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SubjectRe: [PATCH v2 10/11] watchdog/hpwdt: remove allow_kdump module parameter.
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 <jerry.hoemann@hpe.com>
> ---
> 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
>
> --
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