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=-17.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL 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 2EDE7C5B578 for ; Tue, 2 Jul 2019 00:51:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EB3DF21473 for ; Tue, 2 Jul 2019 00:51:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="ODdYbhrZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727110AbfGBAvv (ORCPT ); Mon, 1 Jul 2019 20:51:51 -0400 Received: from mail-pf1-f201.google.com ([209.85.210.201]:34440 "EHLO mail-pf1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726866AbfGBAvv (ORCPT ); Mon, 1 Jul 2019 20:51:51 -0400 Received: by mail-pf1-f201.google.com with SMTP id i2so9811814pfe.1 for ; Mon, 01 Jul 2019 17:51:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=fQRHpcnZQgmJ5EVYhy+Qqag9BuKV3GgR0RmH9DgVc30=; b=ODdYbhrZxLaj82QT81sQFex0PsUNmi7pkBfxxjI2BAqvUgbT1v5TtvMslVPTu/mUMp MnvG9TO9zNsxpUFKLqftjjjMTJsVYPqjIOmm2oNV41LiRHkjdcA3EKJ4EbQnS5uiPQfM Zpt0Pu7BsCzYycwnA83E8hGzxksbyCLMMp8GvRlzJdjwyfjNUsSW86ZNgnExlTFI0clR lrPk2JAuiLERvcNdFXCFwo9a7auujyK/+AtWsKFveHTrcIEjmeUqdfcQw+WmGs8kjTjm NrDfELXrRp/baVJbjHvlkgBpNBTz6IjR4P+aaniPxlvNq/kvztmSoJu5gT1ZU+y8IjCW UEJQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=fQRHpcnZQgmJ5EVYhy+Qqag9BuKV3GgR0RmH9DgVc30=; b=ORm9Ub9JYC1aJEwhZRri0aeLuOgBhfxp+fic1fv+H/NgjzkJ450+CpZb0lKPDfmxTy lmukpAKrJZwrZPgqbmJTmMQE2yHYHssRKAVx2OyhIrjYKuVHDavziics6rQznL8qUOp9 /f+C/EIoxLa6VuGiAmQ2VAiLYhe7Tnjlbxg6lDLhsQEVi1+gwHESMzkmzAsXeiFR9gfK sl/US78xneXLLcW228ebSqnfn2xAp74YH4duNxcrlEZTjxpHkrobi17txGY/fuNu2fnI zqWI8fzh9yt5fLHxySQQh1cqtEncwqhOus+cTJZheEyAlm4THu60Qi+XDyT8dW+1O3lH RRww== X-Gm-Message-State: APjAAAV/DPb5z3hrp2VL/m+0xUTSIqLB76WYESkVaoGgMm9Ywu82u5oh gLpOaymeYQ/wW8ImCDF/PqOD9fO4d75yAwnZ X-Google-Smtp-Source: APXvYqzXhknzPhp8ywA8IJFv6X8bS3qEb+pGQJo6CDssSNJBkI8XUGFWLMs249ByEsdnkPkZUi5H4YIv/jBLv21t X-Received: by 2002:a65:44c8:: with SMTP id g8mr27400341pgs.443.1562028710037; Mon, 01 Jul 2019 17:51:50 -0700 (PDT) Date: Mon, 1 Jul 2019 17:51:22 -0700 Message-Id: <20190702005122.41036-1-henryburns@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH v2] mm/z3fold.c: Lock z3fold page before __SetPageMovable() From: Henry Burns To: Vitaly Wool , Andrew Morton Cc: Vitaly Vul , Mike Rapoport , Xidong Wang , Shakeel Butt , Jonathan Adams , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Henry Burns Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org __SetPageMovable() expects it's page to be locked, but z3fold.c doesn't lock the page. Following zsmalloc.c's example we call trylock_page() and unlock_page(). Also makes z3fold_page_migrate() assert that newpage is passed in locked, as documentation. Signed-off-by: Henry Burns Suggested-by: Vitaly Wool --- Changelog since v1: - Added an if statement around WARN_ON(trylock_page(page)) to avoid unlocking a page locked by a someone else. mm/z3fold.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/z3fold.c b/mm/z3fold.c index e174d1549734..6341435b9610 100644 --- a/mm/z3fold.c +++ b/mm/z3fold.c @@ -918,7 +918,10 @@ static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp, set_bit(PAGE_HEADLESS, &page->private); goto headless; } - __SetPageMovable(page, pool->inode->i_mapping); + if (!WARN_ON(!trylock_page(page))) { + __SetPageMovable(page, pool->inode->i_mapping); + unlock_page(page); + } z3fold_page_lock(zhdr); found: @@ -1325,6 +1328,7 @@ static int z3fold_page_migrate(struct address_space *mapping, struct page *newpa VM_BUG_ON_PAGE(!PageMovable(page), page); VM_BUG_ON_PAGE(!PageIsolated(page), page); + VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); zhdr = page_address(page); pool = zhdr_to_pool(zhdr); -- 2.22.0.410.gd8fdbe21b5-goog