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 X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A48CCC61DD8 for ; Sun, 15 Nov 2020 08:53:27 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2A7142419B for ; Sun, 15 Nov 2020 08:53:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="lX2fpz59" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2A7142419B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5A9B46B005C; Sun, 15 Nov 2020 03:53:26 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 532CD6B005D; Sun, 15 Nov 2020 03:53:26 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3D2436B0068; Sun, 15 Nov 2020 03:53:26 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0214.hostedemail.com [216.40.44.214]) by kanga.kvack.org (Postfix) with ESMTP id 0ADB36B005C for ; Sun, 15 Nov 2020 03:53:25 -0500 (EST) Received: from smtpin16.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id A2BE01EE6 for ; Sun, 15 Nov 2020 08:53:25 +0000 (UTC) X-FDA: 77486038770.16.copy65_530fccb2731f Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin16.hostedemail.com (Postfix) with ESMTP id 80262100E6917 for ; Sun, 15 Nov 2020 08:53:25 +0000 (UTC) X-HE-Tag: copy65_530fccb2731f X-Filterd-Recvd-Size: 5078 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf15.hostedemail.com (Postfix) with ESMTP for ; Sun, 15 Nov 2020 08:53:24 +0000 (UTC) Received: from kernel.org (unknown [77.125.7.142]) (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 3E7962242E; Sun, 15 Nov 2020 08:53:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605430403; bh=zogKbmLR5WuYYhS1A9PyjE2BBFUNYgIBXxOPOFu4jUs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lX2fpz594y7d/5i/mEef+AbbnIJzikgvOzNnoqSfFlQrJb9q90Elp66aOiMYcs1zs TTHjnJQu5Da13GIKSCOa/J3DAETZs6oYZ3AL3AqwfPmxmxZFENcF3lAkHuh559m70/ 7Mni0kOKQphJSxWriCKyHTtX74+IDbuZ2lYSWHfw= Date: Sun, 15 Nov 2020 10:53:07 +0200 From: Mike Rapoport To: Matthew Wilcox Cc: Andrew Morton , Alexander Viro , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Christopher Lameter , Dan Williams , Dave Hansen , David Hildenbrand , Elena Reshetova , "H. Peter Anvin" , Ingo Molnar , James Bottomley , "Kirill A. Shutemov" , Mark Rutland , Mike Rapoport , Michael Kerrisk , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , Rick Edgecombe , Shuah Khan , Thomas Gleixner , Tycho Andersen , Will Deacon , linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-nvdimm@lists.01.org, linux-riscv@lists.infradead.org, x86@kernel.org, Hagen Paul Pfeifer Subject: Re: [PATCH v8 4/9] mm: introduce memfd_secret system call to create "secret" memory areas Message-ID: <20201115085307.GV4758@kernel.org> References: <20201110151444.20662-1-rppt@kernel.org> <20201110151444.20662-5-rppt@kernel.org> <20201113135848.GF17076@casper.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201113135848.GF17076@casper.infradead.org> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Nov 13, 2020 at 01:58:48PM +0000, Matthew Wilcox wrote: > On Tue, Nov 10, 2020 at 05:14:39PM +0200, Mike Rapoport wrote: > > +static vm_fault_t secretmem_fault(struct vm_fault *vmf) > > +{ > > + struct address_space *mapping = vmf->vma->vm_file->f_mapping; > > + struct inode *inode = file_inode(vmf->vma->vm_file); > > + pgoff_t offset = vmf->pgoff; > > + unsigned long addr; > > + struct page *page; > > + int ret = 0; > > + > > + if (((loff_t)vmf->pgoff << PAGE_SHIFT) >= i_size_read(inode)) > > + return vmf_error(-EINVAL); > > + > > + page = find_get_entry(mapping, offset); > > Why did you decide to use find_get_entry() here? You don't handle > swap or shadow entries. Right, I've missed that. > > + if (!page) { > > + page = secretmem_alloc_page(vmf->gfp_mask); > > + if (!page) > > + return vmf_error(-EINVAL); > > Why is this EINVAL and not ENOMEM? Ah, I was annoyed by OOMs I got when I simulated various allocation failures, so I changed it to get SIGBUS instead and than forgot to restore. Will fix. > > + ret = add_to_page_cache(page, mapping, offset, vmf->gfp_mask); > > + if (unlikely(ret)) > > + goto err_put_page; > > + > > + ret = set_direct_map_invalid_noflush(page, 1); > > + if (ret) > > + goto err_del_page_cache; > > + > > + addr = (unsigned long)page_address(page); > > + flush_tlb_kernel_range(addr, addr + PAGE_SIZE); > > + > > + __SetPageUptodate(page); > > + > > + ret = VM_FAULT_LOCKED; > > + } > > + > > + vmf->page = page; > > + return ret; > > Does sparse not warn you about this abuse of vm_fault_t? Separate out > 'ret' and 'err'. Will fix. > Andrew, please fold in this fix. I suspect Mike will want to fix > the other things I mention above. > > diff --git a/mm/secretmem.c b/mm/secretmem.c > index 3dfdbd85ba00..09ca27f21661 100644 > --- a/mm/secretmem.c > +++ b/mm/secretmem.c > @@ -172,7 +172,7 @@ static vm_fault_t secretmem_fault(struct vm_fault *vmf) > if (((loff_t)vmf->pgoff << PAGE_SHIFT) >= i_size_read(inode)) > return vmf_error(-EINVAL); > > - page = find_get_entry(mapping, offset); > + page = find_get_page(mapping, offset); > if (!page) { > page = secretmem_alloc_page(ctx, vmf->gfp_mask); > if (!page) -- Sincerely yours, Mike.