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Mon, 14 Feb 2022 17:10:13 +0000 (UTC) X-FDA: 79142023506.02.9E33FA9 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) by imf11.hostedemail.com (Postfix) with ESMTP id 2345C40013 for ; Mon, 14 Feb 2022 17:10:12 +0000 (UTC) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-59-4uBsnFPgM72Ml12czhVz_g-1; Mon, 14 Feb 2022 17:10:09 +0000 X-MC-Unique: 4uBsnFPgM72Ml12czhVz_g-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.28; Mon, 14 Feb 2022 17:10:06 +0000 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.028; Mon, 14 Feb 2022 17:10:06 +0000 From: David Laight To: 'Christoph Hellwig' , Arnd Bergmann CC: Linus Torvalds , Christoph Hellwig , "linux-arch@vger.kernel.org" , "linux-mm@kvack.org" , "linux-api@vger.kernel.org" , "arnd@arndb.de" , "linux-kernel@vger.kernel.org" , "mark.rutland@arm.com" , "dalias@libc.org" , "linux-ia64@vger.kernel.org" , "linux-sh@vger.kernel.org" , "peterz@infradead.org" , "jcmvbkbc@gmail.com" , "guoren@kernel.org" , "sparclinux@vger.kernel.org" , "linux-hexagon@vger.kernel.org" , "linux-riscv@lists.infradead.org" , "will@kernel.org" , "ardb@kernel.org" , "linux-s390@vger.kernel.org" , "bcain@codeaurora.org" , "deller@gmx.de" , "x86@kernel.org" , "linux@armlinux.org.uk" , "linux-csky@vger.kernel.org" , "mingo@redhat.com" , "geert@linux-m68k.org" , "linux-snps-arc@lists.infradead.org" , "linux-xtensa@linux-xtensa.org" , "hca@linux.ibm.com" , "linux-alpha@vger.kernel.org" , "linux-um@lists.infradead.org" , "linux-m68k@lists.linux-m68k.org" , "openrisc@lists.librecores.org" , "green.hu@gmail.com" , "shorne@gmail.com" , "linux-arm-kernel@lists.infradead.org" , "monstr@monstr.eu" , "tsbogend@alpha.franken.de" , "linux-parisc@vger.kernel.org" , "nickhu@andestech.com" , "linux-mips@vger.kernel.org" , "stable@vger.kernel.org" , "dinguyen@kernel.org" , "ebiederm@xmission.com" , "richard@nod.at" , "akpm@linux-foundation.org" , "linuxppc-dev@lists.ozlabs.org" , "davem@davemloft.net" Subject: RE: [PATCH 03/14] nds32: fix access_ok() checks in get/put_user Thread-Topic: [PATCH 03/14] nds32: fix access_ok() checks in get/put_user Thread-Index: AQHYIcSLBVNsuZIR/kWyaxa2mA9Gq6yTRsYw Date: Mon, 14 Feb 2022 17:10:05 +0000 Message-ID: <8a6e309687d647e3aef8a88bdb0922af@AcuMS.aculab.com> References: <20220214163452.1568807-1-arnd@kernel.org> <20220214163452.1568807-4-arnd@kernel.org> In-Reply-To: Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Authentication-Results: imf11.hostedemail.com; dkim=none; spf=pass (imf11.hostedemail.com: domain of david.laight@aculab.com designates 185.58.86.151 as permitted sender) smtp.mailfrom=david.laight@aculab.com; dmarc=pass (policy=none) header.from=aculab.com X-Rspamd-Server: rspam07 X-Rspam-User: X-Rspamd-Queue-Id: 2345C40013 X-Stat-Signature: kdwcet9kp8su6bx7zpjnicdfwcitrjyh X-HE-Tag: 1644858612-674727 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000343, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Christoph Hellwig > Sent: 14 February 2022 17:01 >=20 > On Mon, Feb 14, 2022 at 05:34:41PM +0100, Arnd Bergmann wrote: > > From: Arnd Bergmann > > > > The get_user()/put_user() functions are meant to check for > > access_ok(), while the __get_user()/__put_user() functions > > don't. > > > > This broke in 4.19 for nds32, when it gained an extraneous > > check in __get_user(), but lost the check it needs in > > __put_user(). >=20 > Can we follow the lead of MIPS (which this was originally copied > from I think) and kill the pointless __get/put_user_check wrapper > that just obsfucate the code? Is it possible to make all these architectures fall back to a common definition somewhere? Maybe they need to define ACCESS_OK_USER_LIMIT - which can be different from TASK_SIZE. There'll be a few special cases, but most architectures have kernel addresses above userspace ones. =09David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1= PT, UK Registration No: 1397386 (Wales)