linux-kernel - Re: [syzbot] [kernel?] KASAN: slab-use-after-free Read in thread_group

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Message-ID: <0bef178c-bb78-4afb-b144-fa2f733c173b@gmail.com>
Date: Fri, 10 Jan 2025 14:32:24 +0000
From: Pavel Begunkov <asml.silence@...il.com>
To: Jens Axboe <axboe@...nel.dk>, Dmitry Vyukov <dvyukov@...gle.com>,
 syzbot <syzbot+3d92cfcfa84070b0a470@...kaller.appspotmail.com>,
 io-uring@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [kernel?] KASAN: slab-use-after-free Read in
 thread_group_cputime

On 1/10/25 14:13, Jens Axboe wrote:
> On 1/10/25 7:13 AM, Pavel Begunkov wrote:
>> On 1/10/25 13:56, Dmitry Vyukov wrote:
>>> On Fri, 10 Jan 2025 at 14:51, syzbot
>>> <syzbot+3d92cfcfa84070b0a470@...kaller.appspotmail.com> wrote:
...
>>> #syz set subsystems: io-uring
>>>
>>> +maintainers
>>
>> Thanks. It probably needs something like below.
>>
>> diff --git a/io_uring/sqpoll.c b/io_uring/sqpoll.c
>> index 6df5e649c413..5768e31e99b1 100644
>> --- a/io_uring/sqpoll.c
>> +++ b/io_uring/sqpoll.c
>> @@ -268,8 +268,12 @@ static int io_sq_thread(void *data)
>>          DEFINE_WAIT(wait);
>>
>>          /* offload context creation failed, just exit */
>> -       if (!current->io_uring)
>> +       if (!current->io_uring) {
>> +               mutex_lock(&sqd->lock);
>> +               sqd->thread = NULL;
>> +               mutex_unlock(&sqd->lock);
>>                  goto err_out;
>> +       }
>>
>>          snprintf(buf, sizeof(buf), "iou-sqp-%d", sqd->task_pid);
>>          set_task_comm(current, buf);
> 
> Indeed - can you send that out and I can include it in this weeks pull?

Done

-- 
Pavel Begunkov