From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965453AbeBMSUq (ORCPT ); Tue, 13 Feb 2018 13:20:46 -0500 Received: from mail-pl0-f68.google.com ([209.85.160.68]:47045 "EHLO mail-pl0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965286AbeBMSUo (ORCPT ); Tue, 13 Feb 2018 13:20:44 -0500 X-Google-Smtp-Source: AH8x226ZsNbsqALQKHNwgMVYBXS+KC5+UBv7HA8GteqbNeBoYTUuv+sRrGoN0yAsvJQzCHTTFXXZ3Q== Date: Tue, 13 Feb 2018 10:20:42 -0800 From: Guenter Roeck To: Jerry Hoemann Cc: wim@linux-watchdog.org, linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org, rwright@hpe.com, maurice.a.saldivar@hpe.com Subject: Re: [PATCH v2 10/11] watchdog/hpwdt: remove allow_kdump module parameter. Message-ID: <20180213182042.GA26558@roeck-us.net> References: <20180212052111.12010-1-jerry.hoemann@hpe.com> <20180212052111.12010-11-jerry.hoemann@hpe.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180212052111.12010-11-jerry.hoemann@hpe.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Feb 11, 2018 at 10:21:10PM -0700, Jerry Hoemann wrote: > The intent of this parameter is unclear and it sets up a > race between the reset of the system by ASR and crashdump. > > The length of time between receipt of the pretimeout NMI > and the ASR reset of the system is fixed by hardware. > > Turning the parameter off doesn't necessairly prevent a crash dump. > Also, having the ASR reset occur while the system is crash dumping > doesn't imply that the dump was hung given the short duration > between the NMI and the reset. > > This parameter is not a substitute for having a architected watchdog > crashdump hang detection paridigm. > > Signed-off-by: Jerry Hoemann > --- > drivers/watchdog/hpwdt.c | 7 +------ > 1 file changed, 1 insertion(+), 6 deletions(-) > > diff --git a/drivers/watchdog/hpwdt.c b/drivers/watchdog/hpwdt.c > index e9e54fe20804..bb0dcc8709b8 100644 > --- a/drivers/watchdog/hpwdt.c > +++ b/drivers/watchdog/hpwdt.c > @@ -33,7 +33,6 @@ > static unsigned int soft_margin = DEFAULT_MARGIN; /* in seconds */ > static bool nowayout = WATCHDOG_NOWAYOUT; > #ifdef CONFIG_HPWDT_NMI_DECODING > -static unsigned int allow_kdump = 1; At the end of hpwdt_init_nmi_decoding(), there used to be a log message showing the value of allow_kdump. Maybe that was removed in another patch, but it really belongs to this patch, or am I missing something ? Guenter > static bool pretimeout = 1; > #else > static bool pretimeout; > @@ -149,8 +148,7 @@ static int hpwdt_pretimeout(unsigned int ulReason, struct pt_regs *regs) > if (iLO5 && (ulReason == NMI_UNKNOWN) && !mynmi) > return NMI_DONE; > > - if (allow_kdump) > - hpwdt_stop(&hpwdt_dev); > + hpwdt_stop(&hpwdt_dev); > > panic_msg[0] = hexdigit((mynmi>>4)&0xf); > panic_msg[1] = hexdigit(mynmi&0xf); > @@ -351,9 +349,6 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" > __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); > > #ifdef CONFIG_HPWDT_NMI_DECODING /* { */ > -module_param(allow_kdump, int, 0444); > -MODULE_PARM_DESC(allow_kdump, "Start a kernel dump after NMI occurs"); > - > module_param(pretimeout, bool, 0444); > MODULE_PARM_DESC(pretimeout, "Watchdog pretimeout enabled"); > #endif /* } */ > -- > 2.13.6 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html