linux-kernel - Re: [PATCH] of: overlay: Stop leaking resources on overlay removal

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Message-ID: <90e7da9d-d40a-17f1-e627-873f58a3dce5@siemens.com>
Date:   Tue, 24 Apr 2018 19:50:27 +0200
From:   Jan Kiszka <jan.kiszka@...mens.com>
To:     Frank Rowand <frowand.list@...il.com>,
        Pantelis Antoniou <pantelis.antoniou@...sulko.com>,
        Rob Herring <robh+dt@...nel.org>,
        devicetree <devicetree@...r.kernel.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Alan Tull <atull@...nel.org>
Subject: Re: [PATCH] of: overlay: Stop leaking resources on overlay removal

On 2018-04-24 19:44, Frank Rowand wrote:
> On 04/24/18 09:19, Jan Kiszka wrote:
>> Only the overlay notifier callbacks have a chance to potentially get
>> hold of references to those two resources, but they do not store them.
>> So it is safe to stop the intentional leaking.
>>
>> See also https://lkml.org/lkml/2018/4/23/1063 and following.
>>
>> Signed-off-by: Jan Kiszka <jan.kiszka@...mens.com>
>> ---
>>
>> Ideally, we sort out any remaining worries during the 4.17-rc cycle.
>>
>>  drivers/of/overlay.c | 13 ++-----------
>>  1 file changed, 2 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
>> index b35fe88f1851..3553f1f57a62 100644
>> --- a/drivers/of/overlay.c
>> +++ b/drivers/of/overlay.c
>> @@ -671,17 +671,8 @@ static void free_overlay_changeset(struct overlay_changeset *ovcs)
>>  		of_node_put(ovcs->fragments[i].overlay);
>>  	}
>>  	kfree(ovcs->fragments);
>> -
>> -	/*
>> -	 * TODO
>> -	 *
>> -	 * would like to: kfree(ovcs->overlay_tree);
>> -	 * but can not since drivers may have pointers into this data
>> -	 *
>> -	 * would like to: kfree(ovcs->fdt);
>> -	 * but can not since drivers may have pointers into this data
>> -	 */
>> -
>> +	kfree(ovcs->overlay_tree);
>> +	kfree(ovcs->fdt);
>>  	kfree(ovcs);
>>  }
>>  
>>
> 
> Nack.  It is premature to submit this while the conversation is
> continuing in the other thread.
> 
> I'll continue the conversation in the other thread.
> 

Well, at least the strongest argument has been resolved now, the
notifier topic. Curious to learn what remains. As I noted, we should
work hard to sort out the API regression prior to the release.

Jan

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