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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
	Antonio SJ Musumeci <trapexit@spawn.link>,
	Miklos Szeredi <miklos@szeredi.hu>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	stable <stable@vger.kernel.org>
Subject: Re: BUG_ON() in workingset_node_shadows_dec() triggers
Date: Mon, 3 Oct 2016 21:12:48 -0700	[thread overview]
Message-ID: <CA+55aFy6a8BVWtqgeJKZuhU-CZFVZ3X90SdQ5z+NTDDsEOnpJA@mail.gmail.com> (raw)
In-Reply-To: <20161003210729.e4c39a86b8e8e4d103715c7d@linux-foundation.org>

On Mon, Oct 3, 2016 at 9:07 PM, Andrew Morton <akpm@linux-foundation.org> wrote:
>
> Well, it's a VM_BUG_ON and few people run with CONFIG_DEBUG_VM.

Ehh. If by "few people" you mean "pretty much everybody", you'd be
right, but your choice of wording would be somewhat misleading,
wouldn't you say?

Hint: here's a line from the standard Fedora kernel config:

    CONFIG_DEBUG_VM=y

so *no*. VM_BUG_ON() is no less deadly than a regular BUG_ON(). It
just allows some people to build smaller kernels, but apparently
distro people would rather have debugging than save a few kB of RAM.

The VM debvugging code has VM_WARN_ON() and VM_WARN_ON_ONCE() for
people who want to get a "oops, my assumptions were wrong"

Killing machines because somebody made an assumption that was wrong is not ok.

Killing the machine is ok if we have a situation where there literally
is no other choice.

                  Linus

  reply	other threads:[~2016-10-04  4:12 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-04  4:00 BUG_ON() in workingset_node_shadows_dec() triggers Linus Torvalds
2016-10-04  4:07 ` Andrew Morton
2016-10-04  4:12   ` Linus Torvalds [this message]
2016-10-04  7:03     ` Raymond Jennings
2016-10-04 16:03       ` Linus Torvalds
2016-10-04  8:02 ` Greg KH
2016-10-04  9:32 ` Johannes Weiner
2016-10-05  1:21   ` Linus Torvalds
2016-10-05  9:25     ` Johannes Weiner
2016-10-05  9:31       ` Johannes Weiner
2016-10-05 10:40       ` Jan Kara
2016-10-05 16:10       ` Linus Torvalds
2016-10-05 17:00         ` [PATCH] checkpatch: extend BUG warning Joe Perches
2016-10-05 17:07           ` Linus Torvalds
2016-10-05  2:43 ` BUG_ON() in workingset_node_shadows_dec() triggers Paul Gortmaker
2016-10-05  3:29   ` Linus Torvalds
2016-10-05  5:44     ` Willy Tarreau
2016-10-05 15:52       ` Linus Torvalds
2016-10-05 19:06         ` Willy Tarreau
2016-10-05 19:18           ` Linus Torvalds
2016-10-05 21:09             ` Willy Tarreau
2016-10-05 21:14             ` Kees Cook
2016-10-05 21:46               ` Linus Torvalds
2016-10-05 22:17                 ` Kees Cook
2016-10-05 22:29                   ` Linus Torvalds
2016-10-06 22:07                     ` Kees Cook
2016-10-06 22:29                       ` Linus Torvalds
2016-10-06 23:05                         ` Kees Cook
2016-10-06 23:59                           ` Linus Torvalds
2016-10-07  5:48                             ` Willy Tarreau
2016-10-07 17:16                               ` Kees Cook
2016-10-07 17:21                                 ` Linus Torvalds
2016-10-07 17:33                                   ` Kees Cook
2016-10-07 18:26                                     ` Willy Tarreau
2016-10-06  1:59     ` Dave Chinner
2016-10-06  2:12       ` Linus Torvalds

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