Re: [PATCH] net: mdiobus: Fix memory leak in __mdiobus_register

From: Pavel Skripkin <paskripkin@gmail.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Yanfei Xu <yanfei.xu@windriver.com>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	andrew@lunn.ch, hkallweit1@gmail.com, linux@armlinux.org.uk,
	davem@davemloft.net, kuba@kernel.org, p.zabel@pengutronix.de,
	syzbot+398e7dc692ddbbb4cfec@syzkaller.appspotmail.com,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	Dongliang Mu <mudongliangabcd@gmail.com>
Subject: Re: [PATCH] net: mdiobus: Fix memory leak in __mdiobus_register
Date: Tue, 28 Sep 2021 14:04:48 +0300	[thread overview]
Message-ID: <0ff35e57-978a-ed79-d401-cbe3f86835af@gmail.com> (raw)
In-Reply-To: <20210928105522.GK2083@kadam>

On 9/28/21 13:55, Dan Carpenter wrote:
> On Tue, Sep 28, 2021 at 01:46:56PM +0300, Pavel Skripkin wrote:
>> On 9/28/21 13:39, Dan Carpenter wrote:
>> > No, the syzbot link was correct.
>> > 
>> 
>> Link is correct, but Yanfei's patch does not fix this bug. Syzbot reported
>> leak, that you described below, not the Yanfei one.
>> 
> 
> I promise you that Yanfei's link was correct.  That bug was in
> __devm_mdiobus_register().  It's a totally separate issue.
> 

I must be missing something, or we are talking about different links :)

Let me explain why I think, that Yanfei's patch cannot fix leak reported 
by syzkaller [1] (I hope, we are talking about this link)

Yanfei has changed this code part:

	err = device_register(&bus->dev);
	if (err) {
(*)		pr_err("mii_bus %s failed to register\n", bus->id);
		return -EINVAL;
	}

So, if executing gets into this branch we should see error message (*), 
right? There is no such message into log file on bug report page [1], so 
how is it possible?

[1] 
https://syzkaller.appspot.com/bug?id=fa99459691911a0369622248e0f4e3285fcedd97

With regards,
Pavel Skripkin