Date: Mon, 8 Jun 2015 21:35:14 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Alexander Holler <holler@ahsoftware.de>
Cc: Richard Weinberger <richard.weinberger@gmail.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Tejun Heo <htejun@gmail.com>, Louis Langholtz <lou_langholtz@me.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Trivial patch monkey <trivial@kernel.org>,
        Rusty Russell <rusty@rustcorp.com.au>,
        Andrew Morton <akpm@linux-foundation.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Thomas Gleixner <tglx@linutronix.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH] debug: Deprecate BUG_ON() use in new code, introduce
 CRASH_ON()
Message-ID: <20150608193514.GA13053@gmail.com>
References: <20150608000007.GA3543@mtj.duckdns.org>
 <CA+55aFwmOGaP1DN3frkfP+Df=jCwURqO22A6-5GqpMnZXkvMXA@mail.gmail.com>
 <20150608071215.GA369@gmail.com>
 <557546E6.5030304@ahsoftware.de>
 <CAFLxGvzrSUfEV+LM26yy6aeA7hqGt0PnuuBD6rWDhRnivSRSmQ@mail.gmail.com>
 <5575558E.5070706@ahsoftware.de>
 <20150608090509.GA19160@gmail.com>
 <55755D6F.3030201@ahsoftware.de>
 <20150608112702.GA20511@gmail.com>
 <5575D9C4.50204@ahsoftware.de>
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* Alexander Holler <holler@ahsoftware.de> wrote:

> Am 08.06.2015 um 13:27 schrieb Ingo Molnar:
> >
> >* Alexander Holler <holler@ahsoftware.de> wrote:
> >
> >>>I am pretty certain that Greg would have applied such a patch in an eye blink.
> >>
> >>As you've said it, *probably*. But such a simple exit path as you're proposing
> >>doesn't always exist. [...]
> >
> >As I said it's case by case. I discussed your example (which was a deficient patch
> >for multiple reasons) but we'd be wasting everyone's time by discussion
> >hypothethical situations.
> 
> Sure it was a deficient patch, but still better than what existed for a year 
> long in the kernel [...]

... but it was still worse than the simple solution I suggested:

	if (WARN_ON_ONCE(port->itty))
		return;

again, the BUG_ON() you wanted to introduce was wrong on multiple grounds, then 
and now. Why are you still arguing about this?

> I just want to make clear that a brutforce slogan like BUG_ON is bad is bad,

I pointed out specific cases where a BUG_ON() is the right solution. They are 
rare. Stop misrepresenting my words.

Thanks,

	Ingo
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