Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E778C433EF for ; Fri, 14 Jan 2022 09:35:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239803AbiANJfM convert rfc822-to-8bit (ORCPT ); Fri, 14 Jan 2022 04:35:12 -0500 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.86.151]:53078 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230141AbiANJfL (ORCPT ); Fri, 14 Jan 2022 04:35:11 -0500 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-113-N-IQipKrO-i71OVc75YCcg-1; Fri, 14 Jan 2022 09:35:09 +0000 X-MC-Unique: N-IQipKrO-i71OVc75YCcg-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 15.0.1497.26; Fri, 14 Jan 2022 09:35:08 +0000 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.026; Fri, 14 Jan 2022 09:35:08 +0000 From: David Laight To: 'Steven Rostedt' , Sven Schnelle CC: LKML , Ingo Molnar , Andrew Morton , Pingfan Liu , Masami Hiramatsu , Tom Zanussi , "hca@linux.ibm.com" , "deller@gmx.de" Subject: RE: [PATCH v2] tracing: Add test for user space strings when filtering on string pointers Thread-Topic: [PATCH v2] tracing: Add test for user space strings when filtering on string pointers Thread-Index: AQHYBkLm7AQ+C6qOvkCW4jNyMLz0qKxce3DQgAAF6wCAAEoUEIAFASf/gAB6SdA= Date: Fri, 14 Jan 2022 09:35:08 +0000 Message-ID: <0a249160215a44ee8789f12727667a42@AcuMS.aculab.com> References: <20220110115532.536088fd@gandalf.local.home> <31c11a47a8bc4e34a1a64d54a54bb944@AcuMS.aculab.com> <20220110122436.5302128f@gandalf.local.home> <7a0fefb7ed3542b4a49dee1e78b1668b@AcuMS.aculab.com> <20220113125754.0cb5273f@gandalf.local.home> <20220113165115.0c844df9@gandalf.local.home> <20220113211501.473ab5ca@gandalf.local.home> In-Reply-To: <20220113211501.473ab5ca@gandalf.local.home> 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 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Rostedt > Sent: 14 January 2022 02:15 > > On Thu, 13 Jan 2022 16:51:15 -0500 > Steven Rostedt wrote: > > > We could add something later. As it is currently the merge window, and this > > is a real bug, I'm going to just leave it as is, and we can work to fix the > > other archs later. I need to get a pull request ready by tomorrow. > > Actually I got this working, and looks like a reasonable answer to the > problem. It basically requires that the user specify that the pointer > points into user space for the kernel to read it. Certainly look better. I'm not sure about the difference between the _inatomic() and _nocheck() user access functions though. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)