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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 7B3F8C433ED for ; Thu, 8 Apr 2021 13:09:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 547476113C for ; Thu, 8 Apr 2021 13:09:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231673AbhDHNJh (ORCPT ); Thu, 8 Apr 2021 09:09:37 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:16418 "EHLO szxga06-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231610AbhDHNJb (ORCPT ); Thu, 8 Apr 2021 09:09:31 -0400 Received: from DGGEMS413-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4FGM4L1YkKzkjgH; Thu, 8 Apr 2021 21:07:30 +0800 (CST) Received: from huawei.com (10.175.104.175) by DGGEMS413-HUB.china.huawei.com (10.3.19.213) with Microsoft SMTP Server id 14.3.498.0; Thu, 8 Apr 2021 21:09:09 +0800 From: Miaohe Lin To: CC: , , , , , , , , , , , , , Subject: [PATCH 3/5] mm/swap_state: fix get_shadow_from_swap_cache() race with swapoff Date: Thu, 8 Apr 2021 09:08:18 -0400 Message-ID: <20210408130820.48233-4-linmiaohe@huawei.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20210408130820.48233-1-linmiaohe@huawei.com> References: <20210408130820.48233-1-linmiaohe@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.104.175] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The function get_shadow_from_swap_cache() can race with swapoff, though it's only called by do_swap_page() now. Fixes: aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU") Signed-off-by: Miaohe Lin --- mm/swap_state.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/mm/swap_state.c b/mm/swap_state.c index 272ea2108c9d..709c260d644a 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -83,11 +83,14 @@ void show_swap_cache_info(void) void *get_shadow_from_swap_cache(swp_entry_t entry) { - struct address_space *address_space = swap_address_space(entry); - pgoff_t idx = swp_offset(entry); + struct swap_info_struct *si; struct page *page; - page = xa_load(&address_space->i_pages, idx); + si = get_swap_device(entry); + if (!si) + return NULL; + page = xa_load(&swap_address_space(entry)->i_pages, swp_offset(entry)); + put_swap_device(si); if (xa_is_value(page)) return page; return NULL; -- 2.19.1