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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,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 F0096C433B4 for ; Mon, 19 Apr 2021 11:27:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7EB87601FD for ; Mon, 19 Apr 2021 11:27:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7EB87601FD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 04D3E6B0036; Mon, 19 Apr 2021 07:27:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F179E6B006E; Mon, 19 Apr 2021 07:27:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D6A4B6B0070; Mon, 19 Apr 2021 07:27:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0119.hostedemail.com [216.40.44.119]) by kanga.kvack.org (Postfix) with ESMTP id B7D316B0036 for ; Mon, 19 Apr 2021 07:27:22 -0400 (EDT) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 6D1E7181AEF3F for ; Mon, 19 Apr 2021 11:27:22 +0000 (UTC) X-FDA: 78048890724.06.92E8E48 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf09.hostedemail.com (Postfix) with ESMTP id 7BC42600011F for ; Mon, 19 Apr 2021 11:27:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=8kRAoc0QBubKYge5PVOcpXOSqRAXAMW8YeZW9/WtJU8=; b=Q4iGwzjsJleF1GjQOjyti4BwEQ kMflgbMlKiSgpC29OgqfVgGrZttP1HwPBGt8N93ehv3ya+xnOskH/kBy+D0N5vT5yUe/+g1v9z/Ma Cp4tIDAseOedgjInQg5yHqOEvZbooQDFHeYs8Sryde6A4fQ5slcDMthytLKrH2OJz/4qJDzam9eBn p6bjarnH+CdB1hRK/wAvjCp96Ow2EiDF9/3ydKwZwqane+/kvenBjEPU7O5eAiYLGTdXKzhzt0PGo DvZtg4i6iUXZmGxEIMN7nGJNjQ60ITQJypATNUfusbk15xxeHMt+n9rKsreyAJad/2eA7Z5Mlaiyn rBuUX32A==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lYRza-00Dec0-Ty; Mon, 19 Apr 2021 11:23:12 +0000 Date: Mon, 19 Apr 2021 12:23:02 +0100 From: Matthew Wilcox To: Mike Rapoport 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" , Matthew Garrett , Mark Rutland , Michal Hocko , Mike Rapoport , Michael Kerrisk , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , "Rafael J. Wysocki" , Rick Edgecombe , Roman Gushchin , Shakeel Butt , Shuah Khan , Thomas Gleixner , Tycho Andersen , Will Deacon , Yury Norov , 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, kernel test robot Subject: Re: [PATCH] secretmem: optimize page_is_secretmem() Message-ID: <20210419112302.GX2531743@casper.infradead.org> References: <20210419084218.7466-1-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210419084218.7466-1-rppt@kernel.org> X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 7BC42600011F X-Stat-Signature: h7h6f4o6hbeo41wnxk44ifmexrfj89hh Received-SPF: none (infradead.org>: No applicable sender policy available) receiver=imf09; identity=mailfrom; envelope-from=""; helo=casper.infradead.org; client-ip=90.155.50.34 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1618831637-756318 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 Mon, Apr 19, 2021 at 11:42:18AM +0300, Mike Rapoport wrote: > The perf profile of the test indicated that the regression is caused by > page_is_secretmem() called from gup_pte_range() (inlined by gup_pgd_range): Uhh ... you're calling it in the wrong place! VM_BUG_ON(!pfn_valid(pte_pfn(pte))); page = pte_page(pte); if (page_is_secretmem(page)) goto pte_unmap; head = try_grab_compound_head(page, 1, flags); if (!head) goto pte_unmap; So you're calling page_is_secretmem() on a struct page without having a refcount on it. That is definitely not allowed. secretmem seems to be full of these kinds of races; I know this isn't the first one I've seen in it. I don't think this patchset is ready for this merge window. With that fixed, you'll have a head page that you can use for testing, which means you don't need to test PageCompound() (because you know the page isn't PageTail), you can just test PageHead().