From mboxrd@z Thu Jan 1 00:00:00 1970 From: Prarit Bhargava Subject: Re: [PATCH] kernel, add panic_on_warn Date: Mon, 03 Nov 2014 08:32:42 -0500 Message-ID: <545783FA.4050508@redhat.com> References: <1414688627-5298-1-git-send-email-prarit@redhat.com> <20141031015843.GW9743@dangermouse.emea.sgi.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20141031015843.GW9743-2aXy8kx9jd5qWu+OMeiFJmRHvnxUvMa2@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+glkk-kexec=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andi Kleen , Jonathan Corbet , kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Rusty Russell , linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, jbaron-JqFfY2XvxFXQT0dZR+AlfA@public.gmane.org, Fabian Frederick , isimatu.yasuaki-+CUm20s59erQFUHtdCDX3A@public.gmane.org, "H. Peter Anvin" , Masami Hiramatsu , Andrew Morton , linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org List-Id: linux-api@vger.kernel.org On 10/30/2014 09:58 PM, Hedi Berriche wrote: > On Thu, Oct 30, 2014 at 17:06 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. > > Do we want to leave it to usersspace[1] to ensure panic_on_warn is out > of the way in when the kdump kernel boots? or would a self-contained > approach be more preferable i.e. test whether we're a kdump kernel > before bothering with panic_on_warn? Hmm ... this is a good point. Vivek, do you have a preference? I'm willing to code it either way. I should be able to put in a is_kdump_kernel() check without any problems but I'm not sure if that is the right thing to do here. P. > > Cheers, > Hedi. > > [1] kexec-tools in the case of the boot param by filtering it out of the > kdump kernel cmdline. In the case of sysctl.conf, it would depend on > whether there are distros out there that include it in the kdump > initrd. >