From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751162AbdBPFJZ (ORCPT ); Thu, 16 Feb 2017 00:09:25 -0500 Received: from ozlabs.org ([103.22.144.67]:43511 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750728AbdBPFJY (ORCPT ); Thu, 16 Feb 2017 00:09:24 -0500 From: Michael Ellerman To: Pan Xinhui , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Cc: benh@kernel.crashing.org, paulus@samba.org, npiggin@gmail.com, gpiccoli@linux.vnet.ibm.com, Pan Xinhui Subject: Re: [PATCH] powerpc/xmon: Fix an unexpected xmon onoff state change In-Reply-To: <1487144990-5969-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> References: <1487144990-5969-1-git-send-email-xinhui.pan@linux.vnet.ibm.com> User-Agent: Notmuch/0.21 (https://notmuchmail.org) Date: Thu, 16 Feb 2017 16:09:18 +1100 Message-ID: <87shnek9hd.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Pan Xinhui writes: > Once xmon is triggered by sysrq-x, it is enabled always afterwards even > if it is disabled during boot. This will cause a system reset interrut > fail to dump. So keep xmon in its original state after exit. > > Signed-off-by: Pan Xinhui > --- > arch/powerpc/xmon/xmon.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c > index 9c0e17c..721212f 100644 > --- a/arch/powerpc/xmon/xmon.c > +++ b/arch/powerpc/xmon/xmon.c > @@ -76,6 +76,7 @@ static int xmon_gate; > #endif /* CONFIG_SMP */ > > static unsigned long in_xmon __read_mostly = 0; > +static int xmon_off = 0; > > static unsigned long adrs; > static int size = 1; > @@ -3250,6 +3251,8 @@ static void sysrq_handle_xmon(int key) > /* ensure xmon is enabled */ > xmon_init(1); > debugger(get_irq_regs()); > + if (xmon_off) > + xmon_init(0); > } I don't think this is right. xmon_off is only true if you boot with xmon=off on the command line. So if you boot with CONFIG_XMON_DEFAULT=n, and nothing on the command line, then enter xmon via sysrq, then exit, xmon will still be enabled. cheers