linux-kernel - Re: [PATCH] kobject: fix suppressing modalias in uevents delivered over netlink

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Message-ID: <4244cb34-a90a-1c50-20e8-f8b610bb7eeb@mellanox.com>
Date:   Tue, 19 Dec 2017 17:41:01 +0200
From:   Tariq Toukan <tariqt@...lanox.com>
To:     Eric Dumazet <edumazet@...gle.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Eric Dumazet <eric.dumazet@...il.com>,
        Tariq Toukan <tariqt@...lanox.com>,
        "David S . Miller" <davem@...emloft.net>,
        Komali Katari <komali@...lsio.com>,
        "Luis R. Rodriguez" <mcgrof@...nel.org>,
        Casey Leedom <leedom@...lsio.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] kobject: fix suppressing modalias in uevents delivered
 over netlink



On 19/12/2017 11:12 AM, Eric Dumazet wrote:
> On Tue, Dec 19, 2017 at 12:48 AM, Greg Kroah-Hartman
> <gregkh@...uxfoundation.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@...lanox.com>
>>> Reported-by: Casey Leedom <leedom@...lsio.com>
>>> Fixes: 4a336a23d619 ("kobject: copy env blob in one go")
>>> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.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.
>