Re: BUG_ON() in workingset_node_shadows_dec() triggers

From	Willy Tarreau <w@1wt.eu>
Newsgroups	linux.kernel
Subject	Re: BUG_ON() in workingset_node_shadows_dec() triggers
Date	2016-10-07 20:30 +0200
Message-ID	<spI49-4kf-1@gated-at.bofh.it> (permalink)
References	(5 earlier) <spqK2-85w-7@gated-at.bofh.it> <spwmm-416-3@gated-at.bofh.it> <spGYq-3AS-31@gated-at.bofh.it> <spH86-3EG-51@gated-at.bofh.it> <spHhL-3I7-11@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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

Thread

BUG_ON() in workingset_node_shadows_dec() triggers Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-04 06:10 +0200
  Re: BUG_ON() in workingset_node_shadows_dec() triggers Greg KH <greg@kroah.com> - 2016-10-04 10:20 +0200
  Re: BUG_ON() in workingset_node_shadows_dec() triggers Johannes Weiner <hannes@cmpxchg.org> - 2016-10-04 11:40 +0200
    Re: BUG_ON() in workingset_node_shadows_dec() triggers Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-05 03:30 +0200
      Re: BUG_ON() in workingset_node_shadows_dec() triggers Johannes Weiner <hannes@cmpxchg.org> - 2016-10-05 11:30 +0200
        Re: BUG_ON() in workingset_node_shadows_dec() triggers Johannes Weiner <hannes@cmpxchg.org> - 2016-10-05 11:40 +0200
        Re: BUG_ON() in workingset_node_shadows_dec() triggers Jan Kara <jack@suse.cz> - 2016-10-05 12:50 +0200
        Re: BUG_ON() in workingset_node_shadows_dec() triggers Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-05 18:20 +0200
          Re: [PATCH] checkpatch: extend BUG warning Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-05 19:10 +0200
          [PATCH] checkpatch: extend BUG warning Joe Perches <joe@perches.com> - 2016-10-05 19:10 +0200
  Re: BUG_ON() in workingset_node_shadows_dec() triggers Paul Gortmaker <paul.gortmaker@windriver.com> - 2016-10-05 04:50 +0200
    Re: BUG_ON() in workingset_node_shadows_dec() triggers Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-05 05:30 +0200
      Re: BUG_ON() in workingset_node_shadows_dec() triggers Willy Tarreau <w@1wt.eu> - 2016-10-05 07:50 +0200
        Re: BUG_ON() in workingset_node_shadows_dec() triggers Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-05 18:00 +0200
          Re: BUG_ON() in workingset_node_shadows_dec() triggers Willy Tarreau <w@1wt.eu> - 2016-10-05 21:10 +0200
            Re: BUG_ON() in workingset_node_shadows_dec() triggers Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-05 21:20 +0200
              Re: BUG_ON() in workingset_node_shadows_dec() triggers Willy Tarreau <w@1wt.eu> - 2016-10-05 23:20 +0200
              Re: BUG_ON() in workingset_node_shadows_dec() triggers Kees Cook <keescook@chromium.org> - 2016-10-05 23:20 +0200
                Re: BUG_ON() in workingset_node_shadows_dec() triggers Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-05 23:50 +0200
                Re: BUG_ON() in workingset_node_shadows_dec() triggers Kees Cook <keescook@chromium.org> - 2016-10-06 00:20 +0200
                Re: BUG_ON() in workingset_node_shadows_dec() triggers Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-06 00:40 +0200
                Re: BUG_ON() in workingset_node_shadows_dec() triggers Kees Cook <keescook@chromium.org> - 2016-10-07 00:10 +0200
                Re: BUG_ON() in workingset_node_shadows_dec() triggers Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-07 00:30 +0200
                Re: BUG_ON() in workingset_node_shadows_dec() triggers Kees Cook <keescook@chromium.org> - 2016-10-07 01:10 +0200
                Re: BUG_ON() in workingset_node_shadows_dec() triggers Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-07 02:00 +0200
                Re: BUG_ON() in workingset_node_shadows_dec() triggers Willy Tarreau <w@1wt.eu> - 2016-10-07 08:00 +0200
                Re: BUG_ON() in workingset_node_shadows_dec() triggers Kees Cook <keescook@chromium.org> - 2016-10-07 19:20 +0200
                Re: BUG_ON() in workingset_node_shadows_dec() triggers Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-07 19:30 +0200
                Re: BUG_ON() in workingset_node_shadows_dec() triggers Kees Cook <keescook@chromium.org> - 2016-10-07 19:40 +0200
                Re: BUG_ON() in workingset_node_shadows_dec() triggers Willy Tarreau <w@1wt.eu> - 2016-10-07 20:30 +0200
      Re: BUG_ON() in workingset_node_shadows_dec() triggers Dave Chinner <david@fromorbit.com> - 2016-10-06 04:10 +0200
        Re: BUG_ON() in workingset_node_shadows_dec() triggers Linus Torvalds <torvalds@linux-foundation.org> - 2016-10-06 04:20 +0200

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