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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61A15C00140 for ; Fri, 12 Aug 2022 13:41:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239026AbiHLNlz (ORCPT ); Fri, 12 Aug 2022 09:41:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236979AbiHLNlu (ORCPT ); Fri, 12 Aug 2022 09:41:50 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E59349F764 for ; Fri, 12 Aug 2022 06:41:49 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 7B909617E8 for ; Fri, 12 Aug 2022 13:41:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5EFE9C433C1; Fri, 12 Aug 2022 13:41:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660311708; bh=F2D0qcEq733snV+Eq573OoED0RLO7MPIXbjPMiBF1dI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=H0Qu5cNm73nEFiVjiJNZzexPGRO0s4ZMrv4rm9rZKD3DcFvrAD1CFTlxvkGe85GPV rhMW/v8p1zWX5AL6rjro9yn2y4R+k/7cr0QySEPCDqmLpEWY3UeTeYsTNjEzS9DeUk HvZ/cyEUgyB7v0YAGBdIBHU9KXLkP8cvUJMsZwn0= Date: Fri, 12 Aug 2022 15:41:46 +0200 From: Greg Kroah-Hartman To: Dongliang Mu Cc: Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Todd Kjos , Martijn Coenen , Joel Fernandes , Christian Brauner , Carlos Llamas , Suren Baghdasaryan , Kees Cook , Dongliang Mu , syzkaller , linux-kernel@vger.kernel.org Subject: Re: [PATCH] drivers: binderfs: fix memory leak in binderfs_fill_super Message-ID: References: <20220812132124.2053673-1-dzm91@hust.edu.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220812132124.2053673-1-dzm91@hust.edu.cn> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 12, 2022 at 09:21:24PM +0800, Dongliang Mu wrote: > From: Dongliang Mu > > In binderfs_fill_super, if s_root is not successfully initialized by > d_make_root, the previous allocated s_sb_info will not be freed since > generic_shutdown_super first checks if sb->s_root and then does > put_super operation. The put_super operation calls binderfs_put_super > to deallocate s_sb_info and put ipc_ns. This will lead to memory leak > in binderfs_fill_super. > > Fix this by invoking binderfs_put_super at error sites before s_root > is successfully initialized. > > Fixes: 095cf502b31e ("binderfs: port to new mount api") > Reported-by: syzkaller Where is the specific syzkaller link for this report? It would be good to reference it so it can be properly checked. Also, how did you test this change? > Signed-off-by: Dongliang Mu > --- > drivers/android/binderfs.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c > index 588d753a7a19..20f5bc77495f 100644 > --- a/drivers/android/binderfs.c > +++ b/drivers/android/binderfs.c > @@ -710,8 +710,10 @@ static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) > info->mount_opts.stats_mode = ctx->stats_mode; > > inode = new_inode(sb); > - if (!inode) > + if (!inode) { > + binderfs_put_super(sb); > return -ENOMEM; > + } > > inode->i_ino = FIRST_INODE; > inode->i_fop = &simple_dir_operations; > @@ -721,8 +723,10 @@ static int binderfs_fill_super(struct super_block *sb, struct fs_context *fc) > set_nlink(inode, 2); > > sb->s_root = d_make_root(inode); > - if (!sb->s_root) > + if (!sb->s_root) { > + binderfs_put_super(sb); > return -ENOMEM; > + } How did you test this change to verify that you are not now just leaking memory? It looks to me like you just changed one problem for another one :( Please always be very very careful when making these types of changes, and verify and test that they are correct. thanks, greg k-h