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From: Willy Tarreau <w@1wt.eu>
To: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Paul Gortmaker <paul.gortmaker@windriver.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Andrew Morton <akpm@linux-foundation.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: Fri, 7 Oct 2016 20:26:43 +0200	[thread overview]
Message-ID: <20161007182643.GA10538@1wt.eu> (raw)
In-Reply-To: <CAGXu5jKPA1-=LdnXZLxXpzUaFKKnMbfyNg89y_UryWd4V9hGnA@mail.gmail.com>

Hi Kees,

On Fri, Oct 07, 2016 at 10:33:33AM -0700, Kees Cook wrote:
> I'll quit debating how to change things, but I'll just try to point
> out that the "stop execution" logic, currently, is not an accident.
> Without CONFIG_BUG, BUG is defined as "do {} while (1)", and without
> CONFIG_HAVE_ARCH_BUG, BUG is defined as "printk(...); panic(...);".

I think we're all convinced about this *initial* intent. However among
the 3197 BUG() and 9594 BUG_ON() that are present in v4.8, how many
should *really* be of them ? I'm seeing that during 4.8 development
cycle alone, we managed to add 81 BUG() and 55 BUG_ON(). I doubt we
found so many valid reasons to kill the system. 38 of them were added
to drivers/. The problem is that this "style" has accumulated over the
years. We only had 1739 BUG() and 1801 BUG_ON() in 2.6.12. So we
roughly multiplied that by 4 in 11 years.

The current trend seems to actually be to remove some of them, 3 were
removed from lib/, 4 from include/, 29 removed from fs/, one removed
from mm/ but two added to kernel/ and 3 other ones to net/.

Maybe changing only kernel/ and mm/'s BUG() occurrences to something
like "I_KNOW_I_WILL_BE_BLAMED_FOR_THIS_BUG()" and letting them kill
until they're properly audited, and leaving the other ones non-fatal
could be a reasonable tradeoff to start with ?

Willy

  reply	other threads:[~2016-10-07 18:27 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
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 [this message]
2016-10-06  1:59     ` Dave Chinner
2016-10-06  2:12       ` Linus Torvalds

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