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=-9.7 required=3.0 tests=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 BA013C432C0 for ; Mon, 18 Nov 2019 03:27:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 927A8206D3 for ; Mon, 18 Nov 2019 03:27:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726317AbfKRD1w (ORCPT ); Sun, 17 Nov 2019 22:27:52 -0500 Received: from szxga05-in.huawei.com ([45.249.212.191]:6245 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726266AbfKRD1w (ORCPT ); Sun, 17 Nov 2019 22:27:52 -0500 Received: from DGGEMS409-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id CF5E05946BBEFAA9547A; Mon, 18 Nov 2019 11:27:50 +0800 (CST) Received: from localhost.localdomain.localdomain (10.175.113.25) by DGGEMS409-HUB.china.huawei.com (10.3.19.209) with Microsoft SMTP Server id 14.3.439.0; Mon, 18 Nov 2019 11:27:40 +0800 From: zhong jiang To: , , , CC: , Subject: [PATCH 4.9] memfd: Use radix_tree_deref_slot_protected to avoid the warning. Date: Mon, 18 Nov 2019 11:26:10 +0800 Message-ID: <20191118032610.182862-4-zhongjiang@huawei.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191118032610.182862-1-zhongjiang@huawei.com> References: <20191118032610.182862-1-zhongjiang@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.113.25] X-CFilter-Loop: Reflected Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The commit 3ce6b467b9b2 ("memfd: Fix locking when tagging pins") introduces the following warning messages. *WARNING: suspicious RCU usage in memfd_wait_for_pins* It is because we still use radix_tree_deref_slot without read_rcu_lock. We should use radix_tree_deref_slot_protected instead in the case. Cc: stable@vger.kernel.org Fixes: 3ce6b467b9b2 ("memfd: Fix locking when tagging pins") Signed-off-by: zhong jiang --- mm/shmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/shmem.c b/mm/shmem.c index ac8a5fedc245..6266a7d1ba00 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2464,7 +2464,7 @@ static void shmem_tag_pins(struct address_space *mapping) spin_lock_irq(&mapping->tree_lock); radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { - page = radix_tree_deref_slot(slot); + page = radix_tree_deref_slot_protected(slot, &mapping->tree_lock); if (!page || radix_tree_exception(page)) { if (radix_tree_deref_retry(page)) { slot = radix_tree_iter_retry(&iter); -- 2.20.1