From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Arnd Bergmann Date: Thu, 23 May 2013 14:09:02 +0200 References: <519DCBEF.3090208@asianux.com> <201305231259.43750.arnd@arndb.de> <20130523112401.GO18614@n2100.arm.linux.org.uk> In-Reply-To: <20130523112401.GO18614@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201305231409.02359.arnd@arndb.de> Subject: Re: [PATCH] arch: configuration, deleting 'CONFIG_BUG' since always need it. To: Russell King - ARM Linux Cc: Geert Uytterhoeven , Chen Gang , =?iso-8859-1?q?H=E5vard_Skinnemoen?= , Hans-Christian Egtvedt , Mike Frysinger , Yoshinori Sato , Richard Kuo , "James E.J. Bottomley" , Helge Deller , Benjamin Herrenschmidt , "paulus@samba.org" , Martin Schwidefsky , Heiko Carstens , linux390@de.ibm.com, Paul Mundt , Jeff Dike , Richard Weinberger , Thomas Gleixner , "mingo@redhat.com" , "H. Peter Anvin" , the arch/x86 maintainers , "Eric W. Biederman" , Serge Hallyn , Paul McKenney , Frederic Weisbecker , David Miller , Andrew Morton , Akinobu Mita , Catalin Marinas , Michel Lespinasse , Will Deacon , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "uclinux-dist-devel@blackfin.uclinux.org" , linux-hexagon@vger.kernel.org, Parisc List , "linuxppc-dev@lists.ozlabs.org" , linux-s390@vger.kernel.org, Linux-sh list , uml-devel , uml-user , Linux-Arch List-ID: On Thursday 23 May 2013, Russell King - ARM Linux wrote: > This is the problem you guys are missing - unreachable() means "we lose > control of the CPU at this point". I'm absolutely aware of this. Again, the current behaviour of doing nothing at all isn't very different from undefined behavior when you get when you get to the end of a function returning a pointer without a "return" statement, or when you return from a function that has determined that it is not safe to continue. > If you have an embedded system and you've taken out all the printk() > stuff, you most certainly want the system to do something if you hit > an unexpected condition. I did not claim that it was a good idea to disable BUG(), all I said is that "random stuff may happen" is probably what Matt Mackall had in mind when he introduced the option. Arnd