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Date: Wed, 10 Mar 2010 10:06:58 -0500
Message-ID: <817ecb6f1003100706l88ceffp72fd8c72d34a9fd8@mail.gmail.com>
Subject: Re: [tip:x86/mm] x86, mm: NX protection for kernel data
From: Siarhei Liakh <sliakh.lkml@gmail.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>, mingo@redhat.com, jmorris@namei.org,
       linux-kernel@vger.kernel.org, arjan@linux.intel.com, tglx@linutronix.de,
       jiang@cs.ncsu.edu, linux-tip-commits@vger.kernel.org
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>> Any suggestions on how should I proceed forward in troubleshooting this issue?
>
> Can you reproduce it in KVM?

Yes, it crashes in KVM.

> If yes then that might give you a more debuggable state than a crashed native
> system.

Running kernel in KVM under kgdb with a watchpoint set for
($eip>=_etext)&&($eip<=_edata) still produces a dump but without ever
triggering the watchpoint.
I was hoping that some Kernel Locking Guru would say "take a look at
__xxx_yyy_zzz(), the things it does always looked suspicious to me."
:)

But joking aside, I would really appreciate ANY advice on debugging
this problem, as my best idea at this point is to pretty much
single-step through the whole thing... And since I am not familiar
with lock debugging at all, this will take a long time to figure out
on my own.

Thank you, guys.