From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753220Ab2AWPJS (ORCPT ); Mon, 23 Jan 2012 10:09:18 -0500 Received: from mx1.redhat.com ([209.132.183.28]:32141 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752899Ab2AWPJR (ORCPT ); Mon, 23 Jan 2012 10:09:17 -0500 Date: Mon, 23 Jan 2012 16:03:09 +0100 From: Oleg Nesterov To: Denys Vlasenko Cc: linux-kernel@vger.kernel.org, Andrew Morton Subject: Re: [PATCH v2] If init dies, log a signal which killed it, if any. Message-ID: <20120123150309.GA8153@redhat.com> References: <1327097836-8485-1-git-send-email-vda.linux@googlemail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1327097836-8485-1-git-send-email-vda.linux@googlemail.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/20, Denys Vlasenko wrote: > > I just received another user's pleas for help when their > init mysteriously died. I again explained that they need to check > whether it died because of bad instruction, a segv, or something else. > Which was an annoying detour into writing a trivial C program > to spawn his init and print its exit code: > > http://lists.busybox.net/pipermail/busybox/2012-January/077172.html > > I hear you saying "just test it under /bin/sh". Well, the crashing init > _was_ /bin/sh. > > Which prompted me to make kernel do this first step automatically. > We can print exit code, which makes it possible to see that > death was from e.g. SIGILL without writing test programs. > > The code is fairly self-explanatory. Compile-tested. > > Changes in v.2: don't try to decode signal names, just print > exit status in hex. Looks reasonable to me. Probably you should re-send the patch to Andrew, I do not know who else can pick it. Acked-by: Oleg Nesterov > Signed-off-by: Denys Vlasenko > --- > kernel/exit.c | 7 +++++-- > 1 files changed, 5 insertions(+), 2 deletions(-) > > diff --git a/kernel/exit.c b/kernel/exit.c > index 294b170..0c540a5 100644 > --- a/kernel/exit.c > +++ b/kernel/exit.c > @@ -710,8 +710,11 @@ static struct task_struct *find_new_reaper(struct task_struct *father) > > if (unlikely(pid_ns->child_reaper == father)) { > write_unlock_irq(&tasklist_lock); > - if (unlikely(pid_ns == &init_pid_ns)) > - panic("Attempted to kill init!"); > + if (unlikely(pid_ns == &init_pid_ns)) { > + panic("Attempted to kill init! exitcode=%08x\n", > + father->signal->group_exit_code ?: > + father->exit_code); > + } > > zap_pid_ns_processes(pid_ns); > write_lock_irq(&tasklist_lock); > -- > 1.7.7.5 >