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In-Reply-To: <7189da9a-f634-01ae-194d-a4d14a319a1c@intel.com>
From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Wed, 22 Feb 2023 08:28:58 -0800
Message-ID: <CAADnVQKX0ZD=8Xu4U2H_vbyuNoXJv0UZ1OffUtqw3vs0v95ELQ@mail.gmail.com>
Subject: Re: [PATCH] bpf: Fix undeclared function 'barrier_nospec' warning
To:     Dave Hansen <dave.hansen@intel.com>
Cc:     Geert Uytterhoeven <geert@linux-m68k.org>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        John Fastabend <john.fastabend@gmail.com>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
        KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        bpf <bpf@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        Huacai Chen <chenhuacai@loongson.cn>
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On Wed, Feb 22, 2023 at 7:33 AM Dave Hansen <dave.hansen@intel.com> wrote:
>
> On 2/22/23 07:03, Geert Uytterhoeven wrote:
> > On Wed, Feb 22, 2023 at 9:26 AM Viresh Kumar <viresh.kumar@linaro.org> =
wrote:
> >> Add the missing header for architectures that don't define
> >> the barrier_nospec() macro. The nospec.h header is added after the
> >> inclusion of barrier.h to avoid redefining the macro for architectures
> >> that already define barrier_nospec() in their respective barrier.h
> >> headers.
> >>
> >> Fixes: 74e19ef0ff80 ("uaccess: Add speculation barrier to copy_from_us=
er()")
> >> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> >> ---
> >> Linus's master branch fails currently to build for arm64 without this =
commit.
> > Not just arm64 =F0=9F=99=81
> > http://kisskb.ellerman.id.au/kisskb/head/5b7c4cabbb65f5c469464da6c5f614=
cbd7f730f2
>
> Thanks for the fix, and sorry for the breakage, folks!  Obviously:
>
> Tested-by: Dave Hansen <dave.hansen@linux.intel.com>
>
> Now time to go make sure I have bpf turned on in all my cross builds.

Not clear why the broken commit got applied bypassing bpf@vger and not
going through BPF CI. :(

Yesterday I applied pretty much the same fix from Huacai Chen.

https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git/commit/?id=3D34=
5d24a91c79f408e355c8b7e873ccde0f097eea

and BPF CI is now back to green.

Linus,
Since the blast radius is big, may be apply the fix directly ?