From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x226t4bENawRuXV59fFlt0COjUO9Ql4IVqXw53sJKOGNwG6rjIg+mpD93klBfWmRGoBviBRzQ ARC-Seal: i=1; a=rsa-sha256; t=1519214524; cv=none; d=google.com; s=arc-20160816; b=kbZtdFXEoIg9M8bOzwV7fsaIr7gJdC6+ilDQdONWKRetD02PB7YmhAVTSd2qCnS5SS aquKW7Bt74GkLnQNvlkRBPGL6bRUD3Gr3wEusPNTQq0QBjc9/0cHITWghseWU/ZPMrmo RH1VEJmqN9rZyYIAxnz/cSpNYuLH3klx2j8fDVGu0OcSfaDaHzi8Pee7JGvWut3ajiSd t+Nkmj324klQVsVat0P/ZXsOO/XxIT4017hmB09QwqP0qNyQN32TehkQJCztPJ3v78jS sH05Y3WoVXGNVTu+S/+1TgDCT7ke7ba+Sz7OLJJ7G+8ZAJ+oZCXmic3u/c13BMov2vcl qWSA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject :delivered-to:list-id:list-subscribe:list-unsubscribe:list-help :list-post:precedence:mailing-list:arc-authentication-results; bh=Eywmp9abR1RtY2zl0ikfAcRDEGiiYw7KYmkvq5otBKM=; b=xsnZ6sA0pXafCRUpk2EFUmkAhI3MYOm1Rx27uDgKY+eDjEKttJUAByhv+Xarmz2O/U sX3Q8yFjyAK+14NkXOmOFGWfi9d5hDgwF8BWcr90X035KNsiL38Kn+U8JCW3M/N46Fa3 KRA8XlrKaFg+jFYFI1PUkHiBTNvJj8NQ77v2LrwygpOig0pCKioPaosVk/K95eix/ZAT hvWJrPCVIAPRlX3bXUtK/XzmqxHhdzJfY7D3jh+SUyy6ft3RLljHTfScDsplYO3+Gh4m AhA/aiTNVB7+MEfxFsVtmKuUFEuHU7KdiWBq9v5EZpZ5K8tg+Hy8ei94TF+EYQkiV6OI fKsQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of kernel-hardening-return-11854-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-11854-gregkh=linuxfoundation.org@lists.openwall.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of kernel-hardening-return-11854-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-11854-gregkh=linuxfoundation.org@lists.openwall.com Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm List-Post: List-Help: List-Unsubscribe: List-Subscribe: Subject: Re: [PATCH 3/6] struct page: add field for vm_struct To: Matthew Wilcox CC: , , , , , , , , , , , 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 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 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 X-Originating-IP: [10.122.225.51] X-CFilter-Loop: Reflected X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1592073184128407406?= X-GMAIL-MSGID: =?utf-8?q?1593011889375359627?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 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