From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7357C1170E for ; Mon, 11 Sep 2023 13:56:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1635C433C8; Mon, 11 Sep 2023 13:56:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1694440616; bh=xfQ1I86H8ZyYHtCt5KBb7WWOWArNauwvbcPPq4axhQg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Mb3vvkMlHynTOLkHb+blyQN/ea171ODwWGO3lnynZFHPRBbtMK2ErbvlVgqESlWZ3 dXGTbCW6Nya6gZaoPctmIcofsLJcMl5Q+zlBQnKxSLaHlPNp3d6QJGSwvT940GmVvT GtpVkDYRJ+1y2IFzA+BGPI6KJWUZfnwmC28TByC4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Colm Harrington , Alan Maguire , Yipeng Zou , Yonghong Song , Alexei Starovoitov , Sasha Levin Subject: [PATCH 6.5 107/739] selftests/bpf: fix static assert compilation issue for test_cls_*.c Date: Mon, 11 Sep 2023 15:38:26 +0200 Message-ID: <20230911134654.087424214@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230911134650.921299741@linuxfoundation.org> References: <20230911134650.921299741@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alan Maguire [ Upstream commit 416c6d01244ecbf0abfdb898fd091b50ef951b48 ] commit bdeeed3498c7 ("libbpf: fix offsetof() and container_of() to work with CO-RE") ...was backported to stable trees such as 5.15. The problem is that with older LLVM/clang (14/15) - which is often used for older kernels - we see compilation failures in BPF selftests now: In file included from progs/test_cls_redirect_subprogs.c:2: progs/test_cls_redirect.c:90:2: error: static assertion expression is not an integral constant expression sizeof(flow_ports_t) != ^~~~~~~~~~~~~~~~~~~~~~~ progs/test_cls_redirect.c:91:3: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression offsetofend(struct bpf_sock_tuple, ipv4.dport) - ^ progs/test_cls_redirect.c:32:3: note: expanded from macro 'offsetofend' (offsetof(TYPE, MEMBER) + sizeof((((TYPE *)0)->MEMBER))) ^ tools/testing/selftests/bpf/tools/include/bpf/bpf_helpers.h:86:33: note: expanded from macro 'offsetof' ^ In file included from progs/test_cls_redirect_subprogs.c:2: progs/test_cls_redirect.c:95:2: error: static assertion expression is not an integral constant expression sizeof(flow_ports_t) != ^~~~~~~~~~~~~~~~~~~~~~~ progs/test_cls_redirect.c:96:3: note: cast that performs the conversions of a reinterpret_cast is not allowed in a constant expression offsetofend(struct bpf_sock_tuple, ipv6.dport) - ^ progs/test_cls_redirect.c:32:3: note: expanded from macro 'offsetofend' (offsetof(TYPE, MEMBER) + sizeof((((TYPE *)0)->MEMBER))) ^ tools/testing/selftests/bpf/tools/include/bpf/bpf_helpers.h:86:33: note: expanded from macro 'offsetof' ^ 2 errors generated. make: *** [Makefile:594: tools/testing/selftests/bpf/test_cls_redirect_subprogs.bpf.o] Error 1 The problem is the new offsetof() does not play nice with static asserts. Given that the context is a static assert (and CO-RE relocation is not needed at compile time), offsetof() usage can be replaced by restoring the original offsetof() definition as __builtin_offsetof(). Fixes: bdeeed3498c7 ("libbpf: fix offsetof() and container_of() to work with CO-RE") Reported-by: Colm Harrington Signed-off-by: Alan Maguire Tested-by: Yipeng Zou Acked-by: Yonghong Song Link: https://lore.kernel.org/r/20230802073906.3197480-1-alan.maguire@oracle.com Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- tools/testing/selftests/bpf/progs/test_cls_redirect.h | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/test_cls_redirect.h b/tools/testing/selftests/bpf/progs/test_cls_redirect.h index 76eab0aacba0c..233b089d1fbac 100644 --- a/tools/testing/selftests/bpf/progs/test_cls_redirect.h +++ b/tools/testing/selftests/bpf/progs/test_cls_redirect.h @@ -12,6 +12,15 @@ #include #include +/* offsetof() is used in static asserts, and the libbpf-redefined CO-RE + * friendly version breaks compilation for older clang versions <= 15 + * when invoked in a static assert. Restore original here. + */ +#ifdef offsetof +#undef offsetof +#define offsetof(type, member) __builtin_offsetof(type, member) +#endif + struct gre_base_hdr { uint16_t flags; uint16_t protocol; -- 2.40.1