Re: [Syzkaller & bisect] There is "io_ring_exit_work" related Call Trace in v5.2-rc5 kernel

[Jens Axboe]

On 2/2/23 1:56 AM, Pengfei Xu wrote:
> Hi Pavel Begunkov,
> 
> On 2023-02-01 at 15:52:47 +0000, Pavel Begunkov wrote:
>> On 1/28/23 14:49, Pavel Begunkov wrote:
>>> On 1/28/23 08:44, Pengfei Xu wrote:
>>>> Hi Pavel Begunkov and kernel expert,
>>>>
>>>> Greeting!
>>>>
>>>> There is "io_ring_exit_work" related Call Trace in v5.2-rc5 kernel in guest
>>>> on Sapphire Rapids server.
>>>
>>> Thanks for the report, we'll take a look
>>
>> Not reproducible for me. Apparently, the repro creates a normal ring
>> and immediately closes it, then io_ring_exit_work() hangs waiting to
>> the task to execute task_work.
>   Ah, I put the reproduced virtual machine in gitlab.
>   git clone https://gitlab.com/xupengfe/repro_vm_env.git
>   cd repro_vm_env
>   tar -xvf repro_vm_env.tar.gz
>   cd repro_vm_env; ./start3.sh  // it needs qemu-system-x86_64 and I used v7.1.0
>      //start3.sh will load bzImage_2241ab53cbb5cdb08a6b2d4688feb13971058f65 v6.2-rc5 kernel
>   In vm and login with root,  there is no password for root.
>   After login vm successfully, ./repro   to reproduce this issue.
>   It could be reproduced in about 6min.
> 
>   If you already have qemu-system-x86_64, please ignore below info.
>   If you want to install qemu v7.1.0 version,
>   git clone https://github.com/qemu/qemu.git
>   cd qemu
>   git checkout -f v7.1.0
>   mkdir build
>   cd build
>   yum install -y ninja-build.x86_64
>   ../configure --target-list=x86_64-softmmu --enable-kvm --enable-vnc --enable-gtk --enable-sdl
>   make
>   make install
>   Done.

Are you sure you attached the right kconfig in the initial report? It
is from 5.18.x.

-- 
Jens Axboe