From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Palmer Dabbelt <palmerdabbelt@google.com>,
linux-kselftest@vger.kernel.org, netdev@vger.kernel.org,
bpf@vger.kernel.org
Cc: shuah@kernel.org, ast@kernel.org, daniel@iogearbox.net,
kafai@fb.com, songliubraving@fb.com, yhs@fb.com, andriin@fb.com,
john.fastabend@gmail.com,
Palmer Dabbelt <palmerdabbelt@google.com>,
linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com,
kernel-team@android.com,
Jesper Dangaard Brouer <brouer@redhat.com>
Subject: Re: [PATCH] selftests/bpf: Elide a check for LLVM versions that can't compile it
Date: Fri, 24 Jan 2020 21:27:11 +0100 [thread overview]
Message-ID: <87ftg4fvmo.fsf@toke.dk> (raw)
In-Reply-To: <20200124180839.185837-1-palmerdabbelt@google.com>
Palmer Dabbelt <palmerdabbelt@google.com> writes:
> The current stable LLVM BPF backend fails to compile the BPF selftests
> due to a compiler bug. The bug has been fixed in trunk, but that fix
> hasn't landed in the binary packages I'm using yet (Fedora arm64).
> Without this workaround the tests don't compile for me.
>
> This patch triggers a preprocessor warning on LLVM versions that
> definitely have the bug. The test may be conservative (ie, I'm not sure
> if 9.1 will have the fix), but it should at least make the current set
> of stable releases work together.
>
> See https://reviews.llvm.org/D69438 for more information on the fix. I
> obtained the workaround from
> https://lore.kernel.org/linux-kselftest/aed8eda7-df20-069b-ea14-f06628984566@gmail.com/T/
>
> Fixes: 20a9ad2e7136 ("selftests/bpf: add CO-RE relocs array tests")
> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Having to depend on the latest trunk llvm to compile the selftests is
definitely unfortunate. I believe there are some tests that won't work
at all without trunk llvm (the fentry/fexit stuff comes to mind;
although I'm not sure if they'll fail to compile, just fail to run?).
Could we extend this type of checking to any such case?
-Toke
next prev parent reply other threads:[~2020-01-24 20:27 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-24 18:08 [PATCH] selftests/bpf: Elide a check for LLVM versions that can't compile it Palmer Dabbelt
2020-01-24 20:27 ` Toke Høiland-Jørgensen [this message]
2020-01-27 11:09 ` Daniel Borkmann
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