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Subject: Re: [PATCH 4.19 21/57] proc: dont allow async path resolution of
 /proc/self components
To:     Yang Yingliang <yangyingliang@huawei.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-kernel@vger.kernel.org
Cc:     stable@vger.kernel.org, Sasha Levin <sashal@kernel.org>,
        yangerkun <yangerkun@huawei.com>,
        Cheng Jian <cj.chengjian@huawei.com>
References: <20201201084647.751612010@linuxfoundation.org>
 <20201201084650.205087954@linuxfoundation.org>
 <cced67ae-ceca-3812-121c-70e0ed104f49@huawei.com>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <395dd137-70d5-e915-92b5-b2a18f44badc@kernel.dk>
Date:   Tue, 2 Mar 2021 10:39:08 -0700
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On 3/2/21 1:40 AM, Yang Yingliang wrote:
> Hi,
> 
> On 2020/12/1 16:53, Greg Kroah-Hartman wrote:
>> From: Jens Axboe <axboe@kernel.dk>
>>
>> [ Upstream commit 8d4c3e76e3be11a64df95ddee52e99092d42fc19 ]
>>
>> If this is attempted by a kthread, then return -EOPNOTSUPP as we don't
>> currently support that. Once we can get task_pid_ptr() doing the right
>> thing, then this can go away again.
> 
> https://www.spinics.net/lists/io-uring/msg05297.html
> 
> This patch seems used for io-wq worker which is merged in
> 
> v5.5-rc1, why we need this in linux-4.19.y ?

While that's true, it's also a sane safeguard in general.

-- 
Jens Axboe