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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 629E8C43461 for ; Fri, 4 Sep 2020 10:36:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 39D05206B8 for ; Fri, 4 Sep 2020 10:36:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730116AbgIDKfx (ORCPT ); Fri, 4 Sep 2020 06:35:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:51654 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730137AbgIDKbV (ORCPT ); Fri, 4 Sep 2020 06:31:21 -0400 Received: from localhost.localdomain (unknown [46.69.195.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3A1502145D; Fri, 4 Sep 2020 10:30:50 +0000 (UTC) From: Catalin Marinas To: linux-arm-kernel@lists.infradead.org Cc: linux-mm@kvack.org, linux-arch@vger.kernel.org, Will Deacon , Dave P Martin , Vincenzo Frascino , Szabolcs Nagy , Kevin Brodsky , Andrey Konovalov , Peter Collingbourne , Andrew Morton Subject: [PATCH v9 08/29] mm: Preserve the PG_arch_2 flag in __split_huge_page_tail() Date: Fri, 4 Sep 2020 11:30:08 +0100 Message-Id: <20200904103029.32083-9-catalin.marinas@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200904103029.32083-1-catalin.marinas@arm.com> References: <20200904103029.32083-1-catalin.marinas@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-arch-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org When a huge page is split into normal pages, part of the head page flags are transferred to the tail pages. However, the PG_arch_* flags are not part of the preserved set. PG_arch_2 is used by the arm64 MTE support to mark pages that have valid tags. The absence of such flag would cause the arm64 set_pte_at() to clear the tags in order to avoid stale tags exposed to user or the swapping out hooks to ignore the tags. Not preserving PG_arch_2 on huge page splitting leads to tag corruption in the tail pages. Preserve the newly added PG_arch_2 flag in __split_huge_page_tail(). Signed-off-by: Catalin Marinas Cc: Andrew Morton --- Notes: v7: - Only preserve PG_arch_2 in __split_huge_page_tail(). The PG_arch_1 flag will be discussed separately as it may potentially impact s390 and x86. New in v6. mm/huge_memory.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 2ccff8472cd4..1a5773c95f53 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2337,6 +2337,9 @@ static void __split_huge_page_tail(struct page *head, int tail, (1L << PG_workingset) | (1L << PG_locked) | (1L << PG_unevictable) | +#ifdef CONFIG_64BIT + (1L << PG_arch_2) | +#endif (1L << PG_dirty))); /* ->mapping in first tail page is compound_mapcount */