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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 B2526C3F2CE for ; Tue, 17 Mar 2020 11:49:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 688BD206EC for ; Tue, 17 Mar 2020 11:49:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="eWdg7Fuu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 688BD206EC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 11E556B0005; Tue, 17 Mar 2020 07:49:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0CFFD6B0006; Tue, 17 Mar 2020 07:49:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F267B6B0007; Tue, 17 Mar 2020 07:49:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0187.hostedemail.com [216.40.44.187]) by kanga.kvack.org (Postfix) with ESMTP id D7A5A6B0005 for ; Tue, 17 Mar 2020 07:49:49 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 97FC24DC0 for ; Tue, 17 Mar 2020 11:49:49 +0000 (UTC) X-FDA: 76604684898.29.arm08_72dc5bcaf7d2c X-HE-Tag: arm08_72dc5bcaf7d2c X-Filterd-Recvd-Size: 5374 Received: from mail-pf1-f195.google.com (mail-pf1-f195.google.com [209.85.210.195]) by imf42.hostedemail.com (Postfix) with ESMTP for ; Tue, 17 Mar 2020 11:49:49 +0000 (UTC) Received: by mail-pf1-f195.google.com with SMTP id 23so11839036pfj.1 for ; Tue, 17 Mar 2020 04:49:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=MMK1oa7caM4FxenuRyA9kQAaY+A0jvSFKtsdxSSnm50=; b=eWdg7FuuLGf/HHPeZutN/DYRjxENPqg+VeIJz4NbSKSfjLv6CdrPv1RzaD/qLOir2Q o+m1Vv+PqzjYMbFY9kaagOU+qtTyfg4RlKmjpWxxLEPRKSntm60Tq+pfugBkVK2eEDys mtrpofcDQ4D2Liywttc4FNG5G4izeWiVb8XhS5nyi1kdMOk+e1jPYs2EsMRyDt6E+gYd rsj0ADZq9uqh5L0OQf4YtYG2gg/gxwRktAOLGWNGKhSHWs2XEb/noOsL+84foC2leXf9 PVLStKZBVq3AdMHy3m6wjUUirFfwqhGtT1BICQOcF9oCrYFb4ncRIXiLzy6UbWZ9jZib CCTA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=MMK1oa7caM4FxenuRyA9kQAaY+A0jvSFKtsdxSSnm50=; b=AzCu9y8e07wZed/KpBymIhV3KgJY670u8tF4ZXpaSRAVnLtyILfOEa7fWuyOVMWUI3 r2LMraLc+WGULp3TOfCz6YRONw/mYsyolDVorffvirGYHgGsvzbzyZvncpVKLfQKyDer BF2nYwQt9ZLsifDD1Vsb6O/VgJnb17G4YPxVMVchKrf4xfnABMHm/t2Jxlrkwf3KEsfK NCKiFL45FG56nU6ofe11IF3jn6m/6CUDN+Nh9300AbKAL6ldHkVLKYJBM9snpQr0lZkL IPmfBQxeEZn5460W1x9nMamO3Oc1dpXk9HcXpQlaWQebnun6k5ZmE0zOj39lcvRnZnJn 0Obw== X-Gm-Message-State: ANhLgQ1z8P4QdbSWlczy7EVTIoH4/ZxZOO/QFN5xW13x/5M0vy7WCaHS qNOmawhIbDxXQjPPzHuD3X8vzTg= X-Google-Smtp-Source: ADFU+vs30UmxxLczix5J155deIGMh7kh1xX+QCQHAyX7Z38r2hTSjuVeqqLeG6kvUoSxB6CfWyEfHg== X-Received: by 2002:a62:3854:: with SMTP id f81mr4823792pfa.81.1584445787852; Tue, 17 Mar 2020 04:49:47 -0700 (PDT) Received: from mylaptop.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id c62sm2214845pfc.136.2020.03.17.04.49.42 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 17 Mar 2020 04:49:47 -0700 (PDT) From: Pingfan Liu To: linux-mm@kvack.org Cc: Pingfan Liu , Ira Weiny , Andrew Morton , Mike Rapoport , Dan Williams , Matthew Wilcox , John Hubbard , "Aneesh Kumar K.V" , Christoph Hellwig , Shuah Khan , Jason Gunthorpe , linux-kernel@vger.kernel.org Subject: [PATCHv7 2/3] mm/gup: fix omission of check on FOLL_LONGTERM in gup fast path Date: Tue, 17 Mar 2020 19:47:32 +0800 Message-Id: <1584445652-30064-1-git-send-email-kernelfans@gmail.com> X-Mailer: git-send-email 2.7.5 In-Reply-To: <1584333244-10480-3-git-send-email-kernelfans@gmail.com> References: <1584333244-10480-3-git-send-email-kernelfans@gmail.com> 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: FOLL_LONGTERM is a special case of FOLL_PIN. It suggests a pin which is going to be given to hardware and can't move. It would truncate CMA permanently and should be excluded. In gup slow path, slow path, where __gup_longterm_locked->check_and_migrate_cma_pages() handles FOLL_LONGTERM, but in fast path, there lacks such a check, which means a possible leak of CMA page to longterm pinned. Place a check in try_grab_compound_head() in the fast path to fix the leak, and if FOLL_LONGTERM happens on CMA, it will fall back to slow path to migrate the page. Some note about the check: Huge page's subpages have the same migrate type due to either allocation from a free_list[] or alloc_contig_range() with param MIGRATE_MOVABLE. So it is enough to check on a single subpage by is_migrate_cma_page(subpage) Signed-off-by: Pingfan Liu Cc: Ira Weiny Cc: Andrew Morton Cc: Mike Rapoport Cc: Dan Williams Cc: Matthew Wilcox Cc: John Hubbard Cc: "Aneesh Kumar K.V" Cc: Christoph Hellwig Cc: Shuah Khan Cc: Jason Gunthorpe To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- v6 -> v7: fix coding style issue mm/gup.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/mm/gup.c b/mm/gup.c index 9df77b1..0a536d7 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -89,6 +89,15 @@ static __maybe_unused struct page *try_grab_compound_head(struct page *page, int orig_refs = refs; /* + * Huge page's subpages have the same migrate type due to either + * allocation from a free_list[] or alloc_contig_range() with + * param MIGRATE_MOVABLE. So it is enough to check on a subpage. + */ + if (unlikely(flags & FOLL_LONGTERM) && + is_migrate_cma_page(page)) + return NULL; + + /* * When pinning a compound page of order > 1 (which is what * hpage_pincount_available() checks for), use an exact count to * track it, via hpage_pincount_add/_sub(). -- 2.7.5