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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 99B88C433B4 for ; Mon, 10 May 2021 09:31:04 +0000 (UTC) Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3C15361466 for ; Mon, 10 May 2021 09:31:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3C15361466 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-f2fs-devel-bounces@lists.sourceforge.net Received: from [127.0.0.1] (helo=sfs-ml-1.v29.lw.sourceforge.com) by sfs-ml-1.v29.lw.sourceforge.com with esmtp (Exim 4.90_1) (envelope-from ) id 1lg2Fi-0002Qd-EL; Mon, 10 May 2021 09:31:02 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-1.v29.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lg2Fc-0002OI-BD for linux-f2fs-devel@lists.sourceforge.net; Mon, 10 May 2021 09:30:56 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=Content-Type:Content-Transfer-Encoding:MIME-Version :References:In-Reply-To:Message-ID:Date:Subject:CC:To:From:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=cDmTzrnY4cN3Y8lMlJNeU9f2ZvTUWoh2BwKE7yBPGDs=; b=jqbso9sqoL+ZqkX/9/lIvQwc4Y O34dhIlYPeeXk7yaxw5RvDiZd2QIDBdBEBMxGgFoKviVgj+gb1LLkSEP8Gf8c95gKq8aHP6Qne+9f mQpQKwC1g/D/5gkEonh0Sb+G/9NSWVFnHLeuWNJ/YmSqCdPNhgxgiQ/m7IAUfGuAH/7U=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=Content-Type:Content-Transfer-Encoding:MIME-Version:References: In-Reply-To:Message-ID:Date:Subject:CC:To:From:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=cDmTzrnY4cN3Y8lMlJNeU9f2ZvTUWoh2BwKE7yBPGDs=; b=eOjMZW2TwXDaQqf+YTM+jqc8zd YSUBhqvGYRxIMh/3/qJwpAqJewTIUuSF9HJu/cySanSrLG7yOL2BZBOwvq5Bi9nGiolHEqqBnPhAB K+lboFKS0q79fvKmgKsRNf+Rh/2hbfSMk/rzNU1TBmOh7qDpMRM8C/xuJCmqQeteRhpw=; Received: from szxga04-in.huawei.com ([45.249.212.190]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92.3) id 1lg2FS-0007eb-Fj for linux-f2fs-devel@lists.sourceforge.net; Mon, 10 May 2021 09:30:56 +0000 Received: from DGGEMS411-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4FdwgX4FhTzqV24; Mon, 10 May 2021 17:27:20 +0800 (CST) Received: from szvp000203569.huawei.com (10.120.216.130) by DGGEMS411-HUB.china.huawei.com (10.3.19.211) with Microsoft SMTP Server id 14.3.498.0; Mon, 10 May 2021 17:30:34 +0800 From: Chao Yu To: Date: Mon, 10 May 2021 17:30:31 +0800 Message-ID: <20210510093032.35466-2-yuchao0@huawei.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210510093032.35466-1-yuchao0@huawei.com> References: <20210510093032.35466-1-yuchao0@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.120.216.130] X-CFilter-Loop: Reflected X-Headers-End: 1lg2FS-0007eb-Fj Subject: [f2fs-dev] [PATCH 2/3] f2fs: compress: fix race condition of overwrite vs truncate X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net pos_fsstress testcase complains a panic as belew: ------------[ cut here ]------------ kernel BUG at fs/f2fs/compress.c:1082! invalid opcode: 0000 [#1] SMP PTI CPU: 4 PID: 2753477 Comm: kworker/u16:2 Tainted: G OE 5.12.0-rc1-custom #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Workqueue: writeback wb_workfn (flush-252:16) RIP: 0010:prepare_compress_overwrite+0x4c0/0x760 [f2fs] Call Trace: f2fs_prepare_compress_overwrite+0x5f/0x80 [f2fs] f2fs_write_cache_pages+0x468/0x8a0 [f2fs] f2fs_write_data_pages+0x2a4/0x2f0 [f2fs] do_writepages+0x38/0xc0 __writeback_single_inode+0x44/0x2a0 writeback_sb_inodes+0x223/0x4d0 __writeback_inodes_wb+0x56/0xf0 wb_writeback+0x1dd/0x290 wb_workfn+0x309/0x500 process_one_work+0x220/0x3c0 worker_thread+0x53/0x420 kthread+0x12f/0x150 ret_from_fork+0x22/0x30 The root cause is truncate() may race with overwrite as below, so that one reference count left in page can not guarantee the page attaching in mapping tree all the time, after truncation, later find_lock_page() may return NULL pointer. - prepare_compress_overwrite - f2fs_pagecache_get_page - unlock_page - f2fs_setattr - truncate_setsize - truncate_inode_page - delete_from_page_cache - find_lock_page Fix this by avoiding referencing updated page. Fixes: 4c8ff7095bef ("f2fs: support data compression") Signed-off-by: Chao Yu --- fs/f2fs/compress.c | 35 ++++++++++++----------------------- 1 file changed, 12 insertions(+), 23 deletions(-) diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c index d5cb0ba9a0e1..340815cd0887 100644 --- a/fs/f2fs/compress.c +++ b/fs/f2fs/compress.c @@ -118,19 +118,6 @@ static void f2fs_unlock_rpages(struct compress_ctx *cc, int len) f2fs_drop_rpages(cc, len, true); } -static void f2fs_put_rpages_mapping(struct address_space *mapping, - pgoff_t start, int len) -{ - int i; - - for (i = 0; i < len; i++) { - struct page *page = find_get_page(mapping, start + i); - - put_page(page); - put_page(page); - } -} - static void f2fs_put_rpages_wbc(struct compress_ctx *cc, struct writeback_control *wbc, bool redirty, int unlock) { @@ -1040,7 +1027,7 @@ static int prepare_compress_overwrite(struct compress_ctx *cc, } if (PageUptodate(page)) - unlock_page(page); + f2fs_put_page(page, 1); else f2fs_compress_ctx_add_page(cc, page); } @@ -1050,32 +1037,34 @@ static int prepare_compress_overwrite(struct compress_ctx *cc, ret = f2fs_read_multi_pages(cc, &bio, cc->cluster_size, &last_block_in_bio, false, true); + f2fs_put_rpages(cc); f2fs_destroy_compress_ctx(cc); if (ret) - goto release_pages; + goto out; if (bio) f2fs_submit_bio(sbi, bio, DATA); ret = f2fs_init_compress_ctx(cc); if (ret) - goto release_pages; + goto out; } for (i = 0; i < cc->cluster_size; i++) { f2fs_bug_on(sbi, cc->rpages[i]); page = find_lock_page(mapping, start_idx + i); - f2fs_bug_on(sbi, !page); + if (!page) { + /* page can be truncated */ + goto release_and_retry; + } f2fs_wait_on_page_writeback(page, DATA, true, true); - f2fs_compress_ctx_add_page(cc, page); - f2fs_put_page(page, 0); if (!PageUptodate(page)) { +release_and_retry: + f2fs_put_rpages(cc); f2fs_unlock_rpages(cc, i + 1); - f2fs_put_rpages_mapping(mapping, start_idx, - cc->cluster_size); f2fs_destroy_compress_ctx(cc); goto retry; } @@ -1108,10 +1097,10 @@ static int prepare_compress_overwrite(struct compress_ctx *cc, } unlock_pages: + f2fs_put_rpages(cc); f2fs_unlock_rpages(cc, i); -release_pages: - f2fs_put_rpages_mapping(mapping, start_idx, i); f2fs_destroy_compress_ctx(cc); +out: return ret; } -- 2.29.2 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel