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On Tue, Nov 24, 2009 at 10:34:08AM -0500, Masami Hiramatsu wrote:And this comment doesn't tell us much what this brings us. The changelog tells it stands to avoid a text_mutex deadlock. I'm not sure why we would deadlock without it.
As Mathieu and I discussed on LKML (http://lkml.org/lkml/2009/11/21/187) text_mutex will be locked on the way of cpu-hotplug. Since kprobes locks text_mutex too and stop_machine() refers online_cpus, it will cause a dead-lock. So, I decided to use get_online_cpus() to locking hotplug while optimizing/unoptimizng.
Ah ok :) Could you add a comment in the code that explains it?
-- Masami Hiramatsu
Software Engineer Hitachi Computer Products (America), Inc. Software Solutions Division
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