From patchwork Tue Apr 20 13:16:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Rapoport X-Patchwork-Id: 12214265 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=-17.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 30965C433B4 for ; Tue, 20 Apr 2021 13:17:40 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 76A3B60BD3 for ; Tue, 20 Apr 2021 13:17:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 76A3B60BD3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=y1K3VOAzyzanFYxLoH5BaUpYumzJAVgR/9aD64ZeciU=; b=oswDIUgAPj8m99TiE66ciyeGq 46c4/ZFsdwaixrexV3q1dAiyLYE+UVJKNWcGYRud1fgGnrdlreb4ghfhVbomWkzKGVHQb7CtsRPJi C7E7arsn9eexQRc6V8D/lHd0EcVxBV2Q2bkuU0ViheeqYrom5f3bmpvA26H+7gPvvDQ11MJvvYfyK LaqWJHooe2zd2rrLrzLca/Fj9s0e0VJCUQYL9fQO2k//QX1zKsHupeXIECb+O31im6Vwdjx8lyyFi StIi2iYJhR5piH5q/ijQzndYXzYG/JNNtBy8ZT/4nljPm7CboKAuLOIudG5Jm2Mk17hI9tLpYZEXa acvb0hwxg==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lYqFu-00CBIT-L1; Tue, 20 Apr 2021 13:17:30 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lYqFX-00CBC5-20; Tue, 20 Apr 2021 13:17:07 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender :Reply-To:Content-Type:Content-ID:Content-Description; bh=2UiMd1x2iPg5BHSmMMcJrxFoD7KyHYuCPHs/JKxkkTI=; b=TC3+I8xWTuJNoQ2HJUk8oNCgrh UzUQm5OVUgYDGaXdRCo+hbYXreIIBfkCOXTFV4J83WYPo/qKjNMrsj7SbGLWvlB9Abuywsw72YipZ osV4sumbZ3dCXYb1NKnKC9GADrtTYE/JGKtIVual1isz7n0UhCMxotyJFFprLPxM26oJfItkhOtMJ wsFhnoW1AdDx5TN2iIgNTl5X91GiulM0Sx2mhBO1dgveEw9GwLHh5K2Y15qE1YccS0hqrQfdHYTjv nGhhfF+JnxhxhFFEfCzlk6q3apwO2XJgZxiPSH9ODWVlonm79A7MfXu2slTxfymDAk6fFDmZYjV1t P/9idRuw==; Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lYqFS-00C8I2-S5; Tue, 20 Apr 2021 13:17:05 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id A58626101C; Tue, 20 Apr 2021 13:16:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1618924622; bh=WQBjtjBUVixKPUq09lDhJ2RWgVokupnypM/eycKpBe4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o20bjAEWBJIEF1h8/qnesID8pJlsOtYuQBEFthZNIuah5vjhGL7mYjpmIzPheyOx4 zLmqEbpr2OKL7I9OmN22sKr2N7ibr2TrEl5aMvAOxoDBtPZqdRTGpZoyJ2PJqkfxJV Qbxe7kAtQvCe0Cszrfy03TeNMo4aOoMIbPjQ/IhtksgBNK+KbWwn5JjkQyeTlh+9GW 7ayegBRJ7F9EeOZgbRVUmdGD+Gtl0pbyUlvLoUAxk3zVPW/ZgQB24WZZ3cq+M4yt5b cS+Z7QvAnRl9GQRZmMTOmd34XlEqDq8drJq7x8VbwE6eT/oQpXisCqiOOov/gnN9P+ LmH3i4FuAUXpw== From: Mike Rapoport To: Andrew Morton Cc: 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 Wilcox , Matthew Garrett , Mark Rutland , Michal Hocko , Mike Rapoport , 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 Subject: [PATCH v2 2/2] secretmem/gup: don't check if page is secretmem without reference Date: Tue, 20 Apr 2021 16:16:10 +0300 Message-Id: <20210420131611.8259-4-rppt@kernel.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20210420131611.8259-1-rppt@kernel.org> References: <20210420131611.8259-1-rppt@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210420_061702_990329_F90ACA41 X-CRM114-Status: GOOD ( 13.33 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org From: Mike Rapoport The check in gup_pte_range() whether a page belongs to a secretmem mapping is performed before grabbing the page reference. To avoid potential race move the check after try_grab_compound_head(). Signed-off-by: Mike Rapoport --- mm/gup.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index c3a17b189064..4b58c016e949 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2080,13 +2080,13 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, 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; + if (page_is_secretmem(page)) + goto pte_unmap; + if (unlikely(pte_val(pte) != pte_val(*ptep))) { put_compound_head(head, 1, flags); goto pte_unmap;