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=-1.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS autolearn=unavailable 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 DEDBDC10F14 for ; Thu, 18 Apr 2019 14:36:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A9E1121479 for ; Thu, 18 Apr 2019 14:36:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="ylFkenx2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389275AbfDROgE (ORCPT ); Thu, 18 Apr 2019 10:36:04 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:53168 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731317AbfDROgE (ORCPT ); Thu, 18 Apr 2019 10:36:04 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x3IEJJ4K081960; Thu, 18 Apr 2019 14:34:46 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=AL/6XEs1B3BsG/bXzvFYIzuqptan4i6pMcE1H0+0SkI=; b=ylFkenx2gLgBHYyGmWupVhKcQN67lFFgacw3sDWrvc2UyMrlPdQyvRWc1MWjFkNik5jm 71B1aOguPFfyKZwocNP/SMGZxoxt7Fxi3QtN/SgpOhysgr/4HrVfbPeGtFHnwA3yIxlG Hy1hSEdxdOjsGvN/N6787w1ybzWXCK8WaBatHX4fFVDIF903zPvWinjxuorByNB7ibEF PNJoPTEBbn4WH+etQKqD4MGBh97w5FikjrdsLQhlVIen2uh7aIMHYexHO8Nf1B3EvtnK Lyg6v4V14wXFCheokSGz5j4y4rdfNOYyvGEP+ZwCp4EZo65ljg2Txcaea91uWAoku77x ag== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2130.oracle.com with ESMTP id 2rvwk41a9g-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 18 Apr 2019 14:34:46 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x3IEYHYK012588; Thu, 18 Apr 2019 14:34:45 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3030.oracle.com with ESMTP id 2rwe7b0mb3-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 18 Apr 2019 14:34:45 +0000 Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x3IEYZET027844; Thu, 18 Apr 2019 14:34:35 GMT Received: from [192.168.1.16] (/24.9.64.241) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 18 Apr 2019 07:34:35 -0700 Subject: Re: [RFC PATCH v9 03/13] mm: Add support for eXclusive Page Frame Ownership (XPFO) To: Kees Cook , Andy Lutomirski Cc: Linus Torvalds , Thomas Gleixner , Nadav Amit , Ingo Molnar , Juerg Haefliger , Tycho Andersen , Julian Stecklina , Konrad Rzeszutek Wilk , Juerg Haefliger , deepa.srinivasan@oracle.com, chris hyser , Tyler Hicks , David Woodhouse , Andrew Cooper , Jon Masters , Boris Ostrovsky , iommu , X86 ML , "linux-alpha@vger.kernel.org" , "open list:DOCUMENTATION" , Linux List Kernel Mailing , Linux-MM , LSM List , Khalid Aziz , Andrew Morton , Peter Zijlstra , Dave Hansen , Borislav Petkov , "H. Peter Anvin" , Arjan van de Ven , Greg Kroah-Hartman References: <20190417161042.GA43453@gmail.com> <20190417170918.GA68678@gmail.com> <56A175F6-E5DA-4BBD-B244-53B786F27B7F@gmail.com> <20190417172632.GA95485@gmail.com> <063753CC-5D83-4789-B594-019048DE22D9@gmail.com> From: Khalid Aziz Organization: Oracle Corp Message-ID: <8f9d059d-e720-cd24-faa6-45493fc012e0@oracle.com> Date: Thu, 18 Apr 2019 08:34:32 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9231 signatures=668685 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=8.0.1-1810050000 definitions=main-1904180098 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9231 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904180098 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/17/19 11:41 PM, Kees Cook wrote: > On Wed, Apr 17, 2019 at 11:41 PM Andy Lutomirski wrot= e: >> I don't think this type of NX goof was ever the argument for XPFO. >> The main argument I've heard is that a malicious user program writes a= >> ROP payload into user memory (regular anonymous user memory) and then >> gets the kernel to erroneously set RSP (*not* RIP) to point there. >=20 > Well, more than just ROP. Any of the various attack primitives. The NX > stuff is about moving RIP: SMEP-bypassing. But there is still basic > SMAP-bypassing for putting a malicious structure in userspace and > having the kernel access it via the linear mapping, etc. >=20 >> I find this argument fairly weak for a couple reasons. First, if >> we're worried about this, let's do in-kernel CFI, not XPFO, to >=20 > CFI is getting much closer. Getting the kernel happy under Clang, LTO, > and CFI is under active development. (It's functional for arm64 > already, and pieces have been getting upstreamed.) >=20 CFI theoretically offers protection with fairly low overhead. I have not played much with CFI in clang. I agree with Linus that probability of bugs in XPFO implementation itself is a cause of concern. If CFI in Clang can provide us the same level of protection as XPFO does, I wouldn't want to push for an expensive change like XPFO. If Clang/CFI can't get us there for extended period of time, does it make sense to continue to poke at XPFO? Thanks, Khalid From mboxrd@z Thu Jan 1 00:00:00 1970 From: Khalid Aziz Subject: Re: [RFC PATCH v9 03/13] mm: Add support for eXclusive Page Frame Ownership (XPFO) Date: Thu, 18 Apr 2019 08:34:32 -0600 Message-ID: <8f9d059d-e720-cd24-faa6-45493fc012e0@oracle.com> References: <20190417161042.GA43453@gmail.com> <20190417170918.GA68678@gmail.com> <56A175F6-E5DA-4BBD-B244-53B786F27B7F@gmail.com> <20190417172632.GA95485@gmail.com> <063753CC-5D83-4789-B594-019048DE22D9@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Kees Cook , Andy Lutomirski Cc: Dave Hansen , "open list:DOCUMENTATION" , Linux-MM , deepa.srinivasan@oracle.com, "H. Peter Anvin" , Nadav Amit , Thomas Gleixner , Tycho Andersen , X86 ML , LSM List , Ingo Molnar , Julian Stecklina , Arjan van de Ven , Peter Zijlstra , Konrad Rzeszutek Wilk , Jon Masters , Borislav Petkov , Boris Ostrovsky , chris hyser , "linux-alpha@vger.kernel.org" , Khalid Aziz , Juerg Haefliger , Andrew Cooper List-Id: iommu@lists.linux-foundation.org On 4/17/19 11:41 PM, Kees Cook wrote: > On Wed, Apr 17, 2019 at 11:41 PM Andy Lutomirski wrote: >> I don't think this type of NX goof was ever the argument for XPFO. >> The main argument I've heard is that a malicious user program writes a >> ROP payload into user memory (regular anonymous user memory) and then >> gets the kernel to erroneously set RSP (*not* RIP) to point there. > > Well, more than just ROP. Any of the various attack primitives. The NX > stuff is about moving RIP: SMEP-bypassing. But there is still basic > SMAP-bypassing for putting a malicious structure in userspace and > having the kernel access it via the linear mapping, etc. > >> I find this argument fairly weak for a couple reasons. First, if >> we're worried about this, let's do in-kernel CFI, not XPFO, to > > CFI is getting much closer. Getting the kernel happy under Clang, LTO, > and CFI is under active development. (It's functional for arm64 > already, and pieces have been getting upstreamed.) > CFI theoretically offers protection with fairly low overhead. I have not played much with CFI in clang. I agree with Linus that probability of bugs in XPFO implementation itself is a cause of concern. If CFI in Clang can provide us the same level of protection as XPFO does, I wouldn't want to push for an expensive change like XPFO. If Clang/CFI can't get us there for extended period of time, does it make sense to continue to poke at XPFO? Thanks, Khalid 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=-0.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 946F4C10F0E for ; Thu, 18 Apr 2019 14:35:59 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5979721479 for ; Thu, 18 Apr 2019 14:35:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="ylFkenx2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5979721479 Authentication-Results: mail.kernel.org; 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Thu, 18 Apr 2019 14:34:45 +0000 Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x3IEYZET027844; Thu, 18 Apr 2019 14:34:35 GMT Received: from [192.168.1.16] (/24.9.64.241) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 18 Apr 2019 07:34:35 -0700 Subject: Re: [RFC PATCH v9 03/13] mm: Add support for eXclusive Page Frame Ownership (XPFO) To: Kees Cook , Andy Lutomirski References: <20190417161042.GA43453@gmail.com> <20190417170918.GA68678@gmail.com> <56A175F6-E5DA-4BBD-B244-53B786F27B7F@gmail.com> <20190417172632.GA95485@gmail.com> <063753CC-5D83-4789-B594-019048DE22D9@gmail.com> From: Khalid Aziz Organization: Oracle Corp Message-ID: <8f9d059d-e720-cd24-faa6-45493fc012e0@oracle.com> Date: Thu, 18 Apr 2019 08:34:32 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9231 signatures=668685 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=8.0.1-1810050000 definitions=main-1904180098 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9231 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904180098 Cc: Dave Hansen , "open list:DOCUMENTATION" , Linux-MM , deepa.srinivasan@oracle.com, "H. Peter Anvin" , Thomas Gleixner , Tycho Andersen , X86 ML , LSM List , Ingo Molnar , Julian Stecklina , Arjan van de Ven , Peter Zijlstra , Konrad Rzeszutek Wilk , Jon Masters , Borislav Petkov , Boris Ostrovsky , chris hyser , "linux-alpha@vger.kernel.org" , Khalid Aziz , Juerg Haefliger , Andrew Cooper , Linux List Kernel Mailing , Tyler Hicks , iommu , Juerg Haefliger , Greg Kroah-Hartman , Andrew Morton , Linus Torvalds , David Woodhouse X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org Message-ID: <20190418143432.uxZ01RqnBRs2E7APi0V-9OOG1w-qlZsYRHGNVX_Zj7A@z> On 4/17/19 11:41 PM, Kees Cook wrote: > On Wed, Apr 17, 2019 at 11:41 PM Andy Lutomirski wrote: >> I don't think this type of NX goof was ever the argument for XPFO. >> The main argument I've heard is that a malicious user program writes a >> ROP payload into user memory (regular anonymous user memory) and then >> gets the kernel to erroneously set RSP (*not* RIP) to point there. > > Well, more than just ROP. Any of the various attack primitives. The NX > stuff is about moving RIP: SMEP-bypassing. But there is still basic > SMAP-bypassing for putting a malicious structure in userspace and > having the kernel access it via the linear mapping, etc. > >> I find this argument fairly weak for a couple reasons. First, if >> we're worried about this, let's do in-kernel CFI, not XPFO, to > > CFI is getting much closer. Getting the kernel happy under Clang, LTO, > and CFI is under active development. (It's functional for arm64 > already, and pieces have been getting upstreamed.) > CFI theoretically offers protection with fairly low overhead. I have not played much with CFI in clang. I agree with Linus that probability of bugs in XPFO implementation itself is a cause of concern. If CFI in Clang can provide us the same level of protection as XPFO does, I wouldn't want to push for an expensive change like XPFO. If Clang/CFI can't get us there for extended period of time, does it make sense to continue to poke at XPFO? Thanks, Khalid _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu 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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, 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 61FA8C10F0E for ; Thu, 18 Apr 2019 14:35:53 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3426321479 for ; Thu, 18 Apr 2019 14:35:53 +0000 (UTC) Authentication-Results: mail.kernel.org; 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Thu, 18 Apr 2019 14:34:45 +0000 Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x3IEYZET027844; Thu, 18 Apr 2019 14:34:35 GMT Received: from [192.168.1.16] (/24.9.64.241) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 18 Apr 2019 07:34:35 -0700 Subject: Re: [RFC PATCH v9 03/13] mm: Add support for eXclusive Page Frame Ownership (XPFO) To: Kees Cook , Andy Lutomirski References: <20190417161042.GA43453@gmail.com> <20190417170918.GA68678@gmail.com> <56A175F6-E5DA-4BBD-B244-53B786F27B7F@gmail.com> <20190417172632.GA95485@gmail.com> <063753CC-5D83-4789-B594-019048DE22D9@gmail.com> From: Khalid Aziz Organization: Oracle Corp Message-ID: <8f9d059d-e720-cd24-faa6-45493fc012e0@oracle.com> Date: Thu, 18 Apr 2019 08:34:32 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9231 signatures=668685 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=8.0.1-1810050000 definitions=main-1904180098 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9231 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904180098 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190418_073538_725292_8C663DD0 X-CRM114-Status: GOOD ( 20.81 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Dave Hansen , "open list:DOCUMENTATION" , Linux-MM , deepa.srinivasan@oracle.com, "H. Peter Anvin" , Nadav Amit , Thomas Gleixner , Tycho Andersen , X86 ML , LSM List , Ingo Molnar , Julian Stecklina , Arjan van de Ven , Peter Zijlstra , Konrad Rzeszutek Wilk , Jon Masters , Borislav Petkov , Boris Ostrovsky , chris hyser , "linux-alpha@vger.kernel.org" , Khalid Aziz , Juerg Haefliger , Andrew Cooper , Linux List Kernel Mailing , Tyler Hicks , iommu , Juerg Haefliger , Greg Kroah-Hartman , Andrew Morton , Linus Torvalds , David Woodhouse Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 4/17/19 11:41 PM, Kees Cook wrote: > On Wed, Apr 17, 2019 at 11:41 PM Andy Lutomirski wrote: >> I don't think this type of NX goof was ever the argument for XPFO. >> The main argument I've heard is that a malicious user program writes a >> ROP payload into user memory (regular anonymous user memory) and then >> gets the kernel to erroneously set RSP (*not* RIP) to point there. > > Well, more than just ROP. Any of the various attack primitives. The NX > stuff is about moving RIP: SMEP-bypassing. But there is still basic > SMAP-bypassing for putting a malicious structure in userspace and > having the kernel access it via the linear mapping, etc. > >> I find this argument fairly weak for a couple reasons. First, if >> we're worried about this, let's do in-kernel CFI, not XPFO, to > > CFI is getting much closer. Getting the kernel happy under Clang, LTO, > and CFI is under active development. (It's functional for arm64 > already, and pieces have been getting upstreamed.) > CFI theoretically offers protection with fairly low overhead. I have not played much with CFI in clang. I agree with Linus that probability of bugs in XPFO implementation itself is a cause of concern. If CFI in Clang can provide us the same level of protection as XPFO does, I wouldn't want to push for an expensive change like XPFO. If Clang/CFI can't get us there for extended period of time, does it make sense to continue to poke at XPFO? Thanks, Khalid _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel