Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753841AbcDTF4F (ORCPT ); Wed, 20 Apr 2016 01:56:05 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:37821 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751279AbcDTF4D (ORCPT ); Wed, 20 Apr 2016 01:56:03 -0400 Date: Wed, 20 Apr 2016 14:55:58 +0900 From: Greg KH To: Nikhilesh Reddy Cc: linux-fsdevel , Al Viro , Linux Kernel Mailing List Subject: Re: Umount failing due to a file leak on 3.18 Android Message-ID: <20160420055558.GB6031@kroah.com> References: <5716DAC3.4070404@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5716DAC3.4070404@codeaurora.org> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1287 Lines: 31 On Tue, Apr 19, 2016 at 06:26:27PM -0700, Nikhilesh Reddy wrote: > Hi > > I am looking into a bug that results in umount failures ( since there is a mount ref from the leaked file that is never freed on the mount ) > > The issue seems to be a result of the following callstack > > 39.958104: <6> Call trace: > 39.958108: <2> [] fput+0x1e0/0x1f8 > 39.958113: <2> [] filp_close+0xa0/0xb8 > 39.958119: <2> [] put_files_struct+0x88/0xf0 > 39.958123: <2> [] binder_deferred_func+0x6a8/0x704 > 39.958129: <2> [] process_one_work+0x238/0x3f0 > 39.958133: <2> [] worker_thread+0x2f8/0x418 > > What seems to occur is that once in a while a file ( say a.txt) is fput in the above stack > right as the task is being killed > > And then we see that the fput schedules a delayed_fput_work on this file > > But when the function delayed_fput() is actually run : > the file that was put i.e this a.txt is not in the delayed_fput_list > > Any chance you can help me get to the bottom of this leak? > I dont understand why the delayed_fput_list is missing the file. 3.18 is very old, can you duplicate this on 4.5 or newer? thanks, greg k-h