linux-kernel - Re: kmemleak report after 9082e87bfbf8 ("block: remove struct bio

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Message-ID: <5756482D.2040505@lwfinger.net>
Date:	Mon, 6 Jun 2016 23:06:05 -0500
From:	Larry Finger <Larry.Finger@...inger.net>
To:	Catalin Marinas <catalin.marinas@....com>,
	Christoph Hellwig <hch@....de>
Cc:	linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
	Jens Axboe <axboe@...com>, bart.vanassche@...disk.com,
	drysdale@...gle.com
Subject: Re: kmemleak report after 9082e87bfbf8 ("block: remove struct
 bio_batch")

On 06/06/2016 11:12 AM, Catalin Marinas wrote:
> On Mon, Jun 06, 2016 at 04:13:34PM +0200, Christoph Hellwig wrote:
>> I've got a few reports of this over the weekend, but it still doesn't
>> make much sense to me.
>>
>> Could it be that kmemleak can't deal with the bio_batch logic?  I've
>> tried to look at the various bio and biovec number entries in
>> /proc/slabinfo, and while they keep changing a bit during the
>> system runtime there doesn't seem to be a persistent increase
>> even after lots of mkfs calls.
>
> I think the reported leaks settle after about 10-20min (2-3 kmemleak
> periodic scans), so checking /proc/slabinfo may not be sufficient if
> the leak is not growing. The leaks also do not seem to disappear,
> otherwise kmemleak would no longer report them (e.g. after kfree, even
> if they had been previously reported).

The leak is definitely not related to mkfs. At the moment, my system has been up 
about 26 hours, and has generated 162 of these leaks without ever doing a single 
mkfs. In addition, the box say idle for almost 12 of those hours.

Larry