From nobody Sun Nov 24 21:28:50 2024 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 5ECD1154BFC; Fri, 1 Nov 2024 20:45:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730493929; cv=none; b=mZ5WD2Ger/n/29I/IfLUyJ2J4hCNJ4nBXn9f5AcB4HRg51WRqQIgyW4y0okrZyTCUCUIQ5FQLSvRVC3JfVqVCLXrJpQueblsu7M1BekHcZZrsXkjjMvATsYQ4fvvHxVbbNdTnV7qv+RJdxdARiyJUhaOKloqo63CTKhplx1hnkg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730493929; c=relaxed/simple; bh=diFOF7xkuvBii4nhu7rBCrs4zdrQcuFj04D5kOLrVtY=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=czHOYYpqar9oB+mzorgKe268EXw7/yG6iKoCqITz6k9siEj/POzWOV4pKQMVVJXEWJcuxDj4sdHkTcZe5epHI2kNKWLcjmriLJAHtEd/IRj1bH89M61lX7LMhY8KFJUNEzIQOyt9DvvxCW1FeOXqaA41eK3wSwiSvi/pCMVn/8Q= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VkAG1wxT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="VkAG1wxT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 60B17C4CECD; Fri, 1 Nov 2024 20:45:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730493928; bh=diFOF7xkuvBii4nhu7rBCrs4zdrQcuFj04D5kOLrVtY=; h=Date:From:To:Cc:Subject:From; b=VkAG1wxTxfr31YdbAJQqbs3kgVyHLSBRc2QWMW/ugRZLKRvfiG+9YrxUij7NM/hhx m42Sbzx5bKL1kVkbQPUt/P9ia8Exzr2E+crdmeSjyjSz7exizT4n6uoWyx2MeeeT2E XtxN9ZNJS8FvMXil3wSo03QwV5dfoXVgNLxyX6Fjh1ZjU+CoMgBkR17aCeVUt4VFlz p5sTW7k0vgMP5ngmWBtgxA9HxbvNgmoQWkLxEA4ZW/xn00ksYaKqwXDN9CQWBdDu/8 4QmqlZZYM2VjnkNrmEi7nSnAIKzpj7b980VkOvbp9a0UAqGxyffEpm6ByPOl8YuU/m M51GmCbuv+Txg== Date: Fri, 1 Nov 2024 14:45:23 -0600 From: "Gustavo A. R. Silva" To: Theodore Ts'o , Jan Kara Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org Subject: [PATCH v2][next] jbd2: Avoid dozens of -Wflex-array-member-not-at-end warnings Message-ID: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" -Wflex-array-member-not-at-end was introduced in GCC-14, and we are getting ready to enable it, globally. Use the `DEFINE_RAW_FLEX()` helper for an on-stack definition of a flexible structure (`struct shash_desc`) where the size of the flexible-array member (`__ctx`) is known at compile-time, and refactor the rest of the code, accordingly. So, with this, fix 77 of the following warnings: include/linux/jbd2.h:1800:35: warning: structure containing a flexible arra= y member is not at the end of another structure [-Wflex-array-member-not-at= -end] Signed-off-by: Gustavo A. R. Silva Reviewed-by: Jan Kara --- Changes in v2: - Use DIV_ROUND_UP() to compute the number of elements for the flex array. (Jan Kara) v1: - Link: https://lore.kernel.org/linux-hardening/ZxvyavDjXDaV9cNg@kspp/ include/linux/jbd2.h | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h index 8aef9bb6ad57..50f7ea8714bf 100644 --- a/include/linux/jbd2.h +++ b/include/linux/jbd2.h @@ -1796,22 +1796,21 @@ static inline unsigned long jbd2_log_space_left(jou= rnal_t *journal) static inline u32 jbd2_chksum(journal_t *journal, u32 crc, const void *address, unsigned int length) { - struct { - struct shash_desc shash; - char ctx[JBD_MAX_CHECKSUM_SIZE]; - } desc; + DEFINE_RAW_FLEX(struct shash_desc, desc, __ctx, + DIV_ROUND_UP(JBD_MAX_CHECKSUM_SIZE, + sizeof(*((struct shash_desc *)0)->__ctx))); int err; =20 BUG_ON(crypto_shash_descsize(journal->j_chksum_driver) > JBD_MAX_CHECKSUM_SIZE); =20 - desc.shash.tfm =3D journal->j_chksum_driver; - *(u32 *)desc.ctx =3D crc; + desc->tfm =3D journal->j_chksum_driver; + *(u32 *)desc->__ctx =3D crc; =20 - err =3D crypto_shash_update(&desc.shash, address, length); + err =3D crypto_shash_update(desc, address, length); BUG_ON(err); =20 - return *(u32 *)desc.ctx; + return *(u32 *)desc->__ctx; } =20 /* Return most recent uncommitted transaction */ --=20 2.43.0