From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx48lu/Q+Il7Fy7Znw1jfVXjqvn6sn8OOECzE2JbNdgD4tvLUx8Dt3y2l+z/8HcumXEsAZ41r ARC-Seal: i=1; a=rsa-sha256; t=1523885167; cv=none; d=google.com; s=arc-20160816; b=pTQ0icpPZkE/m0tu8EitrXx+jjgmQPdQvuw33fROw0vTUii6L+/oR4kmXrite+ZYEr tjMSNf6e8cbJO0BXw2HMKgHXkdNxg7vvtenfrgpVs57tJn18/RL0LhFMNKwcrK2YPMsI 5E2TpuFgoJxx+IaL2PEfViEI6u6NrQAchY0xqxdJdFUbbBeX8eK8Db+GntieEFNj+IU4 nJDArx1n/eH7WsZlavBMd2ug5CNC/Wg4Qi1xjR+VFfdINGeYqi4VbC6seWhlypi3mGVi 1lolkM/zmR0xZxGbrTg04XoOOuRpg7icEsWgDKi6oAdDPwC8JWC+08GfLGq3cUHHIwCO DYqQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-language:content-transfer-encoding:in-reply-to:mime-version :user-agent:date:message-id:autocrypt:openpgp:from:references:cc:to :subject:dkim-signature:delivered-to:list-id:list-subscribe :list-unsubscribe:list-help:list-post:precedence:mailing-list :arc-authentication-results; bh=D4xYDyHisWjJDJDYkGRDqsHXt7ykldcgfyDlZ5iZswg=; b=oZ1MXRiX+lf4AJMOP0ZVWu7kDUPvqEvFyxD7aPq0eOsXqU/R3VnRBt7IA/SVsYwV8t ppdNj1DNLIHuz7sjXhtTI+HsiRRsQ6Znb84XJMU0B2MPlx8qWSl0/BBpNQ9/de73vAkY gvV2U9uKCulwxQ4W4sH7QBbHC/fmDTQXzieHVJ05PDXVE3xu5eC/1T+NEQSObCxZ/lSW +ysNyW6fRum6+FfabPC6BJi6dSb7YA8JbBuTKrqCPwEuIKBMa790b5oNYvuoGipKiDb8 mjkvUuMQ1JW/3nyA+NGRmCn0yTaruzuTfI1M3swZVv5/SEgU8ZkX8AhUv/E88fXqRK2/ CCwQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2017-10-26 header.b=eHWt+54g; spf=pass (google.com: domain of kernel-hardening-return-13010-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-13010-gregkh=linuxfoundation.org@lists.openwall.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2017-10-26 header.b=eHWt+54g; spf=pass (google.com: domain of kernel-hardening-return-13010-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-13010-gregkh=linuxfoundation.org@lists.openwall.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm List-Post: List-Help: List-Unsubscribe: List-Subscribe: Subject: Re: [PATCH] x86/xen: Remove use of VLAs To: Laura Abbott , Juergen Gross Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com References: <20180413221146.28476-1-labbott@redhat.com> From: Boris Ostrovsky Openpgp: preference=signencrypt Autocrypt: addr=boris.ostrovsky@oracle.com; prefer-encrypt=mutual; keydata= xsFNBFH8CgsBEAC0KiOi9siOvlXatK2xX99e/J3OvApoYWjieVQ9232Eb7GzCWrItCzP8FUV PQg8rMsSd0OzIvvjbEAvaWLlbs8wa3MtVLysHY/DfqRK9Zvr/RgrsYC6ukOB7igy2PGqZd+M MDnSmVzik0sPvB6xPV7QyFsykEgpnHbvdZAUy/vyys8xgT0PVYR5hyvhyf6VIfGuvqIsvJw5 C8+P71CHI+U/IhsKrLrsiYHpAhQkw+Zvyeml6XSi5w4LXDbF+3oholKYCkPwxmGdK8MUIdkM d7iYdKqiP4W6FKQou/lC3jvOceGupEoDV9botSWEIIlKdtm6C4GfL45RD8V4B9iy24JHPlom woVWc0xBZboQguhauQqrBFooHO3roEeM1pxXjLUbDtH4t3SAI3gt4dpSyT3EvzhyNQVVIxj2 FXnIChrYxR6S0ijSqUKO0cAduenhBrpYbz9qFcB/GyxD+ZWY7OgQKHUZMWapx5bHGQ8bUZz2 SfjZwK+GETGhfkvNMf6zXbZkDq4kKB/ywaKvVPodS1Poa44+B9sxbUp1jMfFtlOJ3AYB0WDS Op3d7F2ry20CIf1Ifh0nIxkQPkTX7aX5rI92oZeu5u038dHUu/dO2EcuCjl1eDMGm5PLHDSP 0QUw5xzk1Y8MG1JQ56PtqReO33inBXG63yTIikJmUXFTw6lLJwARAQABzTNCb3JpcyBPc3Ry b3Zza3kgKFdvcmspIDxib3Jpcy5vc3Ryb3Zza3lAb3JhY2xlLmNvbT7CwXgEEwECACIFAlH8 CgsCGwMGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEIredpCGysGyasEP/j5xApopUf4g 9Fl3UxZuBx+oduuw3JHqgbGZ2siA3EA4bKwtKq8eT7ekpApn4c0HA8TWTDtgZtLSV5IdH+9z JimBDrhLkDI3Zsx2CafL4pMJvpUavhc5mEU8myp4dWCuIylHiWG65agvUeFZYK4P33fGqoaS VGx3tsQIAr7MsQxilMfRiTEoYH0WWthhE0YVQzV6kx4wj4yLGYPPBtFqnrapKKC8yFTpgjaK jImqWhU9CSUAXdNEs/oKVR1XlkDpMCFDl88vKAuJwugnixjbPFTVPyoC7+4Bm/FnL3iwlJVE qIGQRspt09r+datFzPqSbp5Fo/9m4JSvgtPp2X2+gIGgLPWp2ft1NXHHVWP19sPgEsEJXSr9 tskM8ScxEkqAUuDs6+x/ISX8wa5Pvmo65drN+JWA8EqKOHQG6LUsUdJolFM2i4Z0k40BnFU/ kjTARjrXW94LwokVy4x+ZYgImrnKWeKac6fMfMwH2aKpCQLlVxdO4qvJkv92SzZz4538az1T m+3ekJAimou89cXwXHCFb5WqJcyjDfdQF857vTn1z4qu7udYCuuV/4xDEhslUq1+GcNDjAhB nNYPzD+SvhWEsrjuXv+fDONdJtmLUpKs4Jtak3smGGhZsqpcNv8nQzUGDQZjuCSmDqW8vn2o hWwveNeRTkxh+2x1Qb3GT46uzsFNBFH8CgsBEADGC/yx5ctcLQlB9hbq7KNqCDyZNoYu1HAB Hal3MuxPfoGKObEktawQPQaSTB5vNlDxKihezLnlT/PKjcXC2R1OjSDinlu5XNGc6mnky03q yymUPyiMtWhBBftezTRxWRslPaFWlg/h/Y1iDuOcklhpr7K1h1jRPCrf1yIoxbIpDbffnuyz kuto4AahRvBU4Js4sU7f/btU+h+e0AcLVzIhTVPIz7PM+Gk2LNzZ3/on4dnEc/qd+ZZFlOQ4 KDN/hPqlwA/YJsKzAPX51L6Vv344pqTm6Z0f9M7YALB/11FO2nBB7zw7HAUYqJeHutCwxm7i BDNt0g9fhviNcJzagqJ1R7aPjtjBoYvKkbwNu5sWDpQ4idnsnck4YT6ctzN4I+6lfkU8zMzC gM2R4qqUXmxFIS4Bee+gnJi0Pc3KcBYBZsDK44FtM//5Cp9DrxRQOh19kNHBlxkmEb8kL/pw XIDcEq8MXzPBbxwHKJ3QRWRe5jPNpf8HCjnZz0XyJV0/4M1JvOua7IZftOttQ6KnM4m6WNIZ 2ydg7dBhDa6iv1oKdL7wdp/rCulVWn8R7+3cRK95SnWiJ0qKDlMbIN8oGMhHdin8cSRYdmHK kTnvSGJNlkis5a+048o0C6jI3LozQYD/W9wq7MvgChgVQw1iEOB4u/3FXDEGulRVko6xCBU4 SQARAQABwsFfBBgBAgAJBQJR/AoLAhsMAAoJEIredpCGysGyfvMQAIywR6jTqix6/fL0Ip8G jpt3uk//QNxGJE3ZkUNLX6N786vnEJvc1beCu6EwqD1ezG9fJKMl7F3SEgpYaiKEcHfoKGdh 30B3Hsq44vOoxR6zxw2B/giADjhmWTP5tWQ9548N4VhIZMYQMQCkdqaueSL+8asp8tBNP+TJ PAIIANYvJaD8xA7sYUXGTzOXDh2THWSvmEWWmzok8er/u6ZKdS1YmZkUy8cfzrll/9hiGCTj u3qcaOM6i/m4hqtvsI1cOORMVwjJF4+IkC5ZBoeRs/xW5zIBdSUoC8L+OCyj5JETWTt40+lu qoqAF/AEGsNZTrwHJYu9rbHH260C0KYCNqmxDdcROUqIzJdzDKOrDmebkEVnxVeLJBIhYZUd t3Iq9hdjpU50TA6sQ3mZxzBdfRgg+vaj2DsJqI5Xla9QGKD+xNT6v14cZuIMZzO7w0DoojM4 ByrabFsOQxGvE0w9Dch2BDSI2Xyk1zjPKxG1VNBQVx3flH37QDWpL2zlJikW29Ws86PHdthh Fm5PY8YtX576DchSP6qJC57/eAAe/9ztZdVAdesQwGb9hZHJc75B+VNm4xrh/PJO6c1THqdQ 19WVJ+7rDx3PhVncGlbAOiiiE3NOFPJ1OQYxPKtpBUukAlOTnkKE6QcA4zckFepUkfmBV1wM Jg6OxFYd01z+a+oL Message-ID: <7cf66c00-74c2-62bb-81f5-4332313a5a6e@oracle.com> Date: Mon, 16 Apr 2018 09:27:24 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180413221146.28476-1-labbott@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8864 signatures=668698 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1711220000 definitions=main-1804160127 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597670729617678421?= X-GMAIL-MSGID: =?utf-8?q?1597909413809504571?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 04/13/2018 06:11 PM, Laura Abbott wrote: > There's an ongoing effort to remove VLAs[1] from the kernel to eventually > turn on -Wvla. The few VLAs in use have an upper bound based on a size > of 64K. This doesn't produce an excessively large stack so just switch > the upper bound. > > [1] https://lkml.org/lkml/2018/3/7/621 > > Signed-off-by: Laura Abbott > --- > arch/x86/xen/enlighten_pv.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c > index c36d23aa6c35..d96a5a535cbb 100644 > --- a/arch/x86/xen/enlighten_pv.c > +++ b/arch/x86/xen/enlighten_pv.c > @@ -421,8 +421,7 @@ static void xen_load_gdt(const struct desc_ptr *dtr) > { > unsigned long va = dtr->address; > unsigned int size = dtr->size + 1; > - unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE); Isn't dtr->size always either GDT_SIZE or 0? -boris > - unsigned long frames[pages]; > + unsigned long frames[DIV_ROUND_UP(SZ_64K, PAGE_SIZE)]; > int f; > > /* > @@ -470,8 +469,7 @@ static void __init xen_load_gdt_boot(const struct desc_ptr *dtr) > { > unsigned long va = dtr->address; > unsigned int size = dtr->size + 1; > - unsigned pages = DIV_ROUND_UP(size, PAGE_SIZE); > - unsigned long frames[pages]; > + unsigned long frames[DIV_ROUND_UP(SZ_64K, PAGE_SIZE)]; > int f; > > /*