[PATCH] watchdog: make open-close-open functionality a config knob

[Rasmus Villemoes]

On 15/03/2021 12.16, deweloper at wp.pl wrote:
> Dnia 2021-03-15, o godz. 09:03:07

> 
> It seems that the open-write-close-open sequence has been introduced in busybox 1.28.0 by commit https://git.busybox.net/busybox/commit/?h=31c765081dc41f158786545fbea9294be4685bd2

Yeah, I could probably have spelled that out; I did cc the author of
that commit.

> AFAIU the commit message says that it is a kind of a workaround for some possible implementations of hardware watchdogs, which could enter wrong state when their supervisor in userspace is restarted (confused by close/open? I don't know). But it doesn't name any single example of an existing watchdog like that.
> 
> In my case (softdog nowayout=1) that "fix" only adds:
> - bloat to busybox, and
> - annoying critical error message from kernel (yes, "watchdog: watchdog0: watchdog did not stop!" is at KERN_CRIT level)
> 
> So I'm definitely for making the behaviour introduced by commit 31c765081dc41f158786545fbea9294be4685bd2 optional.

Thanks.

Rasmus