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=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 8D17BC2D0A3 for ; Mon, 9 Nov 2020 17:00:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1844E20809 for ; Mon, 9 Nov 2020 17:00:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="kP5DkISn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731109AbgKIRAP (ORCPT ); Mon, 9 Nov 2020 12:00:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:58240 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730704AbgKIRAO (ORCPT ); Mon, 9 Nov 2020 12:00:14 -0500 Received: from localhost (unknown [104.132.1.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 692ED20789; Mon, 9 Nov 2020 17:00:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604941214; bh=e1fR8c3/u8ILpeETIXysn5Lg1umCymg7KmWhq+/rSak=; h=From:To:Cc:Subject:Date:From; b=kP5DkISnxV6x/qbDaYiMpCPbZTtX1cYBuTloAuAHYN0cKWH+492W5UCRq8ENlkNr3 49ktkkiX8+QvRgbRi8zIBpxEJ+NAfzdFZA9BgT6zpzeVwRyyKk7vFi+8Wq7jzk3N22 iHN7yeslNZv0kO/6KHWWyFgtWbChLvIEe7te+jdo= From: Jaegeuk Kim To: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com Cc: Jaegeuk Kim , Light Hsieh Subject: [PATCH] f2fs: avoid race condition for shinker count Date: Mon, 9 Nov 2020 09:00:12 -0800 Message-Id: <20201109170012.2129411-1-jaegeuk@kernel.org> X-Mailer: git-send-email 2.29.2.222.g5d2a92d10f8-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Light reported sometimes shinker gets nat_cnt < dirty_nat_cnt resulting in wrong do_shinker work. Basically the two counts should not happen like that. So, I suspect this race condtion where: - f2fs_try_to_free_nats __flush_nat_entry_set nat_cnt=2, dirty_nat_cnt=2 __clear_nat_cache_dirty spin_lock(nat_list_lock) list_move() spin_unlock(nat_list_lock) spin_lock(nat_list_lock) list_del() spin_unlock(nat_list_lock) nat_cnt=1, dirty_nat_cnt=2 nat_cnt=1, dirty_nat_cnt=1 Reported-by: Light Hsieh Signed-off-by: Jaegeuk Kim --- fs/f2fs/node.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index 42394de6c7eb..e8ec65e40f06 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -269,11 +269,10 @@ static void __clear_nat_cache_dirty(struct f2fs_nm_info *nm_i, { spin_lock(&nm_i->nat_list_lock); list_move_tail(&ne->list, &nm_i->nat_entries); - spin_unlock(&nm_i->nat_list_lock); - set_nat_flag(ne, IS_DIRTY, false); set->entry_cnt--; nm_i->dirty_nat_cnt--; + spin_unlock(&nm_i->nat_list_lock); } static unsigned int __gang_lookup_nat_set(struct f2fs_nm_info *nm_i, -- 2.29.2.222.g5d2a92d10f8-goog