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From: Steven Rostedt <rostedt@goodmis.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	Dmitry Vyukov <dvyukov@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Matthew Garrett <mjg59@google.com>,
	Andi Kleen <ak@linux.intel.com>,
	"Theodore Y . Ts'o" <tytso@mit.edu>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Petr Mladek <pmladek@suse.com>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Arnd Bergmann <arnd@arndb.de>, Jiri Slaby <jslaby@suse.com>,
	Peter Zijlstra <peterz@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3] Add kernel config option for tweaking kernel behavior.
Date: Tue, 14 Apr 2020 21:43:01 -0400	[thread overview]
Message-ID: <20200414214301.126ada20@oasis.local.home> (raw)
In-Reply-To: <CAHk-=wjLfHaF8F-L9axpYcNtECa=Rw_LWJ98GP6ByUB+O98tAQ@mail.gmail.com>

On Tue, 14 Apr 2020 18:14:51 -0700
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> If that WARN_ON() is a problem, then the people behind it should be
> appraised of it, and it should probably be removed. I'm assuming it
> was some kind of "I don't think this can happen, so if it does, I want
> to see how it happened" WARN_ON.

What I do (and feel everyone should too), is I only add a WARN_ON()
when I check something that I believe *can't* happen. If the WARN_ON()
triggers, it either means that there's a bug in the code (and needs a
fix), or the code design changed, in which case the WARN_ON() should be
either removed, or that code updated to handle the new change.

In any case, a WARN_ON() should always be investigated when hit.

The only time I've had issues with people is when I have some hardware
(i915) that triggers a WARN_ON() and I'm told that my hardware is buggy
(or I need a firmware update). In which case, I just manually remove
the WARN_ON() because the machine that triggers it is a test machine I
don't have the time to waste updating firmware on.

-- Steve

  reply	other threads:[~2020-04-15  1:43 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-13  6:33 Tetsuo Handa
2020-04-13  8:14 ` Greg Kroah-Hartman
2020-04-18 14:28   ` Tetsuo Handa
2020-04-18 14:39     ` Greg Kroah-Hartman
2020-04-18 15:08       ` Tetsuo Handa
2020-04-13 18:13 ` Linus Torvalds
2020-04-14  8:02   ` Tetsuo Handa
2020-04-15  0:05     ` Tetsuo Handa
2020-04-15  1:14       ` Linus Torvalds
2020-04-15  1:43         ` Steven Rostedt [this message]
2020-04-16  0:47   ` Tetsuo Handa

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