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=-13.7 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 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 2EC9AC433ED for ; Tue, 13 Apr 2021 01:36:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E96CA6128A for ; Tue, 13 Apr 2021 01:36:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240654AbhDMBg3 (ORCPT ); Mon, 12 Apr 2021 21:36:29 -0400 Received: from mga14.intel.com ([192.55.52.115]:31488 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239217AbhDMBg2 (ORCPT ); Mon, 12 Apr 2021 21:36:28 -0400 IronPort-SDR: Ks0mNFRqGQZmpFyxEOl2Z5y1JGtX5HLC+GQEeVxxYk/QpbdjfqDHx6kK6o7lq0iUEFNy3WffUi rSRjbpmeacuQ== X-IronPort-AV: E=McAfee;i="6200,9189,9952"; a="193875059" X-IronPort-AV: E=Sophos;i="5.82,216,1613462400"; d="scan'208";a="193875059" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Apr 2021 18:36:08 -0700 IronPort-SDR: zRlTi4pzNrHKsmZ1fcfAtAzWVA3jCcJG8g9hFVnAJVpg7onB/ZJS3Ep7RWTCBa6g8uZXCUGAey ojf9Jh8O6dpA== X-IronPort-AV: E=Sophos;i="5.82,216,1613462400"; d="scan'208";a="460397719" Received: from yhuang6-desk1.sh.intel.com (HELO yhuang6-desk1.ccr.corp.intel.com) ([10.239.13.1]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Apr 2021 18:36:04 -0700 From: "Huang, Ying" To: Miaohe Lin Cc: , , , , , , , , , , , , Subject: Re: [PATCH 5/5] mm/swap_state: fix swap_cluster_readahead() race with swapoff References: <20210408130820.48233-1-linmiaohe@huawei.com> <20210408130820.48233-6-linmiaohe@huawei.com> Date: Tue, 13 Apr 2021 09:36:02 +0800 In-Reply-To: <20210408130820.48233-6-linmiaohe@huawei.com> (Miaohe Lin's message of "Thu, 8 Apr 2021 09:08:20 -0400") Message-ID: <87eeffufst.fsf@yhuang6-desk1.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Miaohe Lin writes: > swap_cluster_readahead() could race with swapoff and might dereference > si->swap_file after it's released by swapoff. Close this race window by > using get/put_swap_device() pair. I think we should fix the callers instead to reduce the overhead. Now, do_swap_page() has been fixed. We need to fix shmem_swapin(). Best Regards, Huang, Ying > Signed-off-by: Miaohe Lin > --- > mm/swap_state.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/mm/swap_state.c b/mm/swap_state.c > index 3bf0d0c297bc..eba6b0cf6cf9 100644 > --- a/mm/swap_state.c > +++ b/mm/swap_state.c > @@ -626,12 +626,17 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, > unsigned long offset = entry_offset; > unsigned long start_offset, end_offset; > unsigned long mask; > - struct swap_info_struct *si = swp_swap_info(entry); > + struct swap_info_struct *si; > struct blk_plug plug; > bool do_poll = true, page_allocated; > struct vm_area_struct *vma = vmf->vma; > unsigned long addr = vmf->address; > > + si = get_swap_device(entry); > + /* In case we raced with swapoff. */ > + if (!si) > + return NULL; > + > mask = swapin_nr_pages(offset) - 1; > if (!mask) > goto skip; > @@ -673,7 +678,9 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, > > lru_add_drain(); /* Push any new pages onto the LRU now */ > skip: > - return read_swap_cache_async(entry, gfp_mask, vma, addr, do_poll); > + page = read_swap_cache_async(entry, gfp_mask, vma, addr, do_poll); > + put_swap_device(si); > + return page; > } > > int init_swap_address_space(unsigned int type, unsigned long nr_pages) 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=-13.7 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 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 264E8C433B4 for ; Tue, 13 Apr 2021 01:36:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 89A546124C for ; 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Tue, 13 Apr 2021 01:36:11 +0000 (UTC) X-FDA: 78025628142.24.B508648 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by imf10.hostedemail.com (Postfix) with ESMTP id D5B2E40002D0 for ; Tue, 13 Apr 2021 01:36:05 +0000 (UTC) IronPort-SDR: DdKsGMZN33BKnfqM1zhWbAeaUQhj5UA4P2YVCSz3bKk483l1C2kniI3VnEXTS06iYYjzF8AIaI koLyijMkTlsw== X-IronPort-AV: E=McAfee;i="6200,9189,9952"; a="192185675" X-IronPort-AV: E=Sophos;i="5.82,216,1613462400"; d="scan'208";a="192185675" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Apr 2021 18:36:09 -0700 IronPort-SDR: zRlTi4pzNrHKsmZ1fcfAtAzWVA3jCcJG8g9hFVnAJVpg7onB/ZJS3Ep7RWTCBa6g8uZXCUGAey ojf9Jh8O6dpA== X-IronPort-AV: E=Sophos;i="5.82,216,1613462400"; d="scan'208";a="460397719" Received: from yhuang6-desk1.sh.intel.com (HELO yhuang6-desk1.ccr.corp.intel.com) ([10.239.13.1]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Apr 2021 18:36:04 -0700 From: "Huang, Ying" To: Miaohe Lin Cc: , , , , , , , , , , , , Subject: Re: [PATCH 5/5] mm/swap_state: fix swap_cluster_readahead() race with swapoff References: <20210408130820.48233-1-linmiaohe@huawei.com> <20210408130820.48233-6-linmiaohe@huawei.com> Date: Tue, 13 Apr 2021 09:36:02 +0800 In-Reply-To: <20210408130820.48233-6-linmiaohe@huawei.com> (Miaohe Lin's message of "Thu, 8 Apr 2021 09:08:20 -0400") Message-ID: <87eeffufst.fsf@yhuang6-desk1.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: D5B2E40002D0 X-Stat-Signature: d4pkegk3xr743a53ctb3ihekgi79w797 Received-SPF: none (intel.com>: No applicable sender policy available) receiver=imf10; identity=mailfrom; envelope-from=""; helo=mga04.intel.com; client-ip=192.55.52.120 X-HE-DKIM-Result: none/none X-HE-Tag: 1618277765-503975 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Miaohe Lin writes: > swap_cluster_readahead() could race with swapoff and might dereference > si->swap_file after it's released by swapoff. Close this race window by > using get/put_swap_device() pair. I think we should fix the callers instead to reduce the overhead. Now, do_swap_page() has been fixed. We need to fix shmem_swapin(). Best Regards, Huang, Ying > Signed-off-by: Miaohe Lin > --- > mm/swap_state.c | 11 +++++++++-- > 1 file changed, 9 insertions(+), 2 deletions(-) > > diff --git a/mm/swap_state.c b/mm/swap_state.c > index 3bf0d0c297bc..eba6b0cf6cf9 100644 > --- a/mm/swap_state.c > +++ b/mm/swap_state.c > @@ -626,12 +626,17 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, > unsigned long offset = entry_offset; > unsigned long start_offset, end_offset; > unsigned long mask; > - struct swap_info_struct *si = swp_swap_info(entry); > + struct swap_info_struct *si; > struct blk_plug plug; > bool do_poll = true, page_allocated; > struct vm_area_struct *vma = vmf->vma; > unsigned long addr = vmf->address; > > + si = get_swap_device(entry); > + /* In case we raced with swapoff. */ > + if (!si) > + return NULL; > + > mask = swapin_nr_pages(offset) - 1; > if (!mask) > goto skip; > @@ -673,7 +678,9 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, > > lru_add_drain(); /* Push any new pages onto the LRU now */ > skip: > - return read_swap_cache_async(entry, gfp_mask, vma, addr, do_poll); > + page = read_swap_cache_async(entry, gfp_mask, vma, addr, do_poll); > + put_swap_device(si); > + return page; > } > > int init_swap_address_space(unsigned int type, unsigned long nr_pages)