From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f197.google.com (mail-wr0-f197.google.com [209.85.128.197]) by kanga.kvack.org (Postfix) with ESMTP id 03C636B0006 for ; Wed, 21 Feb 2018 07:01:48 -0500 (EST) Received: by mail-wr0-f197.google.com with SMTP id 62so1256622wrg.0 for ; Wed, 21 Feb 2018 04:01:47 -0800 (PST) Received: from huawei.com (lhrrgout.huawei.com. [194.213.3.17]) by mx.google.com with ESMTPS id m25si1768505edb.219.2018.02.21.04.01.46 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 21 Feb 2018 04:01:46 -0800 (PST) Subject: Re: [PATCH 3/6] struct page: add field for vm_struct References: <20180211031920.3424-1-igor.stoppa@huawei.com> <20180211031920.3424-4-igor.stoppa@huawei.com> <20180211211646.GC4680@bombadil.infradead.org> <20180220205442.GA15973@bombadil.infradead.org> From: Igor Stoppa Message-ID: Date: Wed, 21 Feb 2018 14:01:20 +0200 MIME-Version: 1.0 In-Reply-To: <20180220205442.GA15973@bombadil.infradead.org> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Matthew Wilcox Cc: rdunlap@infradead.org, corbet@lwn.net, keescook@chromium.org, mhocko@kernel.org, labbott@redhat.com, jglisse@redhat.com, hch@infradead.org, cl@linux.com, linux-security-module@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com On 20/02/18 22:54, Matthew Wilcox wrote: > On Tue, Feb 20, 2018 at 09:53:30PM +0200, Igor Stoppa wrote: [...] >> It was found while testing on a configuration with framebuffer. > > ... ah. You tried to use vmalloc_to_page() on something which wasn't > backed by a struct page. That's *supposed* to return NULL, but my > guess is that after this patch it returned garbage. it seems to return garbage also without this patch, but I need to clean up the code, try it again and possibly come up with a demo patch for triggering the problem. I'll investigate it more. However it doesn't seem to be related to the functionality I need. So I plan to treat it as separate issue and leave find_vm_area untouched, at least in pmalloc scope. -- igor -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org