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Subject: Re: WARNING: kobject bug in br_add_if
From:   Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
To:     Hangbin Liu <liuhangbin@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>
Cc:     syzbot <syzbot+de73361ee4971b6e6f75@syzkaller.appspotmail.com>,
        bridge@lists.linux-foundation.org,
        David Miller <davem@davemloft.net>,
        LKML <linux-kernel@vger.kernel.org>,
        netdev <netdev@vger.kernel.org>,
        stephen hemminger <stephen@networkplumber.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Message-ID: <90eb7466-35de-f1cf-c186-dc367ad5257f@cumulusnetworks.com>
Date:   Thu, 26 Apr 2018 14:51:21 +0300
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On 26/04/18 14:49, Nikolay Aleksandrov wrote:
> On 26/04/18 13:37, Hangbin Liu wrote:
>> On Thu, Apr 26, 2018 at 10:04:16AM +0200, Dmitry Vyukov wrote:
>>> On Thu, Apr 26, 2018 at 8:13 AM, Hangbin Liu <liuhangbin@gmail.com> wrote:
>>>> On Wed, Apr 11, 2018 at 05:18:23PM +0200, Dmitry Vyukov wrote:
>>>>> On Wed, Apr 11, 2018 at 5:15 PM, syzbot
>>>>> <syzbot+de73361ee4971b6e6f75@syzkaller.appspotmail.com> wrote:
>>>>>> kobject_add_internal failed for brport (error: -12 parent: bond0)
> [snip]
>>
>> Re-checked the error. This is a -ENOMEM. So normally we could ignore it.
>>
>> But on the other hand, although we could find out the slave iface's
>> master in netdev_master_upper_dev_link(). It already go much further
>> and allocate some resource and change iface state. e.g.
>>
>> [54273.968516] br0: port 1(em1) entered blocking state
>> [54273.973979] br0: port 1(em1) entered disabled state
>>
>> So I think we'd better return as early as possible. I will post a fix
>> for this.
>>
>> Thanks
>> Hangbin
> 
> If I'm not mistaken the bridge allocated resources for the port are
> cleaned on kobject_init_and_add() error return. Or are you talking
> about some other resources ?
> 

Ah, my bad - you weren't talking about resource freeing.
Nevermind my comment.