linux-kernel - Re: [PATCH] kernel/sched/core.c: need return NULL when BUG() is defined as empty.

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:	Wed, 22 May 2013 18:19:35 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Russell King - ARM Linux <linux@....linux.org.uk>
Cc:	Chen Gang <gang.chen@...anux.com>,
	"mingo@...hat.com" <mingo@...hat.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] kernel/sched/core.c: need return NULL when BUG() is
 defined as empty.

On Wed, May 22, 2013 at 02:33:17PM +0100, Russell King - ARM Linux wrote:
> On Wed, May 22, 2013 at 11:11:56AM +0200, Peter Zijlstra wrote:
> > On Mon, May 20, 2013 at 03:48:53PM +0800, Chen Gang wrote:
> > > 
> > > When neither CONFIG_BUG nor HAVE_ARCH_BUG is defined, need let function
> > > return failure value ('NULL') instead of random value.
> > 
> > What will such a kernel do? Happily continue running whenever we hit a
> > BUG? that seems like a particularly bad idea. Should we not have a stub
> > BUG() function like:
> > 
> > void BUG(void) __attribute__((noreturn))
> > {
> > 	local_irq_disable();
> > 	while (1) ;
> > }
> 
> Eww.  So you've a platform where you have things like panic_on_oops
> enabled, and you hit this bug... do we really want to just stop?
> Wouldn't replacing BUG() with panic("BUG"); be better ?
> 
> But, this begs the question - what is the point of being able to turn
> off BUG() ?  As BUG() on any sensible architecture is implemented by
> placing the minimum of code at the callsite (eg, one instruction if
> not using verbose) anything like the above is likely to be bigger.
> 
> So, I'd actually argue that rather than trying to "fix" this, get rid
> of CONFIG_BUG and make it always enabled everywhere - just like what
> has recently been done with hotplug.

Works for me. 
--
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/