Subject: Re: [PATCH] kobject: fix suppressing modalias in uevents delivered
 over netlink
To: Eric Dumazet <edumazet@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Eric Dumazet <eric.dumazet@gmail.com>,
        Tariq Toukan <tariqt@mellanox.com>,
        "David S . Miller" <davem@davemloft.net>,
        Komali Katari <komali@chelsio.com>,
        "Luis R. Rodriguez" <mcgrof@kernel.org>,
        Casey Leedom <leedom@chelsio.com>, LKML <linux-kernel@vger.kernel.org>
References: <20171213232122.5ztmwume5kylh4mz@dtor-ws>
 <20171219084819.GB15010@kroah.com>
 <CANn89i+OGcnsR5pFiV050a-KtXE=O6zg7+h2RjJQbs82SFL0UQ@mail.gmail.com>
From: Tariq Toukan <tariqt@mellanox.com>
Message-ID: <4244cb34-a90a-1c50-20e8-f8b610bb7eeb@mellanox.com>
Date: Tue, 19 Dec 2017 17:41:01 +0200
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101
 Thunderbird/52.5.0
MIME-Version: 1.0
In-Reply-To: <CANn89i+OGcnsR5pFiV050a-KtXE=O6zg7+h2RjJQbs82SFL0UQ@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
SpamDiagnosticOutput: 1:99
SpamDiagnosticMetadata: NSPM
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Dec 2017 15:41:07.8103
 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: 2ab204dc-dd61-40b2-b2e4-08d546f6ecc5
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: a652971c-7d2e-4d9b-a6a4-d149256f461b
X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1PR05MB1149
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 1661
Lines: 41


On 19/12/2017 11:12 AM, Eric Dumazet wrote:
> On Tue, Dec 19, 2017 at 12:48 AM, Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
>> On Wed, Dec 13, 2017 at 03:21:22PM -0800, Dmitry Torokhov wrote:
>>> The commit 4a336a23d619 ("kobject: copy env blob in one go") optimized
>>> constructing uevent data for delivery over netlink by using the raw
>>> environment buffer, instead of reconstructing it from individual
>>> environment pointers. Unfortunately in doing so it broke suppressing
>>> MODALIAS attribute for KOBJ_UNBIND events, as the code that suppressed this
>>> attribute only adjusted the environment pointers, but left the buffer
>>> itself alone. Let's fix it by making sure the offending attribute is
>>> obliterated form the buffer as well.
>>>
>>> Reported-by: Tariq Toukan <tariqt@mellanox.com>
>>> Reported-by: Casey Leedom <leedom@chelsio.com>
>>> Fixes: 4a336a23d619 ("kobject: copy env blob in one go")
>>> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>>> ---
>>>   lib/kobject_uevent.c | 16 ++++++++++++----
>>>   1 file changed, 12 insertions(+), 4 deletions(-)
>>
>> Ok, I'm lost here, is this patch still needed for 4.15-final?
>>

Yes this is needed, it solves the issue I reported.
Thanks.

>> And am I supposed to be taking it through my tree as the offending patch
>> didn't come from me?  :)
> 
> Sorry for that, I sent a patch series (
> 8ca712c373a462cfa1b62272870b6c2c74aa83f9 )
> that was mostly network related stuff (dealing with skbs and all rtnl batching),
> and sent it to David before Dmitry patch was visible in David tree.
> 
> Yes, we believe fix in zap_modalias_env() is needed.
> 
> Thanks.
>