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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 294DEC4167D for ; Mon, 23 May 2022 17:39:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242225AbiEWRh0 (ORCPT ); Mon, 23 May 2022 13:37:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241305AbiEWR0l (ORCPT ); Mon, 23 May 2022 13:26:41 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 05C976C0CC; Mon, 23 May 2022 10:21:38 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A2AAE61157; Mon, 23 May 2022 17:20:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A73A3C385A9; Mon, 23 May 2022 17:20:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1653326426; bh=xZXm9hxyr42KzqGtHutUC98ZI1vmCDUMDb8TdOKvfkI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ialM3F9CuKkej3cLQpirgtD3csxe/I32VP22Vz3bHtDPS2LdY3tMXBjKvdsZhqb7y 3/w98S1p14M1b5/iljYjn53s4khhgPDldODXzE/GMPB4QEP6SBVCyAKe7LQE9fL57G DJTDEfaSHeQOZkStPmxdHqm8AD+pcqgpvNnn/x9s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Catalin Marinas , Vladimir Murzin , Will Deacon , Steven Price Subject: [PATCH 5.15 054/132] arm64: mte: Ensure the cleared tags are visible before setting the PTE Date: Mon, 23 May 2022 19:04:23 +0200 Message-Id: <20220523165832.235944269@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220523165823.492309987@linuxfoundation.org> References: <20220523165823.492309987@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Catalin Marinas commit 1d0cb4c8864addc362bae98e8ffa5500c87e1227 upstream. As an optimisation, only pages mapped with PROT_MTE in user space have the MTE tags zeroed. This is done lazily at the set_pte_at() time via mte_sync_tags(). However, this function is missing a barrier and another CPU may see the PTE updated before the zeroed tags are visible. Add an smp_wmb() barrier if the mapping is Normal Tagged. Signed-off-by: Catalin Marinas Fixes: 34bfeea4a9e9 ("arm64: mte: Clear the tags when a page is mapped in user-space with PROT_MTE") Cc: # 5.10.x Reported-by: Vladimir Murzin Cc: Will Deacon Reviewed-by: Steven Price Tested-by: Vladimir Murzin Link: https://lore.kernel.org/r/20220517093532.127095-1-catalin.marinas@arm.com Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/mte.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -73,6 +73,9 @@ void mte_sync_tags(pte_t old_pte, pte_t mte_sync_page_tags(page, old_pte, check_swap, pte_is_tagged); } + + /* ensure the tags are visible before the PTE is set */ + smp_wmb(); } int memcmp_pages(struct page *page1, struct page *page2)