Date: Tue, 16 Jun 2009 14:37:10 -0400 (EDT)
From: Steven Rostedt <rostedt@goodmis.org>
To: Jake Edge <jake@lwn.net>
cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>
Subject: Re: problem with function_graph self-test?
In-Reply-To: <20090616122603.6a628097@chukar>
Message-ID: <alpine.DEB.2.00.0906161436200.26673@gandalf.stny.rr.com>
References: <20090616122603.6a628097@chukar>
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On Tue, 16 Jun 2009, Jake Edge wrote:

> Hi Steve,
> 
> This has taken me a bit to track down ... I built a kernel from Linus's
> git tree (as of this morning: commit
> 03347e2592078a90df818670fddf97a33eec70fb) and when i boot it, it locks
> up hard giving me a cursor in the upper left (which seems to grow then
> shrink once, if that tells anyone anything) and no other output ... i
> started messing with kernel params (turning off quiet, rhgb, adding
> boot_delay and, eventually figuring out i needed lpj as well) to try
> and extract some info ... it seems to reliably fail in the
> function_graph tracer self-test with a variety of messages (I
> unfortunately don't have a serial console on the laptop that I am
> using) ... two of the messages that I got (possibly from different
> boots):
> 
> BUG: unable to handle kernel NULL pointer dereference at 00000048
> BUG: Function graph tracer hang!
> 
> I can try and get more information, but I wanted to check first if you
> already know about this ... somehow i'll either need to type faster :)
> or reliably slow it down and take pictures, which I can do if you'd
> like ...
> 
> obviously, for my purposes, i can turn off the selftests and/or the
> function_graph tracer ...

No I have not seen this before. Could you send me your config. And if you 
can take a digital picture of the dump (if one is available) that would 
also be helpful.

Thanks,

-- Steve

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