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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 C575EC2B9F4 for ; Mon, 28 Jun 2021 14:28:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8474061C9A for ; Mon, 28 Jun 2021 14:28:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234176AbhF1O3O (ORCPT ); Mon, 28 Jun 2021 10:29:14 -0400 Received: from mail.kernel.org ([198.145.29.99]:54978 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233583AbhF1OXS (ORCPT ); Mon, 28 Jun 2021 10:23:18 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0555F619BE; Mon, 28 Jun 2021 14:20:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1624890013; bh=Iccst4KppGKs+kdGBsjSRh89VuizfARuSzZGsoEThrI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=urRbsDHtjI8iaNfbgsl+Ayy+U6+QHO8knRJ74edb5qcgqSBaikKyUzqqCz4YEjVB5 XgdIlhI0fjuaSohJf7URWzPUONcf52DJF5/t65z0JcOTwILhX2AhaD/SC3mCI18Xj0 x8EnRVVFUGwY8wuymVyBDXJDtDmw4SaG2C3sWOATVKXO0TjAZTmqW3OJCNU0qLbNx0 tqi+kz0gn5RStSUu9Kbbkos+n54Kaen3bnTx/d4sh3IwvI79PEKjlYKppWnJTZOOTA VJAg12m9HvA3/unypL5wfIusiHJtxWO4MLnXCHnrTY7SLRyGCyo0WBOhrNGRXSjkFb 9h/PitSt+v2qw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Hugh Dickins , "Kirill A . Shutemov" , Wang Yugui , Alistair Popple , Matthew Wilcox , Peter Xu , Ralph Campbell , Will Deacon , Yang Shi , Zi Yan , Andrew Morton , Linus Torvalds , Greg Kroah-Hartman Subject: [PATCH 5.12 099/110] mm/thp: another PVMW_SYNC fix in page_vma_mapped_walk() Date: Mon, 28 Jun 2021 10:18:17 -0400 Message-Id: <20210628141828.31757-100-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210628141828.31757-1-sashal@kernel.org> References: <20210628141828.31757-1-sashal@kernel.org> MIME-Version: 1.0 X-KernelTest-Patch: http://kernel.org/pub/linux/kernel/v5.x/stable-review/patch-5.12.14-rc1.gz X-KernelTest-Tree: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git X-KernelTest-Branch: linux-5.12.y X-KernelTest-Patches: git://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git X-KernelTest-Version: 5.12.14-rc1 X-KernelTest-Deadline: 2021-06-30T14:18+00:00 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Hugh Dickins commit a7a69d8ba88d8dcee7ef00e91d413a4bd003a814 upstream. Aha! Shouldn't that quick scan over pte_none()s make sure that it holds ptlock in the PVMW_SYNC case? That too might have been responsible for BUGs or WARNs in split_huge_page_to_list() or its unmap_page(), though I've never seen any. Link: https://lkml.kernel.org/r/1bdf384c-8137-a149-2a1e-475a4791c3c@google.com Link: https://lore.kernel.org/linux-mm/20210412180659.B9E3.409509F4@e16-tech.com/ Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()") Signed-off-by: Hugh Dickins Acked-by: Kirill A. Shutemov Tested-by: Wang Yugui Cc: Alistair Popple Cc: Matthew Wilcox Cc: Peter Xu Cc: Ralph Campbell Cc: Will Deacon Cc: Yang Shi Cc: Zi Yan Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/page_vma_mapped.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c index 16f139f83ebf..3350faeb199a 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -276,6 +276,10 @@ next_pte: goto restart; } pvmw->pte++; + if ((pvmw->flags & PVMW_SYNC) && !pvmw->ptl) { + pvmw->ptl = pte_lockptr(mm, pvmw->pmd); + spin_lock(pvmw->ptl); + } } while (pte_none(*pvmw->pte)); if (!pvmw->ptl) { -- 2.30.2