From mboxrd@z Thu Jan  1 00:00:00 1970
From: hauke@hauke-m.de (Hauke Mehrtens)
Date: Tue, 30 Jul 2013 22:54:04 +0200
Subject: [PATCH v3 1/3] ARM: BCM5301X: initial support for the
 BCM5301X/BCM470X SoCs with ARM CPU
In-Reply-To: <20130730133601.GN11527@mudshark.cambridge.arm.com>
References: <1374792135-30343-1-git-send-email-hauke@hauke-m.de>
 <51F28A20.7060105@hauke-m.de>
 <20130726165311.GH17886@mudshark.cambridge.arm.com>
 <201307272149.17108.arnd@arndb.de>
 <20130730133601.GN11527@mudshark.cambridge.arm.com>
Message-ID: <51F827EC.3090104@hauke-m.de>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 07/30/2013 03:36 PM, Will Deacon wrote:
> On Sat, Jul 27, 2013 at 08:49:16PM +0100, Arnd Bergmann wrote:
>> On Friday 26 July 2013, Will Deacon wrote:
>>>>> At least, we need a pretty good explanation of what exactly is causing
>>>>> these spurious aborts before we start ignoring them unconditionally like
>>>>> this. You're effectively masking an extremely serious error indicator with
>>>>> this change.
>>>>
>>>> This fault occurs once every boot sometime early in the boot process,
>>>> but the actual time this happens varies randomly.
>>>
>>> Well that's interesting in itself. It sounds like we don't know *for sure*
>>> whether the abort is triggered by Linux. Since the abort is imprecise, the
>>> timing will vary.
>>
>> It might be possible to find out the culprit if you just enter an endless loop
>> in the early kernel boot code. If you enter the loop before Linux does something
>> wrong, it won't crash, otherwise it will. After that, you could bisect the
>> boot process by moving the busy loop around.
>>
>> If it even crashes at the point where Linux gets entered, it's a bug in the
>> boot loader.
> 
> Can you give Arnd's suggestion a go please Hauke?

Hi

I just tried that, but it did not crash in the loop. :-(

Now, with 3.11-rc3 it crashed reproducible after Freeing unused kernel
memory, see this:

[    0.859198] Freeing unused kernel memory: 1124K (c0260000 - c0379000)
[    0.866298] Unhandled fault: imprecise external abort (0x1c06) at
0xb6f8b005
[    0.873538] Kernel panic - not syncing: Attempted to kill init!
exitcode=0x00000007

Do you have some more informations about this type of error?

Hauke