From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from omta34.uswest2.a.cloudfilter.net (omta34.uswest2.a.cloudfilter.net [35.89.44.33]) (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 5E46A5C96 for ; Wed, 3 Apr 2024 00:49:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=35.89.44.33 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712105386; cv=none; b=PItmB8lERzhjUKEtgJKRB5de2ZQHWvEj8jpDFB3ay3821NsGrBba7E/gdiDue0UIXzG5zyEYifgWwHoWEXbh0ePQzJ7ylfagscA66kx3TTHfUQhlKvQ4v95a/UavNnS2iI3OI2BLomf54r0AU3xxQcsbvBzsevGkkAhmnC15klY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712105386; c=relaxed/simple; bh=4dK7C/kJTg/Koy+Ep9OVvmuPGFqFUCucC4exXTmjsvg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=HdQ8cqQwJwtSHBDXk7vn8EcmQqc9wMwRjWbJvfZKoeSqRckUbg810Bs41fyOVAVcy236DDY3N7jTdbbK90fV0ssNBze2n63ufCnaChNpGqVgF3oUqOKaWmeP77B984YzYbJJ3l/jshNeXg9MvjYSdN40iPDP1zDM3Qzsf2+PyjA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=embeddedor.com; spf=pass smtp.mailfrom=embeddedor.com; dkim=pass (2048-bit key) header.d=embeddedor.com header.i=@embeddedor.com header.b=DcBqJ7oG; arc=none smtp.client-ip=35.89.44.33 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=embeddedor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=embeddedor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=embeddedor.com header.i=@embeddedor.com header.b="DcBqJ7oG" Received: from eig-obgw-6009a.ext.cloudfilter.net ([10.0.30.184]) by cmsmtp with ESMTPS id reqCrGB47HXmArooxrvcB1; Wed, 03 Apr 2024 00:49:43 +0000 Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with ESMTPS id roowroEklnNCOroowrw6Ep; Wed, 03 Apr 2024 00:49:43 +0000 X-Authority-Analysis: v=2.4 cv=DKCJ4TNb c=1 sm=1 tr=0 ts=660ca7a7 a=1YbLdUo/zbTtOZ3uB5T3HA==:117 a=g72bLlCj1y9NqcwAG1Fglw==:17 a=IkcTkHD0fZMA:10 a=raytVjVEu-sA:10 a=wYkD_t78qR0A:10 a=WFhDUUEJ9-S_0BG-ZiwA:9 a=QEXdDO2ut3YA:10 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=embeddedor.com; s=default; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=VqSzRgQgO9eTxbwoLbmir62oY7qQGk+N1QEYVP7K5rY=; b=DcBqJ7oGhUHVJmv1gPsIUQNAl7 TGhTZ2d1xTlXKI8l3Mm2gs3S/F5o+kIMdeV6abMB7a7Yx/uKDpG9HAPmPA3K9oN0m43/BxV7GidmZ Mw+F8REthGPeIG4NMLZfwyY7T9bJTCdh2uLGEB6aFqWtk3v7JwaKAhvMWu5g7X5tr8ND1zZ24N0bI qqxAN3Spy41t6YxDI8VpccTFlvYmBbao3C5+GRqB5d1hRdC+VKm6vjvWOQFna/i4qN62mXPSSlCbs Xp0tjswCddJsaWsbR1n2L733wO1wh/AuSHxuV5S1gmZgr6g0txUzbUj+E8lDLz/vjtbfOPowrOJeB FINiheUw==; Received: from [201.162.240.213] (port=29677 helo=[192.168.166.44]) by gator4166.hostgator.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.96.2) (envelope-from ) id 1rroov-00178Y-2X; Tue, 02 Apr 2024 19:49:42 -0500 Message-ID: Date: Tue, 2 Apr 2024 18:49:34 -0600 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH][next] nfp: Avoid -Wflex-array-member-not-at-end warnings To: Jakub Kicinski , "Gustavo A. R. Silva" Cc: Louis Peens , "David S. Miller" , Eric Dumazet , Paolo Abeni , oss-drivers@corigine.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org References: <20240401212424.34a9a9cd@kernel.org> Content-Language: en-US From: "Gustavo A. R. Silva" In-Reply-To: <20240401212424.34a9a9cd@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 201.162.240.213 X-Source-L: No X-Exim-ID: 1rroov-00178Y-2X X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: ([192.168.166.44]) [201.162.240.213]:29677 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 3 X-Org: HG=hgshared;ORG=hostgator; X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes X-CMAE-Envelope: MS4xfAvuBDFLQCKAxy0Bf/RR821z+xi1gZj+FT5nJd6pmA0EoriIUNuRIeWzJd8ThLbGXqOTngbIDyh6LCxkPi5Z38/sHDVsXYWvtkcQzzIZ85D2gTMi/mv9 ViW3FW+T1C+4P0l/i6JD3umMpMSnlQGbDDoNxNXV2AZN00kRl66SXEdjup/LCxj9o5bekt8MpuoDE9k4YW8JMZWh3aj78YlrMPg= On 01/04/24 22:24, Jakub Kicinski wrote: > On Thu, 28 Mar 2024 19:17:10 -0600 Gustavo A. R. Silva wrote: >> --- a/drivers/net/ethernet/netronome/nfp/nfp_net_debugdump.c >> +++ b/drivers/net/ethernet/netronome/nfp/nfp_net_debugdump.c >> @@ -34,8 +34,11 @@ enum nfp_dumpspec_type { >> >> /* generic type plus length */ >> struct nfp_dump_tl { >> - __be32 type; >> - __be32 length; /* chunk length to follow, aligned to 8 bytes */ >> + /* New members must be added within the struct_group() macro below. */ >> + struct_group_tagged(nfp_dump_tl_hdr, hdr, >> + __be32 type; >> + __be32 length; /* chunk length to follow, aligned to 8 bytes */ >> + ); >> char data[]; >> }; > > I counted 9 references to nfp_dump_tl->data. > Better to add: > > static void *nfp_dump_tl_data(struct nfp_dump_tl *spec) > { > return &spec[1]; > } Unfortunately, that's out-of-bounds for the compiler, and well, basically the reason why flex-array members were created in the first place. I was looking into implementing two separate structs: struct nfp_dump_tl_hdr { __be32 type; __be32 length; /* chunk length to follow, aligned to 8 bytes */ }; struct nfp_dump_tl { __be32 type; __be32 length; /* chunk length to follow, aligned to 8 bytes */ char data[]; }; and at least for structs nfp_dumpspec_csr, nfp_dumpspec_rtsym, nfp_dump_csr, and nfp_dump_rtsym it'd be a clean change (no need for container_of()), but not for structs nfp_dumpspec_csr and nfp_dumpspec_rtsym because of some casts from the flex struct: nfp_add_tlv_size(): case NFP_DUMPSPEC_TYPE_ME_CSR: spec_csr = (struct nfp_dumpspec_csr *)tl; if (!nfp_csr_spec_valid(spec_csr)) ... case NFP_DUMPSPEC_TYPE_INDIRECT_ME_CSR: spec_csr = (struct nfp_dumpspec_csr *)tl; if (!nfp_csr_spec_valid(spec_csr)) ... case NFP_DUMPSPEC_TYPE_RTSYM: spec_rtsym = (struct nfp_dumpspec_rtsym *)tl; err = nfp_dump_single_rtsym(pf, spec_rtsym, dump); nfp_calc_rtsym_dump_sz(): spec_rtsym = (struct nfp_dumpspec_rtsym *)spec; At least for those two structs, it's probably more straightforward to use struct_group_tagged() and container_of(). -- Gustavo