linux-kernel - Re: [PATCH RFC] Watchdog: sbsa

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Message-ID: <5728BE1B.5010904@codeaurora.org>
Date:	Tue, 3 May 2016 10:04:59 -0500
From:	Timur Tabi <timur@...eaurora.org>
To:	Guenter Roeck <linux@...ck-us.net>,
	Pratyush Anand <panand@...hat.com>
Cc:	fu.wei@...aro.org, Suravee.Suthikulpanit@....com, wim@...ana.be,
	linux-arm-kernel@...ts.infradead.org,
	linux-watchdog@...r.kernel.org,
	open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RFC] Watchdog: sbsa_gwdt: Enhance timeout range

Guenter Roeck wrote:
>> Most likely it will not be corrupted. But, if ISR has been called it
>> means
>> something went wrong, and watchdog was not kicked for the time
>> programmed as
>> "timeout". So, probably we should be extra careful.
>>
> This logic would apply to _every_ watchdog driver implementing interrupts.
> Actually, it would apply to _all_ kernel code, and the logic could be used
> to introduce hyper-defensive programming all over the place, bloat the
> kernel
> and ultimately make it all but unusable. I do not believe in such
> programming
> in an operating system kernel.
>
> On top of that, the assumption that the kernel would be still sane enough
> to call the interrupt handler, but not sane enough to actually execute it,
> seems to be a bit far-fetched.

Agreed.  Pratyush, have you ever seen any watchdog register get 
corrupted, like you describe?  It just seems like you're imagining a 
problem that has never occurred.

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