linux-kernel - Re: [PATCH 4/4] bug: mark disabled BUG() as unreachable() code

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 27 Apr 2012 23:14:52 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Konstantin Khlebnikov <khlebnikov@...nvz.org>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>
Subject: Re: [PATCH 4/4] bug: mark disabled BUG() as unreachable() code

On Sat, 28 Apr 2012 09:10:18 +0400 Konstantin Khlebnikov <khlebnikov@...nvz.org> wrote:

> Konstantin Khlebnikov wrote:
> > This patch suppress some compiler warnings (if CONFIG_BUG=n)
> > "warning: control reaches end of non-void function"
> 
> With this patch gcc throw out loop at the end of do_exit():
> 
> 	schedule();
> 	BUG();
> 	/* Avoid "noreturn function does return".  */
> 	for (;;)
> 		cpu_relax();	/* For when BUG is null */
> 
> Is this ok? Probably not, and we need here some BUG_NORETURN() which
> really never returns even if CONFIG_BUG=n.

Probably we should do away with CONFIG_BUG.

CONFIG_BUG=n causes various compile-time warnings to come out when the
execution proceeds into places where we didn't intend and these aren't
worth fixing.

More seriously, I rather doubt that anyone ever sets it to n.  And it
would be a pretty dumb thing to do - if your kernel has seriously
malfunctioned and it *knows* that it malfunctioned, it will just
blunder on anyway not telling anyone about it.

It doesn't seem worth any effort to support this thing.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/