From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from terminus.zytor.com ([2001:1868:205::10] helo=mail.zytor.com) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1XjtT6-0005Rd-FU for kexec@lists.infradead.org; Thu, 30 Oct 2014 17:25:06 +0000 Message-ID: <54527443.6030007@zytor.com> Date: Thu, 30 Oct 2014 10:24:19 -0700 From: "H. Peter Anvin" MIME-Version: 1.0 Subject: Re: [PATCH] kernel, add panic_on_warn References: <1414688627-5298-1-git-send-email-prarit@redhat.com> In-Reply-To: <1414688627-5298-1-git-send-email-prarit@redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Prarit Bhargava , linux-kernel@vger.kernel.org Cc: Andi Kleen , Jonathan Corbet , kexec@lists.infradead.org, Rusty Russell , linux-doc@vger.kernel.org, jbaron@akamai.com, Fabian Frederick , isimatu.yasuaki@jp.fujitsu.com, linux-api@vger.kernel.org, Masami Hiramatsu , Andrew Morton , vgoyal@redhat.com On 10/30/2014 10:03 AM, Prarit Bhargava wrote: > There have been several times where I have had to rebuild a kernel to > cause a panic when hitting a WARN() in the code in order to get a crash > dump from a system. Sometimes this is easy to do, other times (such as > in the case of a remote admin) it is not trivial to send new images to the > user. > > A much easier method would be a switch to change the WARN() over to a > panic. This makes debugging easier in that I can now test the actual > image the WARN() was seen on and I do not have to engage in remote > debugging. > > This patch adds a panic_on_warn kernel parameter and > /proc/sys/kernel/panic_on_warn calls panic() in the warn_slowpath_common() > path. The function will still print out the location of the warning. > > An example of the panic_on_warn output: > > The first line below is from the WARN_ON() to output the WARN_ON()'s location. > After that the panic() output is displayed. > There is another very valid use for this: many operators would rather a machine shuts down than being potentially compromised either functionally or security-wise. -hpa _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec