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From: Peter Zijlstra <peterz@infradead.org>
Subject: Re: [RFC PATCH v6 1/5] Thread-local ABI system call: cache CPU
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Date: Thu, 7 Apr 2016 12:31:58 +0200
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On Thu, Apr 07, 2016 at 11:01:25AM +0200, Florian Weimer wrote:
> > Because ideally this structure would be part of the initial (glibc) TCB
> > with fixed offset etc.
> 
> This is not possible because we have layering violations and code
> assumes it knows the precise of the glibc TCB.  I think Address
> Sanitizer is in this category.  This means we cannot adjust the TCB size
> based on the kernel headers used to compile glibc, and there will have
> to be some indirection.

So with the proposed fixed sized object it would work, right?

Which is part of the reason its being proposed as a fixed sized object.