From patchwork Tue Nov 3 18:17:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 317243 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=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 B0B99C388F9 for ; Tue, 3 Nov 2020 18:17:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5DCC422264 for ; Tue, 3 Nov 2020 18:17:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604427422; bh=WEtXOWE1xtG4/g8Lhug1ADD82+cZ0V/XgIGg1k7XHcs=; h=Date:From:To:Subject:List-ID:From; b=aEtkC0R1SKhxd4/XIiPYbkeEdjCYZW3r7+L0bHgOAWdsaHuBRUyTihNtVlMiM94Zw Hd2aWUQTtQDV7CWSExV7Gw1dTkDT1Y8++WMSf0ZjCGyQLWAnlNKq0yHgj0Vf+gvRTN m0+O3OE/W5BYaj1xsavaSdA3botLFt5TuCLbwpc8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729244AbgKCSRB (ORCPT ); Tue, 3 Nov 2020 13:17:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:39404 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725385AbgKCSRB (ORCPT ); Tue, 3 Nov 2020 13:17:01 -0500 Received: from localhost.localdomain (c-71-198-47-131.hsd1.ca.comcast.net [71.198.47.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AAF3C207BB; Tue, 3 Nov 2020 18:17:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604427421; bh=WEtXOWE1xtG4/g8Lhug1ADD82+cZ0V/XgIGg1k7XHcs=; h=Date:From:To:Subject:From; b=WWgWq0xO/cxR3MZA//gHUBX1Z+twp0UP+9IhOXeX6cwHoZ9J+9PT3lHqSVObdF7Tu 4GhxaNE3aFGEQiXGEqitkVkk0uGhYbY1zcAK/1AKFtPcOIO/EmGkvOtWhWnxBJQj3R 35xLh4ZuVVoVBlNYwaye8aUo1dNTaNb2wxeedJQo= Date: Tue, 03 Nov 2020 10:17:00 -0800 From: akpm@linux-foundation.org To: linfeilong@huawei.com, linmiaohe@huawei.com, luoshijie1@huawei.com, mhocko@suse.com, mm-commits@vger.kernel.org, osalvador@suse.de, stable@vger.kernel.org Subject: [merged] mm-mempolicy-fix-potential-pte_unmap_unlock-pte-error.patch removed from -mm tree Message-ID: <20201103181700.9blVqSSEg%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch titled Subject: mm: mempolicy: fix potential pte_unmap_unlock pte error has been removed from the -mm tree. Its filename was mm-mempolicy-fix-potential-pte_unmap_unlock-pte-error.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Shijie Luo Subject: mm: mempolicy: fix potential pte_unmap_unlock pte error When flags in queue_pages_pte_range don't have MPOL_MF_MOVE or MPOL_MF_MOVE_ALL bits, code breaks and passing origin pte - 1 to pte_unmap_unlock seems like not a good idea. queue_pages_pte_range can run in MPOL_MF_MOVE_ALL mode which doesn't migrate misplaced pages but returns with EIO when encountering such a page. Since commit a7f40cfe3b7a ("mm: mempolicy: make mbind() return -EIO when MPOL_MF_STRICT is specified") and early break on the first pte in the range results in pte_unmap_unlock on an underflow pte. This can lead to lockups later on when somebody tries to lock the pte resp. page_table_lock again.. Link: https://lkml.kernel.org/r/20201019074853.50856-1-luoshijie1@huawei.com Fixes: a7f40cfe3b7a ("mm: mempolicy: make mbind() return -EIO when MPOL_MF_STRICT is specified") Signed-off-by: Shijie Luo Signed-off-by: Miaohe Lin Reviewed-by: Oscar Salvador Acked-by: Michal Hocko Cc: Miaohe Lin Cc: Feilong Lin Cc: Shijie Luo Cc: Signed-off-by: Andrew Morton --- mm/mempolicy.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/mm/mempolicy.c~mm-mempolicy-fix-potential-pte_unmap_unlock-pte-error +++ a/mm/mempolicy.c @@ -525,7 +525,7 @@ static int queue_pages_pte_range(pmd_t * unsigned long flags = qp->flags; int ret; bool has_unmovable = false; - pte_t *pte; + pte_t *pte, *mapped_pte; spinlock_t *ptl; ptl = pmd_trans_huge_lock(pmd, vma); @@ -539,7 +539,7 @@ static int queue_pages_pte_range(pmd_t * if (pmd_trans_unstable(pmd)) return 0; - pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); + mapped_pte = pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); for (; addr != end; pte++, addr += PAGE_SIZE) { if (!pte_present(*pte)) continue; @@ -571,7 +571,7 @@ static int queue_pages_pte_range(pmd_t * } else break; } - pte_unmap_unlock(pte - 1, ptl); + pte_unmap_unlock(mapped_pte, ptl); cond_resched(); if (has_unmovable)