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 C1693FBF6 for ; Mon, 15 May 2023 17:43:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 24A88C433D2; Mon, 15 May 2023 17:43:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684172638; bh=gbsgF0jUZQHzoprFJRgaCygFbigEFv3rZN2HwzN1HcM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aSKoadXk9iG0O5Kc8koJ72luuPSszv0FRPot96a9Lg9om5DA4p6FY3LbtroeqjHJV D+ZnvyJ3AmAyw9JlHMuok6MNbTiVTViD066RCs/YAc8Qo1ukyjtE/KcEqT8JYT/ua2 hx3ktKHtQfU4394dv7YpDHwEpucASsfm9aNuxM3o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kevin Brodsky , Ruben Ayrapetyan , Petr Vorel , Masahiro Yamada , Sam Ravnborg , Andrew Morton , Sasha Levin Subject: [PATCH 5.10 218/381] uapi/linux/const.h: prefer ISO-friendly __typeof__ Date: Mon, 15 May 2023 18:27:49 +0200 Message-Id: <20230515161746.599059807@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230515161736.775969473@linuxfoundation.org> References: <20230515161736.775969473@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Kevin Brodsky [ Upstream commit 31088f6f7906253ef4577f6a9b84e2d42447dba0 ] typeof is (still) a GNU extension, which means that it cannot be used when building ISO C (e.g. -std=c99). It should therefore be avoided in uapi headers in favour of the ISO-friendly __typeof__. Unfortunately this issue could not be detected by CONFIG_UAPI_HEADER_TEST=y as the __ALIGN_KERNEL() macro is not expanded in any uapi header. This matters from a userspace perspective, not a kernel one. uapi headers and their contents are expected to be usable in a variety of situations, and in particular when building ISO C applications (with -std=c99 or similar). This particular problem can be reproduced by trying to use the __ALIGN_KERNEL macro directly in application code, say: #include int align(int x, int a) { return __KERNEL_ALIGN(x, a); } and trying to build that with -std=c99. Link: https://lkml.kernel.org/r/20230411092747.3759032-1-kevin.brodsky@arm.com Fixes: a79ff731a1b2 ("netfilter: xtables: make XT_ALIGN() usable in exported headers by exporting __ALIGN_KERNEL()") Signed-off-by: Kevin Brodsky Reported-by: Ruben Ayrapetyan Tested-by: Ruben Ayrapetyan Reviewed-by: Petr Vorel Tested-by: Petr Vorel Reviewed-by: Masahiro Yamada Cc: Sam Ravnborg Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- include/uapi/linux/const.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/uapi/linux/const.h b/include/uapi/linux/const.h index af2a44c08683d..a429381e7ca50 100644 --- a/include/uapi/linux/const.h +++ b/include/uapi/linux/const.h @@ -28,7 +28,7 @@ #define _BITUL(x) (_UL(1) << (x)) #define _BITULL(x) (_ULL(1) << (x)) -#define __ALIGN_KERNEL(x, a) __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1) +#define __ALIGN_KERNEL(x, a) __ALIGN_KERNEL_MASK(x, (__typeof__(x))(a) - 1) #define __ALIGN_KERNEL_MASK(x, mask) (((x) + (mask)) & ~(mask)) #define __KERNEL_DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d)) -- 2.39.2