From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751521Ab3KRXNn (ORCPT ); Mon, 18 Nov 2013 18:13:43 -0500 Received: from prod-mail-xrelay07.akamai.com ([72.246.2.115]:38086 "EHLO prod-mail-xrelay07.akamai.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751307Ab3KRXNl (ORCPT ); Mon, 18 Nov 2013 18:13:41 -0500 Message-ID: <528A9F24.1000206@akamai.com> Date: Mon, 18 Nov 2013 18:13:40 -0500 From: Jason Baron User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130330 Thunderbird/17.0.5 MIME-Version: 1.0 To: Andrew Morton CC: "mingo@kernel.org" , "benh@kernel.crashing.org" , "paulus@samba.org" , "ralf@linux-mips.org" , "linux-kernel@vger.kernel.org" , Felipe Contreras Subject: Re: [PATCH v2] panic: Make panic_timeout configurable References: <20131118210436.233B5202A@prod-mail-relay06.akamai.com> <20131118143059.afe17d2faced16171a05eb10@linux-foundation.org> In-Reply-To: <20131118143059.afe17d2faced16171a05eb10@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/18/2013 05:30 PM, Andrew Morton wrote: > On Mon, 18 Nov 2013 21:04:36 +0000 (GMT) Jason Baron wrote: > >> The panic_timeout value can be set via the command line option 'panic=x', or via >> /proc/sys/kernel/panic, however that is not sufficient when the panic occurs >> before we are able to set up these values. Thus, add a CONFIG_PANIC_TIMEOUT >> so that we can set the desired value from the .config. >> >> The default panic_timeout value continues to be 0 - wait forever, except for >> powerpc and mips, which have been defaulted to 180 and 5 respectively. This >> is in keeping with the fact that these arches already set panic_timeout in >> their arch init code. However, I found three exceptions- two in mips and one in >> powerpc where the settings didn't match these default values. In those cases, I >> left the arch code so it continues to override, in case the user has not changed >> from the default. It would nice if these arches had one default value, or if we >> could determine the correct setting at compile-time. > > Felipe is proposing a simpler patch ("panic: setup panic_timeout > early") which switches to early_param(). Is that sufficient for the > (undescribed!) failure which you are presumably observing? > No - that patch doesn't change the 'panic_timeout' value until the call to 'parse_early_param()' is made. If there is a panic before that point, the param doesn't do anything. The idea of this patch is to allow it to be configured at build-time. I've tested the patch by simply inserting a panic() call at the beginning of 'start_kernel()'. So, no I do not have a specific panic in mind for this. Thanks, -Jason