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[209.132.180.67]) by mx.google.com with ESMTP id s84-v6si16918197pfg.175.2018.06.18.23.17.38; Mon, 18 Jun 2018 23:17:51 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=mHmNs6t0; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965664AbeFSGPz (ORCPT + 99 others); Tue, 19 Jun 2018 02:15:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:36520 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965628AbeFSGPv (ORCPT ); Tue, 19 Jun 2018 02:15:51 -0400 Received: from localhost (unknown [5.29.173.205]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7D04A20661; Tue, 19 Jun 2018 06:15:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1529388951; bh=2rXwaeCoJtxv0wC5UH1amBJANT5ZUv5FmaKRz9zKIRc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mHmNs6t06ztD7Q/rTyZ9fLtsvTNOO8JOIQZN60pW2w5tavxp2fpCbYFHRiQmX9sbj w9Udr2DS8TU8I43HeySNVqOsLb36cnXdcpGj875W/yb1Io6r32d9fOLWhxD+ugYTYn Ayz1XM+CqBPJu3z/N8PJp4edPe5OY/a893MNFVq8= Date: Tue, 19 Jun 2018 09:15:48 +0300 From: Leon Romanovsky To: Christoph Hellwig Cc: Dan Williams , Jason Gunthorpe , john.hubbard@gmail.com, Matthew Wilcox , Michal Hocko , Christopher Lameter , Jan Kara , Linux MM , LKML , linux-rdma , John Hubbard Subject: Re: [PATCH 2/2] mm: set PG_dma_pinned on get_user_pages*() Message-ID: <20180619061548.GC7557@mtr-leonro.mtl.com> References: <20180617012510.20139-1-jhubbard@nvidia.com> <20180617012510.20139-3-jhubbard@nvidia.com> <20180617200432.krw36wrcwidb25cj@ziepe.ca> <20180618081113.GA16991@lst.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="7iMSBzlTiPOCCT2k" Content-Disposition: inline In-Reply-To: <20180618081113.GA16991@lst.de> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --7iMSBzlTiPOCCT2k Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Jun 18, 2018 at 10:11:13AM +0200, Christoph Hellwig wrote: > On Sun, Jun 17, 2018 at 01:10:04PM -0700, Dan Williams wrote: > > I believe kernel behavior regression is a primary concern as now > > fallocate() and truncate() can randomly fail where they didn't before. > > Fail or block forever due to actions of other unprivileged users. > > That is a complete no-go. They will fail "properly" with some error, which is better than current situation where those unprivileged users can trigger oops. 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