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In-Reply-To: <YbjIbpFRqMac/X8s@kroah.com>
From:   Alexander Potapenko <glider@google.com>
Date:   Tue, 14 Dec 2021 18:00:41 +0100
Message-ID: <CAG_fn=XSMbgyJZnivZCh30M3JYQsJZZ0yL+5z074B_WrEBkRDQ@mail.gmail.com>
Subject: Re: [PATCH 41/43] security: kmsan: fix interoperability with auto-initialization
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andrey Konovalov <andreyknvl@google.com>,
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        Eric Dumazet <edumazet@google.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
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        Vasily Gorbik <gor@linux.ibm.com>,
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On Tue, Dec 14, 2021 at 5:38 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> > @@ -124,6 +125,7 @@ choice
> >       config INIT_STACK_ALL_ZERO
> >               bool "zero-init everything (strongest and safest)"
> >               depends on CC_HAS_AUTO_VAR_INIT_ZERO
> > +             depends on !KMSAN
>
> So this means KMSAN is a developer debugging feature only and should
> never be turned on on a real device/server that has users?

100% correct. KMSAN is way slower than KASAN, it also eats 2/3 of your
memory to store the metadata.
I thought it was sort of self-evident, but I can surely mention this
explicitly in the cover letter.