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Date: Thu, 23 Jun 2016 20:54:27 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
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Subject: Re: [PATCH v3 00/13] Virtually mapped stacks with guard pages (x86,
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On Thu, Jun 23, 2016 at 11:00:08AM -0700, Kees Cook wrote:
> 
> Why does __mutex_lock_common() have "task" as a stack variable?

That's actually a fairly common thing to do. The reason is that
'current' is far more expensive to evaluate than a local variable.