From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35916C43441 for ; Tue, 27 Nov 2018 20:58:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E5A632086B for ; Tue, 27 Nov 2018 20:58:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="2xrIOv/V" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E5A632086B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726820AbeK1H6C (ORCPT ); Wed, 28 Nov 2018 02:58:02 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:37854 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726286AbeK1H6B (ORCPT ); Wed, 28 Nov 2018 02:58:01 -0500 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id wARKrtoE101044; Tue, 27 Nov 2018 20:57:55 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=kJT+UpF+FOrIiZ4vdkX4Ount0F0EYMkIf3U5ugRw4G0=; b=2xrIOv/Vl9wA17+fROPRgHCXqAnoQi8/rA2qLZRIEGEBzaEXO535W/qJD09t1Lpm+U+f Ntb9Fn1lY3305Kdxb2kEWDTvo1eSAyWUwkcFZ//Aa152KaE38aIakm0KTdWkR+ukgzod 3O1RhKTajnAxfHtG6GMnlj4/RHRBcF+b8jN3FyO4W5sKnf2+SkLjcLIVeFqNBoZNVwDE 0ke2jvRXcuZk2SgDno+OvAbsDO1xIyBbV3seZiR1mmmTjBpLHM74Z3bipw5XQHHbL8/V HTxYqSHATHAo9MMRYU1VdKI9pH/hoFwGPaZKQXJ4t6HkEY5Ul41V5Z7TGxAMdPD7Ei4i AA== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by aserp2120.oracle.com with ESMTP id 2nxxkqegk9-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 27 Nov 2018 20:57:55 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id wARKvsst006476 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 27 Nov 2018 20:57:54 GMT Received: from abhmp0005.oracle.com (abhmp0005.oracle.com [141.146.116.11]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id wARKvrS6004013; Tue, 27 Nov 2018 20:57:54 GMT Received: from dhcp-burlington7-2nd-B-east-10-152-55-162.usdhcp.oraclecorp.com (/10.152.32.65) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 27 Nov 2018 12:57:53 -0800 Subject: Re: [Xen-devel] [PATCH] pvcalls-front: fixes incorrect error handling To: Stefano Stabellini , PanBian Cc: Juergen Gross , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org References: <1542852432-30019-1-git-send-email-bianpan2016@163.com> <1f765e81-ed89-d110-74b1-cc8029a4555f@oracle.com> <20181127005823.GB125510@bp> 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: <0af126ad-1a74-e4c7-d74f-658a46757b9d@oracle.com> Date: Tue, 27 Nov 2018 15:57:39 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9090 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=29 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1811270176 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/27/18 3:37 PM, Stefano Stabellini wrote: > On Tue, 27 Nov 2018, PanBian wrote: >> On Mon, Nov 26, 2018 at 03:31:39PM -0500, Boris Ostrovsky wrote: >>> On 11/21/18 9:07 PM, Pan Bian wrote: >>>> kfree() is incorrectly used to release the pages allocated by >>>> __get_free_page() and __get_free_pages(). Use the matching deallocators >>>> i.e., free_page() and free_pages(), respectively. >>>> >>>> Signed-off-by: Pan Bian >>>> --- >>>> drivers/xen/pvcalls-front.c | 4 ++-- >>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c >>>> index 2f11ca7..77224d8 100644 >>>> --- a/drivers/xen/pvcalls-front.c >>>> +++ b/drivers/xen/pvcalls-front.c >>>> @@ -385,8 +385,8 @@ static int create_active(struct sock_mapping *map, int *evtchn) >>>> out_error: >>>> if (*evtchn >= 0) >>>> xenbus_free_evtchn(pvcalls_front_dev, *evtchn); >>>> - kfree(map->active.data.in); >>>> - kfree(map->active.ring); >>>> + free_pages((unsigned long)map->active.data.in, PVCALLS_RING_ORDER); >>> Is map->active.data.in guaranteed to be NULL when entering this routine? >> I am not sure yet. Sorry for that. I observed the mismatches between >> __get_free_page and kfree, and submitted the patch. >> >> But I think your consideration is reasonable. A better solution is to >> directly free bytes, a local variable that holds __get_free_pages return >> value. If you agree, I will rewrite the patch. > Like Boris said, map->active.ring and map->active.data.in are not > guaranteed to be NULL or != NULL here. For instance,map->active.ring can > be != NULL and map->active.data.in can be NULL. However, free_pages and > free_page should be able to cope with it, the same way that kfree is > able to cope with it? If map->active.data.in can be non-NULL on entry to this routine then I think this has been a problem all along. Pan's suggestion to use bytes for freeing is going to solve this (assuming bytes will be initialized to NULL). -boris > >>> -boris >>> >>>> + free_page((unsigned long)map->active.ring); >>>> return ret; >>>> } >>>>