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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 02D05C433EF for ; Sat, 7 May 2022 10:01:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 611966B008A; Sat, 7 May 2022 06:01:10 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5C1C76B008C; Sat, 7 May 2022 06:01:10 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4B1006B0092; Sat, 7 May 2022 06:01:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 39C2C6B008A for ; Sat, 7 May 2022 06:01:10 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 0C40860903 for ; Sat, 7 May 2022 10:01:10 +0000 (UTC) X-FDA: 79438503900.21.0E670F6 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) by imf10.hostedemail.com (Postfix) with ESMTP id 614E1C003B for ; Sat, 7 May 2022 10:00:50 +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-285-a07I9tQYN4-ed0PF2CZy2w-1; Sat, 07 May 2022 11:01:04 +0100 X-MC-Unique: a07I9tQYN4-ed0PF2CZy2w-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 15.0.1497.32; Sat, 7 May 2022 11:01:03 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.033; Sat, 7 May 2022 11:01:03 +0100 From: David Laight To: 'Jagdish Gediya' CC: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "gregkh@linuxfoundation.org" , "rafael@kernel.org" , "akpm@linux-foundation.org" , "keescook@chromium.org" , "andriy.shevchenko@linux.intel.com" , "geert@linux-m68k.org" , "linux@roeck-us.net" , "adobriyan@gmail.com" Subject: RE: [PATCH] kobject: Refactor kobject_set_name_vargs() Thread-Topic: [PATCH] kobject: Refactor kobject_set_name_vargs() Thread-Index: AQHYYU3qLELCyca9fE2SaEK1v39Vvq0R6/5wgAAc1ACAASXE8A== Date: Sat, 7 May 2022 10:01:03 +0000 Message-ID: <97b8979ff52c4404bf74eeda574d6b23@AcuMS.aculab.com> References: <20220506133309.36794-1-jvgediya@linux.ibm.com> <5902e26ef400451b966be2dd0fbd1575@AcuMS.aculab.com> 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 X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 614E1C003B Authentication-Results: imf10.hostedemail.com; dkim=none; spf=pass (imf10.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-Rspam-User: X-Stat-Signature: kt6ugyc6777xd97howa77dk7xs86ifyd X-HE-Tag: 1651917650-114381 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000006, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Jagdish Gediya > Sent: 06 May 2022 18:24 ... > > Are you sure this can ever work from a module? > > This all relies on: > > > > static inline bool is_kernel_rodata(unsigned long addr) > > { > > =09return addr >=3D (unsigned long)__start_rodata && > > =09 addr < (unsigned long)__end_rodata; > > } > > > > which isn't going to do anything sane given an "xxx" inside a module. > > > > Indeed can kobject_set_name_vargs() end up with a constant string > > inside a module? >=20 > No, kobject_set_name_vargs() is not exported. I exported > set_name_vargs() because it can have a broader use, but you are right > it shouldn't be exported. I was thinking that some function that creates a 'kobject' could easily be called from a module - so you end up calling the set_name code from a module and then end up calling kfree() on a literal from a module. Now it might be that it is impossible to actually the quoted literal from a module into somewhere that is_kernel_rodata() is applied to. But, as i said, it is fragile. =09David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1= PT, UK Registration No: 1397386 (Wales)