dunlap In-Reply-To: <2023122144-enlarged-maggot-493a@gregkh> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 12/21/23 08:52, Greg KH wrote: > On Thu, Dec 21, 2023 at 07:09:53PM +0530, Sreenath Vijayan wrote: >> When terminal is unresponsive, one cannot use dmesg to view kernel >> ring buffer messages. Also, syslog services may be disabled, >> to check them after a reboot, especially on embedded systems. >> In this scenario, dump the kernel ring buffer messages via sysrq >> by pressing sysrq+D. >> >> Signed-off-by: Sreenath Vijayan >> Signed-off-by: Shimoyashiki Taichi >> --- >> Documentation/admin-guide/sysrq.rst | 2 ++ >> drivers/tty/sysrq.c | 43 ++++++++++++++++++++++++++++- >> 2 files changed, 44 insertions(+), 1 deletion(-) >> >> diff --git a/Documentation/admin-guide/sysrq.rst b/Documentation/admin-guide/sysrq.rst >> index 2f2e5bd440f9..464c4e138b9d 100644 >> --- a/Documentation/admin-guide/sysrq.rst >> +++ b/Documentation/admin-guide/sysrq.rst >> @@ -161,6 +161,8 @@ Command Function >> will be printed to your console. (``0``, for example would make >> it so that only emergency messages like PANICs or OOPSes would >> make it to your console.) >> + >> +``D`` Dump the kernel ring buffer >> =========== =================================================================== > > Nit, this doesn't line up anymore :( Yes, that will cause a docs build warning. Also, can you be more explicit about which ring buffer this patch is referring to, please. -- #Randy https://people.kernel.org/tglx/notes-about-netiquette https://subspace.kernel.org/etiquette.html