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From: Yonghong Song <yhs@fb.com>
To: Andrii Nakryiko <andriin@fb.com>, <bpf@vger.kernel.org>,
	<netdev@vger.kernel.org>, <ast@fb.com>, <daniel@iogearbox.net>
Cc: <andrii.nakryiko@gmail.com>, <kernel-team@fb.com>
Subject: Re: [PATCH bpf-next 2/4] libbpf: fix libbpf build on compilers missing __builtin_mul_overflow
Date: Thu, 20 Aug 2020 07:21:12 -0700	[thread overview]
Message-ID: <e145cd71-8432-59d0-81a5-b253935385e1@fb.com> (raw)
In-Reply-To: <20200820061411.1755905-2-andriin@fb.com>



On 8/19/20 11:14 PM, Andrii Nakryiko wrote:
> GCC compilers older than version 5 don't support __builtin_mul_overflow yet.
> Given GCC 4.9 is the minimal supported compiler for building kernel and the
> fact that libbpf is a dependency of resolve_btfids, which is dependency of
> CONFIG_DEBUG_INFO_BTF=y, this needs to be handled. This patch fixes the issue
> by falling back to slower detection of integer overflow in such cases.
> 
> Fixes: 029258d7b228 ("libbpf: Remove any use of reallocarray() in libbpf")
> Signed-off-by: Andrii Nakryiko <andriin@fb.com>

Acked-by: Yonghong Song <yhs@fb.com>

  reply	other threads:[~2020-08-20 14:21 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-20  6:14 [PATCH bpf-next 1/4] libbpf: fix detection of BPF helper call instruction Andrii Nakryiko
2020-08-20  6:14 ` [PATCH bpf-next 2/4] libbpf: fix libbpf build on compilers missing __builtin_mul_overflow Andrii Nakryiko
2020-08-20 14:21   ` Yonghong Song [this message]
2020-08-20  6:14 ` [PATCH bpf-next 3/4] selftests/bpf: fix two minor compilation warnings reported by GCC 4.9 Andrii Nakryiko
2020-08-20 14:21   ` Yonghong Song
2020-08-20  6:14 ` [PATCH bpf-next 4/4] selftests/bpf: list newest Clang built-ins needed for some CO-RE selftests Andrii Nakryiko
2020-08-20 14:22   ` Yonghong Song
2020-08-20 14:17 ` [PATCH bpf-next 1/4] libbpf: fix detection of BPF helper call instruction Yonghong Song
2020-08-20 15:16 ` Daniel Borkmann

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