From: "Hans Verkuil (hansverk)" <hansverk@cisco.com>
To: Wen Yang <yellowriver2010@hotmail.com>,
Hans Verkuil <hans.verkuil@cisco.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Linux Media Mailing List <linux-media@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/4] media: cec-notifier: fix possible object reference leak
Date: Mon, 11 Feb 2019 10:57:31 +0000 [thread overview]
Message-ID: <6b7fc837599e4069b876b32473b31746@XCH-ALN-012.cisco.com> (raw)
In-Reply-To: 3ed515b78a404ec4a22b5f69ed9d6e28@XCH-ALN-012.cisco.com
On 11/02/2019 11:38, Hans Verkuil (hansverk) wrote:
> On 09/02/2019 03:48, Wen Yang wrote:
>> put_device() should be called in cec_notifier_release(),
>> since the dev is being passed down to cec_notifier_get_conn(),
>> which holds reference. On cec_notifier destruction, it
>> should drop the reference to the device.
>>
>> Fixes: 6917a7b77413 ("[media] media: add CEC notifier support")
>> Signed-off-by: Wen Yang <yellowriver2010@hotmail.com>
>> ---
>> drivers/media/cec/cec-notifier.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/media/cec/cec-notifier.c b/drivers/media/cec/cec-notifier.c
>> index dd2078b..621d4ae 100644
>> --- a/drivers/media/cec/cec-notifier.c
>> +++ b/drivers/media/cec/cec-notifier.c
>> @@ -66,6 +66,7 @@ static void cec_notifier_release(struct kref *kref)
>> container_of(kref, struct cec_notifier, kref);
>>
>> list_del(&n->head);
>> + put_device(n->dev);
>> kfree(n->conn);
>> kfree(n);
>> }
>>
>
> Sorry, no. The dev pointer is just a search key that the notifier code looks
> for. It is not the notifier's responsibility to take a reference, that would
> be the responsibility of the hdmi and cec drivers.
Correction: the cec driver should never take a reference of the hdmi device.
It never accesses the HDMI device, it only needs the HDMI device pointer as
a key in the notifier list.
The real problem is that several CEC drivers take a reference of the HDMI device
and never release it. So those drivers need to be fixed.
Regards,
Hans
>
> If you can demonstrate that there is an object reference leak, then please
> provide the details: it is likely a bug elsewhere and not in the notifier
> code.
>
> BTW, your patch series didn't arrive on the linux-media mailinglist for
> some reason.
>
> Regards,
>
> Hans
>
next prev parent reply other threads:[~2019-02-11 10:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <HK0PR02MB363461179B3A702DB9CAEC55B26A0@HK0PR02MB3634.apcprd02.prod.outlook.com>
2019-02-11 10:38 ` [PATCH 1/4] media: cec-notifier: fix possible object reference leak Hans Verkuil (hansverk)
2019-02-11 10:57 ` Hans Verkuil (hansverk) [this message]
[not found] ` <HK0PR02MB3634D1937109CD28ECBF1654B2650@HK0PR02MB3634.apcprd02.prod.outlook.com>
2019-02-12 13:39 ` 答复: " Hans Verkuil (hansverk)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=6b7fc837599e4069b876b32473b31746@XCH-ALN-012.cisco.com \
--to=hansverk@cisco.com \
--cc=hans.verkuil@cisco.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=mchehab@kernel.org \
--cc=yellowriver2010@hotmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).