From mboxrd@z Thu Jan  1 00:00:00 1970
From: Bart Van Assche <bart.vanassche@sandisk.com>
Subject: Re: v4.4-rc3 ext4 memory leak
Date: Fri, 4 Dec 2015 09:27:27 -0800
Message-ID: <5661CCFF.1050507@sandisk.com>
References: <5660C06B.4010003@sandisk.com> <20151204152232.GB3548@thunk.org>
Mime-Version: 1.0
Content-Type: text/plain; charset="utf-8"; format=flowed
Content-Transfer-Encoding: 7bit
Cc: Andreas Dilger <adilger.kernel@dilger.ca>,
	"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>
To: Theodore Ts'o <tytso@mit.edu>
Return-path: <linux-ext4-owner@vger.kernel.org>
Received: from mail-bn1on0066.outbound.protection.outlook.com ([157.56.110.66]:53693
	"EHLO na01-bn1-obe.outbound.protection.outlook.com"
	rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP
	id S1752606AbbLDS6h (ORCPT <rfc822;linux-ext4@vger.kernel.org>);
	Fri, 4 Dec 2015 13:58:37 -0500
In-Reply-To: <20151204152232.GB3548@thunk.org>
Sender: linux-ext4-owner@vger.kernel.org
List-ID: <linux-ext4.vger.kernel.org>

On 12/04/2015 07:22 AM, Theodore Ts'o wrote:
> On Thu, Dec 03, 2015 at 02:21:31PM -0800, Bart Van Assche wrote:
>> Hello,
>>
>> Running xfstests on top of an ext4 filesystem causes kmemleak to report the
>> following memory leak multiple times:
>>
>> unreferenced object 0xffff880408709730 (size 96):
>>    comm "fsstress", pid 35588, jiffies 4295006079 (age 11865.680s)
>>    hex dump (first 32 bytes):
>>      00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 00  ................
>>      00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>>    backtrace:
>>      [<ffffffff8151056a>] kmemleak_alloc+0x7a/0xc0
>>      [<ffffffff81165e6e>] __kmalloc+0xde/0x140
>>      [<ffffffffa022472e>] ext4_find_extent+0x26e/0x310 [ext4]
>>      [<ffffffffa0227f15>] ext4_insert_range+0x255/0x3c0 [ext4]
>>      [<ffffffffa022aca1>] ext4_fallocate+0x1f1/0x210 [ext4]
>>      [<ffffffff81175fb6>] vfs_fallocate+0x156/0x1e0
>>      [<ffffffff8117608e>] SyS_fallocate+0x4e/0x80
>>      [<ffffffff8151b617>] entry_SYSCALL_64_fastpath+0x12/0x6f
>>      [<ffffffffffffffff>] 0xffffffffffffffff
>
> Is this something new?   i..e, was this reproducible on v4.3?
>
> And can you isolate this to a specific test in xfstests?

Hello Ted,

So far I only ran xfstests against the 4.4-rc3 kernel so I do not know 
whether this also occurred with previous kernel versions.

kmemleak scans periodically for memory leaks. kmemleak started reporting 
these leaks after test generic/037 had started. So I think one of the 
first 37 tests triggered this leak.

Bart.