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Date: Tue, 1 Feb 2022 11:34:23 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Marco Elver <elver@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>, Kees Cook <keescook@chromium.org>,
	Ingo Molnar <mingo@kernel.org>,
	Elena Reshetova <elena.reshetova@intel.com>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Alexander Potapenko <glider@google.com>, llvm@lists.linux.dev,
	kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] stack: Introduce CONFIG_RANDOMIZE_KSTACK_OFFSET
Message-ID: <20220201103423.GT20638@worktop.programming.kicks-ass.net>
References: <20220131090521.1947110-1-elver@google.com>
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In-Reply-To: <20220131090521.1947110-1-elver@google.com>

On Mon, Jan 31, 2022 at 10:05:20AM +0100, Marco Elver wrote:
> The randomize_kstack_offset feature is unconditionally compiled in when
> the architecture supports it.
> 
> To add constraints on compiler versions, we require a dedicated Kconfig
> variable. Therefore, introduce RANDOMIZE_KSTACK_OFFSET.
> 
> Furthermore, this option is now also configurable by EXPERT kernels:
> while the feature is supposed to have zero performance overhead when
> disabled, due to its use of static branches, there are few cases where
> giving a distribution the option to disable the feature entirely makes
> sense. For example, in very resource constrained environments, which
> would never enable the feature to begin with, in which case the
> additional kernel code size increase would be redundant.
> 
> Signed-off-by: Marco Elver <elver@google.com>
> Reviewed-by: Nathan Chancellor <nathan@kernel.org>

For both patches:

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>