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x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfK2Sloi+g+37Poi6oFo1/yPVlhpaZL1vmAlAh6t11idAnl1Sz+G3aB1OYfexoYOuXdt0o7+PmAUEWCs/xSZMJIhhFpz50mKnvwI5MHhKIOCcW6HiVJQh sNrz/8FriBJt96C90WYrPb5PutNRG04iGfs3UFdbO/Bm36NhBqxB6FwzIDIhIBztPMBfcslFUk77yQRpAh98x2c7YBz5lUhABq7IwzqMj5tMK9AUdPNPmVXp X-CM-Analysis: v=2.3 cv=Tq3Iegfh c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=kj9zAlcOel0A:10 a=Kd1tUaAdevIA:10 a=ag1SF4gXAAAA:8 a=VwQbUJbxAAAA:8 a=GHf74y9ojWS1WvwfnDgA:9 a=CjuIK1q_8ugA:10 a=x8gzFH9gYPwA:10 a=Yupwre4RP9_Eg_Bd0iYG:22 a=AjGcO6oz07-iQ99wixmX:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751278AbeDFAFP (ORCPT ); Thu, 5 Apr 2018 20:05:15 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:44202 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751259AbeDFAFP (ORCPT ); Thu, 5 Apr 2018 20:05:15 -0400 Date: Fri, 6 Apr 2018 01:04:43 +0100 From: Al Viro To: Christoph Hellwig Cc: Lars-Peter Clausen , Kees Cook , Greg KH , Felipe Balbi , Linus Torvalds , Andrew Morton , LKML , linux-usb@vger.kernel.org Subject: Re: [GIT PULL] USB/PHY driver patches for 4.17-rc1 Message-ID: <20180406000442.GQ30522@ZenIV.linux.org.uk> References: <20180404103121.GA7420@kroah.com> <2d80686d-529d-0238-b91c-3fb88bcf37d5@metafoo.de> <20180405073111.GA15981@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180405073111.GA15981@infradead.org> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-usb-owner@vger.kernel.org X-Mailing-List: linux-usb@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Thu, Apr 05, 2018 at 12:31:11AM -0700, Christoph Hellwig wrote: > On Thu, Apr 05, 2018 at 09:19:28AM +0200, Lars-Peter Clausen wrote: > > On 04/05/2018 08:31 AM, Kees Cook wrote: > > > On Wed, Apr 4, 2018 at 3:31 AM, Greg KH wrote: > > >> Lars-Peter Clausen (2): > > >> usb: gadget: ffs: Execute copy_to_user() with USER_DS set > > > > > > https://git.kernel.org/linus/4058ebf33cb0be88ca516f968eda24ab7b6b93e4 > > > > > > Isn't there a better way to do this without the set_fs() usage? We've > > > been try to eliminate it in the kernel. I thought there was a safer > > > way to use iters now? > > > > The problem is use_mm(). It needs to be accompanied with set_fs(DS_USER) to > > work reliably. This has simply been missing for this particular instance of > > use_mm(). > > To me it seems like use_mm() should do set_fs(USER_DS) and unuse_mm() > should do set_fs(KERNEL_DS) to get drivers outo of this mess. I'll see > if I can come up with patches for the next merge window. Yes on the former, not quite on the latter (we need to go back to the state before use_mm()). Said that, drm users of use_mm() look rather fishy and might be worth a good look...