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From: Chen Gang <gang.chen@asianux.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: "Russell King - ARM Linux" <linux@arm.linux.org.uk>,
	"Geert Uytterhoeven" <geert@linux-m68k.org>,
	"Håvard Skinnemoen" <hskinnemoen@gmail.com>,
	"Hans-Christian Egtvedt" <egtvedt@samfundet.no>,
	"Mike Frysinger" <vapier@gentoo.org>,
	"Yoshinori Sato" <ysato@users.sourceforge.jp>,
	"Richard Kuo" <rkuo@codeaurora.org>,
	"James E.J. Bottomley" <jejb@parisc-linux.org>,
	"Helge Deller" <deller@gmx.de>,
	"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
	"paulus@samba.org" <paulus@samba.org>,
	"Martin Schwidefsky" <schwidefsky@de.ibm.com>,
	"Heiko Carstens" <heiko.carstens@de.ibm.com>,
	linux390@de.ibm.com, "Paul Mundt" <lethal@linux-sh.org>,
	"Jeff Dike" <jdike@addtoit.com>,
	"Richard Weinberger" <richard@nod.at>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"mingo@redhat.com" <mingo@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	"Serge Hallyn" <serge.hallyn@canonical.com>,
	"Paul McKenney" <paulmck@linux.vnet.ibm.com>,
	"Frederic Weisbecker" <fweisbec@gmail.com>,
	"David Miller" <davem@davemloft.net>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Akinobu Mita" <akinobu.mita@gmail.com>,
	"Catalin Marinas" <Catalin.Marinas@arm.com>,
	"Michel Lespinasse" <walken@google.com>,
	"Will Deacon" <will.deacon@arm.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"uclinux-dist-devel@blackfin.uclinux.org"
	<uclinux-dist-devel@blackfin.uclinux.org>,
	linux-hexagon@vger.kernel.org,
	"Parisc List" <linux-parisc@vger.kernel.org>,
	"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	linux-s390@vger.kernel.org,
	"Linux-sh list" <linux-sh@vger.kernel.org>,
	uml-devel <user-mode-linux-devel@lists.sourceforge.net>,
	uml-user <user-mode-linux-user@lists.sourceforge.net>,
	Linux-Arch <linux-arch@vger.kernel.org>
Subject: Re: [PATCH] arch: configuration, deleting 'CONFIG_BUG' since always need it.
Date: Thu, 23 May 2013 19:19:30 +0800	[thread overview]
Message-ID: <519DFB42.7010509@asianux.com> (raw)
In-Reply-To: <201305231259.43750.arnd@arndb.de>

On 05/23/2013 06:59 PM, Arnd Bergmann wrote:
> You don't just want to avoid the code for printing the bug message and
> the invalid instruction, we also want the compiler to not emit the 
> function call or check the enum for unexpected values. The meaning of
> BUG() is really that person writing that statement was sure it cannot
> happen unless there is a bug in the kernel, which has likely already
> corrupted data. Printing a diagnostic at this point is nice if someone
> is there to look at it, but letting the kernel do further actions that
> may be undefined is not going to make things worse.

So I think neither unreachable() nor panic() are suitable for this
condition.

I guess 'CONFIG_BUG' is not belong to common features, now (and in the
future), so it is not suitable still exist in "asm-generic/bug.h", need
remove it firstly.

And then let the specific architectures to implement their own BUG(), if
they want some special features.

SO most of arches can skip this issue.


Thanks.
-- 
Chen Gang

Asianux Corporation


  reply	other threads:[~2013-05-23 11:19 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-05-23  7:57 [PATCH] arch: configuration, deleting 'CONFIG_BUG' since always need it Chen Gang
2013-05-23  8:40 ` Geert Uytterhoeven
2013-05-23  8:54   ` Arnd Bergmann
2013-05-23  9:05   ` Russell King - ARM Linux
2013-05-23  9:12     ` Geert Uytterhoeven
2013-05-23  9:39       ` Arnd Bergmann
2013-05-23 10:04         ` Russell King - ARM Linux
2013-05-23 10:41           ` Chen Gang
2013-05-23 10:59           ` Arnd Bergmann
2013-05-23 11:19             ` Chen Gang [this message]
2013-05-23 11:24             ` Russell King - ARM Linux
2013-05-23 12:09               ` Arnd Bergmann
2013-05-23 12:50                 ` Russell King - ARM Linux
2013-05-23 14:10                   ` Geert Uytterhoeven
2013-05-24  2:13                     ` Chen Gang
2013-05-24  4:17                       ` Chen Gang
2013-05-26  4:43                         ` [PATCH v2] arch: configuration issue, random return value when disable 'CONFIG_BUG' Chen Gang
2013-05-28  8:19           ` [PATCH] arch: configuration, deleting 'CONFIG_BUG' since always need it Ingo Molnar
2013-05-28 10:25             ` Chen Gang
2013-05-28 14:49             ` Arnd Bergmann
2013-05-28 14:55             ` H. Peter Anvin
2013-05-28 15:43               ` Arnd Bergmann
2013-05-28 16:06                 ` H. Peter Anvin
2013-05-28 17:20                   ` Arnd Bergmann
2013-05-23 10:09         ` Eric W. Biederman
2013-05-23 10:29           ` Russell King - ARM Linux
2013-05-23 10:05       ` Chen Gang
2013-05-24  5:59 ` Eric W. Biederman

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