Date: Wed, 16 Oct 2013 15:57:30 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: paulmck@linux.vnet.ibm.com
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        "H. Peter Anvin" <hpa@linux.intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        "x86@kernel.org" <x86@kernel.org>,
        "Wang, Xiaoming" <xiaoming.wang@intel.com>,
        "Li, Zhuangzhi" <zhuangzhi.li@intel.com>,
        "Liu, Chuansheng" <chuansheng.liu@intel.com>
Subject: Re: [PATCH] x86: Remove WARN_ON(in_nmi()) from vmalloc_fault
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On Wed, 16 Oct 2013 12:36:32 -0700
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:


> > Ah but we have an in_interrupt() check in context_tracking_user_enter() that protects
> > us against that.
> 
> Here you are relying on the exception being treated as an interrupt,
> correct?

I don't think so. It's relying on nmi_enter() also makes in_interrupt()
return true.

Like I said before. An NMI interrupting userspace should be no
different than an interrupt interrupting userspace. They both can
trigger vmalloc faults, and we should be able to deal with it.

-- Steve
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