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Date:   Fri, 24 Jun 2022 12:42:23 +0100
From:   Mark Brown <broonie@kernel.org>
To:     Will Deacon <will@kernel.org>
Cc:     madvenka@linux.microsoft.com, mark.rutland@arm.com,
        jpoimboe@redhat.com, ardb@kernel.org, nobuta.keiya@fujitsu.com,
        sjitindarsingh@gmail.com, catalin.marinas@arm.com,
        jamorris@linux.microsoft.com, linux-arm-kernel@lists.infradead.org,
        live-patching@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v15 0/6] arm64: Reorganize the unwinder and implement
 stack trace reliability checks
Message-ID: <YrWjH4H7KxLAqfph@sirena.org.uk>
References: <ff68fb850d42e1adaa6a0a6c9c258acabb898b24>
 <20220617210717.27126-1-madvenka@linux.microsoft.com>
 <20220623173224.GB16966@willie-the-truck>
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On Thu, Jun 23, 2022 at 06:32:24PM +0100, Will Deacon wrote:
> On Fri, Jun 17, 2022 at 04:07:11PM -0500, madvenka@linux.microsoft.com wrote:

> > as HAVE_RELIABLE_STACKTRACE depends on STACK_VALIDATION which is not present
> > yet. This patch will be added in the future once Objtool is enhanced to
> > provide stack validation in some form.

> Given that it's not at all obvious that we're going to end up using objtool
> for arm64, does this patch series gain us anything in isolation?

Having the reliability information seems like it should be useful in
general even without doing live patching - we can use it to annotate
stack traces to warn people about anything that might be suspect in
there.  For live patching it's probably something we'll want regardless
of the use of objtool, it's one more robustness check which always
helps.

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