linux-kernel - Re: [PATCH] ARM: BUG() dies silently

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Message-ID: <BANLkTimhk_G0fapzHAf0Gc-XhqT0qu+VbQ@mail.gmail.com>
Date:	Mon, 4 Apr 2011 21:29:45 -0500
From:	"Ramirez Luna, Omar" <omar.ramirez@...com>
To:	Simon Glass <sjg@...omium.org>, Stephen Boyd <sboyd@...eaurora.org>
Cc:	Russell King <linux@....linux.org.uk>,
	lk <linux-kernel@...r.kernel.org>,
	lak <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] ARM: BUG() dies silently

Hi Simon, Stephen,

On Sun, Apr 3, 2011 at 2:15 AM, Stephen Boyd <sboyd@...eaurora.org> wrote:
> (Please stop top posting)
>
> On 4/1/2011 3:29 PM, Simon Glass wrote:
>> Hi Stephen,
>>
>> Sorry for the confusion, but in fact I was talking about the patch to
>> make ARM use the generic bug handling via an undef instruction instead
>> of calling ______bug() or writing to memory address 0. Please see
>> here:
>>
>> http://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=6808/1
>
> Yes I've seen your patch (and even posted comments on it which have not
> been responded to).
>
> Correct me if I'm wrong, but that patch with CONFIG_BUG=n would lead to
> the same error that Omar is seeing because the code only modifies the
> bug infrastructure when CONFIG_BUG=y.

I am using CONFIG_BUG=y, however I don't have CONFIG_DEBUG_BUGVERBOSE
and hence I fall into the part which doesn't print the file and the
line where the BUG was found.

With Simon's patch if my .config had:

CONFIG_BUG=y
CONFIG_GENERIC_BUG is not set
CONFIG_DEBUG_BUGVERBOSE is not set

I would fall into the same BUG definition that is causing issues:

#define BUG()           do { *(int *)0 = 0; } while (1)

OTOH, is not like "Use generic BUG() handler" gives the choice of
removing GENERIC_BUG given that it is not prompted in menuconfig and
auto selected, if this is the intention is there any reason to keep
the #else part of /* not CONFIG_GENERIC_BUG */? there is no way we can
use it with this patch, right?

Regards,

Omar
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