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=-23.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL 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 30F11C47094 for ; Thu, 10 Jun 2021 06:56:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E956613DE for ; Thu, 10 Jun 2021 06:56:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229943AbhFJG6C (ORCPT ); Thu, 10 Jun 2021 02:58:02 -0400 Received: from mail-qt1-f178.google.com ([209.85.160.178]:45572 "EHLO mail-qt1-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229778AbhFJG6B (ORCPT ); Thu, 10 Jun 2021 02:58:01 -0400 Received: by mail-qt1-f178.google.com with SMTP id l17so16016563qtq.12 for ; Wed, 09 Jun 2021 23:55:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :mime-version; bh=zujSa+nymJg/DkygOzBqfFRpvoPGGLvQoUzC9rD2EmM=; b=d+CHzx9kx2FW5+g+wRTEglrZHDD2va0NJeQznMTqavHkJKp8sIQAoV4Xl6VPkL/21a GQeN3iyeoaNEmvPVwRrrGCrG6C8d6PZbBDxVmEyxIgTXugm3GmBDemitSpPAF8c4I8iU rhlfqQRvxv244TvuzRX2C190uZyOlY5zGSVwvdz2Zs7F9UAZyU3xADhczznWRvYlpZRm ALXo36ZKcmd8MTCNDLR51p1ZO9TF30Cg1VH7dw7T7Z44WunIOIV9cIhr9+rsiNeG4/VS UtwMtJ8r4/tj/Vmp+gDCrtzjuM3wf6vtEeN27WC6LLMmQZXQPKpKPv3YKoKpS9NpptTM 0XdQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version; bh=zujSa+nymJg/DkygOzBqfFRpvoPGGLvQoUzC9rD2EmM=; b=sQELR0OKM+30Ktu/ayRrZlw6MI8m3Qk2crf0t7t+Wka3UoEF+xJOwqMK0/G2Y9qtSa 7JrVhdFz8bWPIsIIRRkwcE/EMcaxOub44gpElhyShEHu37Nc6uAgLES0+grNYivpweRs vpsBLOJgfc6fHa/gldI+MtXYmdd4HDwW0FemSoPfmhomyhdwYjbtyx7spe8QaQ5HoqPP tF1jJoV60w/vFI4CNjwiSDZPyX+i4ifKuaMg+EFNe7VuQcbW+HKRY6oM9yh1Cx7sCHZq Wmunlqy40Rw6ceS9LQmgbOGEmzsHb5XM0o2QsnIXA412LXd2AzPWRnAkiVi0Y5SnlJwl KQew== X-Gm-Message-State: AOAM533pB6LderD/dx/jXKj+VMOtULLZLFb4L72pilnKH2104o+yEo9u DmDEXoXCdWrzamtGsostwHn5Cg== X-Google-Smtp-Source: ABdhPJyWmrIYtT3Hki5va0KGk1YyG5yE6G/KbTu0XqJoO/SiXciAA8VL5O7uhLNqek19ZMtnb91BBw== X-Received: by 2002:ac8:47c2:: with SMTP id d2mr3771672qtr.128.1623308088731; Wed, 09 Jun 2021 23:54:48 -0700 (PDT) Received: from ripple.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id u3sm1611578qtg.16.2021.06.09.23.54.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 09 Jun 2021 23:54:48 -0700 (PDT) Date: Wed, 9 Jun 2021 23:54:46 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@ripple.anvils To: Andrew Morton cc: Hugh Dickins , "Kirill A. Shutemov" , Yang Shi , Wang Yugui , Matthew Wilcox , Alistair Popple , Ralph Campbell , Zi Yan , Peter Xu , Will Deacon , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 11/11] mm/thp: another PVMW_SYNC fix in page_vma_mapped_walk() In-Reply-To: <589b358c-febc-c88e-d4c2-7834b37fa7bf@google.com> Message-ID: <1bdf384c-8137-a149-2a1e-475a4791c3c@google.com> References: <589b358c-febc-c88e-d4c2-7834b37fa7bf@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()") Signed-off-by: Hugh Dickins Cc: --- 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 6eb2f1863506..7ae4a016304b 100644 --- a/mm/page_vma_mapped.c +++ b/mm/page_vma_mapped.c @@ -277,6 +277,10 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw) 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) { -- 2.26.2