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From:   Jarmo Tiitto <jarmo.tiitto@gmail.com>
To:     Nathan Chancellor <nathan@kernel.org>,
        Kees Cook <keescook@chromium.org>
Cc:     Jarmo Tiitto <jarmo.tiitto@gmail.com>,
        Sami Tolvanen <samitolvanen@google.com>,
        Bill Wendling <wcw@google.com>,
        Nick Desaulniers <ndesaulniers@google.com>,
        clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org,
        morbo@google.com
Subject: Re: [PATCH v2 1/1] pgo: Fix allocate_node() v2
Date:   Fri, 04 Jun 2021 12:40:27 +0300
Message-ID: <3979125.JPf0czqrma@hyperiorarchmachine>
In-Reply-To: <202106031436.132E0ED9A@keescook>
References: <20210603133853.5383-1-jarmo.tiitto@gmail.com> <d7e94352-0b24-1ab1-8b54-b6ffd4347963@kernel.org> <202106031436.132E0ED9A@keescook>
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Kees Cook wrote perjantaina 4. kes=C3=A4kuuta 2021 0.36.39 EEST:
> On Thu, Jun 03, 2021 at 02:14:24PM -0700, Nathan Chancellor wrote:
> > On 6/3/2021 6:38 AM, Jarmo Tiitto wrote:
> > > Based on Kees and others feedback here is v2 patch
> > > that clarifies why the current checks in allocate_node()
> > > are flawed. I did fair amount of KGDB time on it.
> > >=20
> > > When clang instrumentation eventually calls allocate_node()
> > > the struct llvm_prf_data *p argument tells us from what section
> > > we should reserve the vnode: It either points into vmlinux's
> > > core __llvm_prf_data section or some loaded module's
> > > __llvm_prf_data section.
> > >=20
> > > But since we don't have access to corresponding
> > > __llvm_prf_vnds section(s) for any module, the function
> > > should return just NULL and ignore any profiling attempts
> > > from modules for now.
> > >=20
> > > Signed-off-by: Jarmo Tiitto <jarmo.tiitto@gmail.com>
> >=20
> > I agree with Nick on the comments about the commit message. A few more =
small
> > nits below, not sure they necessitate a v3, up to you. Thank you for the
> > patch!
>=20
> It would make my life easier to get a v3. :) I agree with all of
> Nathan's suggestions. :)
>=20
> Thanks!
>=20
> -Kees
>=20
> --=20
> Kees Cook
>=20
Hello,

Ok, I'll make the requested changes, noted by Nathan and post v3 patch soon=
=2E :-)
Btw. These patches were  based on kees/for-next/clang/features branch.

Thanks for patience.
=2DJarmo