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Date: Mon, 5 Jan 2015 15:07:54 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Jiri Olsa <jolsa@redhat.com>, Ingo Molnar <mingo@redhat.com>,
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        David Ahern <dsahern@gmail.com>, Paul Mackerras <paulus@samba.org>,
        Yanmin Zhang <yanmin.zhang@intel.com>
Subject: Re: [PATCH 1/2] perf: Move task_pt_regs sampling into arch code
Message-ID: <20150105140754.GF29390@twins.programming.kicks-ass.net>
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On Sun, Jan 04, 2015 at 10:36:19AM -0800, Andy Lutomirski wrote:
> On x86_64, at least, task_pt_regs may be only partially initialized
> in many contexts, so x86_64 should not use it without extra care
> from interrupt context, let alone NMI context.
> 
> This will allow x86_64 to override the logic and will supply some
> scratch space to use to make a cleaner copy of user regs.

Just wondering how bad it would be to fill out the actual pt_regs that
was previously partially initialized?