From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752709AbbCEWT7 (ORCPT ); Thu, 5 Mar 2015 17:19:59 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43038 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750919AbbCEWT6 (ORCPT ); Thu, 5 Mar 2015 17:19:58 -0500 Date: Thu, 5 Mar 2015 17:19:30 -0500 From: Vivek Goyal To: HATAYAMA Daisuke Cc: ebiederm@xmission.com, masami.hiramatsu.pt@hitachi.com, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, bhe@redhat.com, hidehiro.kawai.ez@hitachi.com Subject: Re: [RESEND PATCH] kernel/panic/kexec: fix "crash_kexec_post_notifiers" option issue in oops path Message-ID: <20150305221930.GC22336@redhat.com> References: <20150304.175648.86711471.d.hatayama@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150304.175648.86711471.d.hatayama@jp.fujitsu.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 04, 2015 at 05:56:48PM +0900, HATAYAMA Daisuke wrote: > The commit f06e5153f4ae2e2f3b0300f0e260e40cb7fefd45 introduced > "crash_kexec_post_notifiers" kernel boot option, which toggles > wheather panic() calls crash_kexec() before or after panic_notifiers > and dump kmsg. > > The problem is that the commit overlooks panic_on_oops kernel boot > option. If it is enabled, crash_kexec() is called directly without > going through panic() in oops path. > > To fix this issue, this patch adds a check to > "crash_kexec_post_notifiers" in the condition of kexec_should_crash(). > > Signed-off-by: HATAYAMA Daisuke > Acked-by: Baoquan He > Tested-by: Hidehiro Kawai > --- > include/linux/kernel.h | 3 +++ > kernel/kexec.c | 2 ++ > kernel/panic.c | 2 +- > 3 files changed, 6 insertions(+), 1 deletion(-) > > diff --git a/include/linux/kernel.h b/include/linux/kernel.h > index 64ce58b..f47379f 100644 > --- a/include/linux/kernel.h > +++ b/include/linux/kernel.h > @@ -426,6 +426,9 @@ extern int panic_on_unrecovered_nmi; > extern int panic_on_io_nmi; > extern int panic_on_warn; > extern int sysctl_panic_on_stackoverflow; > + > +extern bool crash_kexec_post_notifiers; > + > /* > * Only to be used by arch init code. If the user over-wrote the default > * CONFIG_PANIC_TIMEOUT, honor it. > diff --git a/kernel/kexec.c b/kernel/kexec.c > index 9a8a01a..0ecf252 100644 > --- a/kernel/kexec.c > +++ b/kernel/kexec.c > @@ -84,6 +84,8 @@ struct resource crashk_low_res = { > > int kexec_should_crash(struct task_struct *p) > { > + if (crash_kexec_post_notifiers) > + return 0; This is little confusing. So if crash_kexec_post_notifiers is set but panic_on_oops is not set, still we will return? Should we do this only if panic_on_oops is set? IOW, how about following if (panic_on_oops && crash_kexec_post_notifiers) return 0; And then also put a comment explaining the rationale. Thanks Vivek > if (in_interrupt() || !p->pid || is_global_init(p) || panic_on_oops) > return 1; > return 0; > diff --git a/kernel/panic.c b/kernel/panic.c > index 4d8d6f9..6582546 100644 > --- a/kernel/panic.c > +++ b/kernel/panic.c > @@ -32,7 +32,7 @@ static unsigned long tainted_mask; > static int pause_on_oops; > static int pause_on_oops_flag; > static DEFINE_SPINLOCK(pause_on_oops_lock); > -static bool crash_kexec_post_notifiers; > +bool crash_kexec_post_notifiers; > int panic_on_warn __read_mostly; > > int panic_timeout = CONFIG_PANIC_TIMEOUT; > -- > 1.9.3 >