From nobody Wed Sep 3 06:46:55 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9716EFA3740 for ; Mon, 24 Oct 2022 12:28:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233804AbiJXM2S (ORCPT ); Mon, 24 Oct 2022 08:28:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60586 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230499AbiJXM1I (ORCPT ); Mon, 24 Oct 2022 08:27:08 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 102C37B1E0; Mon, 24 Oct 2022 05:01:32 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B82BBB811D7; Mon, 24 Oct 2022 11:56:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 180B8C433C1; Mon, 24 Oct 2022 11:56:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666612595; bh=4/0gbWRoGgXhcpCItadg29FCqoOIDIWdJPHkOeinRzA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NCzedvpQOFX7vgVeWYxiERiZXxGvG2QJWpJV9E8NtnmZqgYjOiXbmjRF85mjxxIE0 G8bB5Ntca/w00xPVJ9g9UHNzoNe2X0qDo1rXLJW5WjvSTrd38Ln4tFHpf7ImPOrCfO 9ts6bXV52/UfBgy1S/Xs0Pgpciu2OgzgPGOE5pwA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ryusuke Konishi , syzbot+7381dc4ad60658ca4c05@syzkaller.appspotmail.com, Andrew Morton Subject: [PATCH 4.19 019/229] nilfs2: fix leak of nilfs_root in case of writer thread creation failure Date: Mon, 24 Oct 2022 13:28:58 +0200 Message-Id: <20221024112959.757408197@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221024112959.085534368@linuxfoundation.org> References: <20221024112959.085534368@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Ryusuke Konishi commit d0d51a97063db4704a5ef6bc978dddab1636a306 upstream. If nilfs_attach_log_writer() failed to create a log writer thread, it frees a data structure of the log writer without any cleanup. After commit e912a5b66837 ("nilfs2: use root object to get ifile"), this causes a leak of struct nilfs_root, which started to leak an ifile metadata inode and a kobject on that struct. In addition, if the kernel is booted with panic_on_warn, the above ifile metadata inode leak will cause the following panic when the nilfs2 kernel module is removed: kmem_cache_destroy nilfs2_inode_cache: Slab cache still has objects when called from nilfs_destroy_cachep+0x16/0x3a [nilfs2] WARNING: CPU: 8 PID: 1464 at mm/slab_common.c:494 kmem_cache_destroy+0x13= 8/0x140 ... RIP: 0010:kmem_cache_destroy+0x138/0x140 Code: 00 20 00 00 e8 a9 55 d8 ff e9 76 ff ff ff 48 8b 53 60 48 c7 c6 20 7= 0 65 86 48 c7 c7 d8 69 9c 86 48 8b 4c 24 28 e8 ef 71 c7 00 <0f> 0b e9 53 ff= ff ff c3 48 81 ff ff 0f 00 00 77 03 31 c0 c3 53 48 ... Call Trace: ? nilfs_palloc_freev.cold.24+0x58/0x58 [nilfs2] nilfs_destroy_cachep+0x16/0x3a [nilfs2] exit_nilfs_fs+0xa/0x1b [nilfs2] __x64_sys_delete_module+0x1d9/0x3a0 ? __sanitizer_cov_trace_pc+0x1a/0x50 ? syscall_trace_enter.isra.19+0x119/0x190 do_syscall_64+0x34/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd ... Kernel panic - not syncing: panic_on_warn set ... This patch fixes these issues by calling nilfs_detach_log_writer() cleanup function if spawning the log writer thread fails. Link: https://lkml.kernel.org/r/20221007085226.57667-1-konishi.ryusuke@gmai= l.com Fixes: e912a5b66837 ("nilfs2: use root object to get ifile") Signed-off-by: Ryusuke Konishi Reported-by: syzbot+7381dc4ad60658ca4c05@syzkaller.appspotmail.com Tested-by: Ryusuke Konishi Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- fs/nilfs2/segment.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/fs/nilfs2/segment.c +++ b/fs/nilfs2/segment.c @@ -2786,10 +2786,9 @@ int nilfs_attach_log_writer(struct super inode_attach_wb(nilfs->ns_bdev->bd_inode, NULL); =20 err =3D nilfs_segctor_start_thread(nilfs->ns_writer); - if (err) { - kfree(nilfs->ns_writer); - nilfs->ns_writer =3D NULL; - } + if (unlikely(err)) + nilfs_detach_log_writer(sb); + return err; }