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Date:   Wed, 11 Jan 2023 19:37:55 -0700
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Subject: Re: [PATCH] io_uring: Add NULL checks for current->io_uring
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To:     Jia-Ju Bai <baijiaju1990@gmail.com>, asml.silence@gmail.com
Cc:     io-uring@vger.kernel.org, linux-kernel@vger.kernel.org,
        TOTE Robot <oslab@tsinghua.edu.cn>
References: <20230111101907.600820-1-baijiaju1990@gmail.com>
 <63d8e95e-894c-4268-648e-35e504ea80b6@kernel.dk>
 <a2d622dc-a28e-acf7-2863-a2a0310c8697@gmail.com>
From:   Jens Axboe <axboe@kernel.dk>
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On 1/11/23 7:10 PM, Jia-Ju Bai wrote:
> 
> 
> On 2023/1/11 22:49, Jens Axboe wrote:
>> On 1/11/23 3:19 AM, Jia-Ju Bai wrote:
>>> As described in a previous commit 998b30c3948e, current->io_uring could
>>> be NULL, and thus a NULL check is required for this variable.
>>>
>>> In the same way, other functions that access current->io_uring also
>>> require NULL checks of this variable.
>> This seems odd. Have you actually seen traces of this, or is it just
>> based on "guess it can be NULL sometimes, check it in all spots"?
>>
> 
> Thanks for the reply!
> I checked the previous commit and inferred that there may be some problems.
> I am not quite sure of this, and thus want to listen to your opinions :)

I'd invite you to look over each of them separately, and see if that path
could potentially lead to current->io_uring == NULL and thus being an
issue. I think that'd be a useful exercise, and you never know that you
might find :-)

-- 
Jens Axboe