Re: [Bug 1884719] [NEW] Function not implemented when using libaio

[Stefan Hajnoczi]

On Tue, Jun 23, 2020 at 07:39:58AM -0000, Martin Grigorov wrote:
> Public bug reported:

CCing Filip and Laurent, who may be interested in adding Linux AIO
syscalls to qemu-user.

> 
> Hello
> 
> I experience "Function not implemented" errors when trying to use Linux
> libaio library in foreign architecture, e.g. aarch64.
> 
> I've faced this problem while using 
> https://github.com/multiarch/qemu-user-static, i.e. Docker+QEMU. 
> I understand that I do not use plain QEMU and you may count this report as a 
> "distribution of QEMU"! Just let me know what are the steps to test it with 
> plain QEMU and I will test and update this ticket!
> 
> 
> Here are the steps to reproduce the issue:
> 
> 1) On x86_64 machine register QEMU:
> 
>     `docker run -it --rm --privileged multiarch/qemu-user-static --reset
> --credential yes --persistent yes`
> 
> 2) Start a Docker image with foreign CPU architecture, e.g. aarch64
> 
>     `docker run -it arm64v8/centos:8 bash`
> 
> 3) Inside the Docker container install GCC and libaio
> 
>     `yum install gcc libaio libaio-devel`
> 
> 4) Compile the following C program
> 
> ```
> #include <stdio.h>
> #include <errno.h>
> #include <libaio.h>
> #include <stdlib.h>
> 
> struct io_control {
>     io_context_t ioContext;
> };
> 
> int main() {
>     int queueSize = 10;
> 
>     struct io_control * theControl = (struct io_control *) 
> malloc(sizeof(struct io_control));
>     if (theControl == NULL) {
>         printf("theControl is NULL");
>         return 123;
>     }
> 
>     int res = io_queue_init(queueSize, &theControl->ioContext);
>     io_queue_release(theControl->ioContext);
>     free(theControl);
>     printf("res is: %d", res);
> }
> ```
> 
>     ```
>     cat > test.c
>         [PASTE THE CODE ABOVE HERE]
>     ^D
>     ```
> 
>     `gcc test.c -o out -laio && ./out`
> 
> 
> When executed directly on aarch64 machine (i.e. without emulation) or on 
> x86_64 Docker image (e.g. centos:8) it prints `res is: 0`, i.e. it 
> successfully initialized a LibAIO queue.
> 
> But when executed on Docker image with foreign/emulated CPU architecture
> it prints `res is: -38` (ENOSYS). `man io_queue_init` says that error
> ENOSYS is returned when "Not implemented."
> 
> Environment:
> 
> QEMU version: 5.0.0.2  
> (https://github.com/multiarch/qemu-user-static/blob/master/.travis.yml#L24-L28)
> Container application: Docker
> Output of `docker --version`:
> 
> ```
> Client:
>  Version:           19.03.8
>  API version:       1.40
>  Go version:        go1.13.8
>  Git commit:        afacb8b7f0
>  Built:             Wed Mar 11 23:42:35 2020
>  OS/Arch:           linux/amd64
>  Experimental:      false
> 
> Server:
>  Engine:
>   Version:          19.03.8
>   API version:      1.40 (minimum version 1.12)
>   Go version:       go1.13.8
>   Git commit:       afacb8b7f0
>   Built:            Wed Mar 11 22:48:33 2020
>   OS/Arch:          linux/amd64
>   Experimental:     false
>  containerd:
>   Version:          1.3.3-0ubuntu2
>   GitCommit:        
>  runc:
>   Version:          spec: 1.0.1-dev
>   GitCommit:        
>  docker-init:
>   Version:          0.18.0
>   GitCommit:        
> ```
> 
> Same happens with Ubuntu (arm64v8/ubuntu:focal).
> 
> I've tried to `strace` it but :
> 
> ```
> /usr/bin/strace: ptrace(PTRACE_TRACEME, ...): Function not implemented
> /usr/bin/strace: PTRACE_SETOPTIONS: Function not implemented
> /usr/bin/strace: detach: waitpid(112): No child processes
> /usr/bin/strace: Process 112 detached
> ```
> 
> Here are the steps to reproduce the problem with strace:
> 
>      ```
>      docker run --rm -it --security-opt seccomp:unconfined --security-opt 
> apparmor:unconfined --privileged --cap-add ALL arm64v8/centos:8 bash
> 
>      yum install -y strace`
> 
>      strace echo Test
>      ```
> 
> Note: I used --privileged, disabled seccomp and apparmor, and added all
> capabilities
> 
> Disabling security solves the "Permission denied" problem but then comes
> the "Not implemented" one.
> 
> 
> Any idea what could be the problem and how to work it around ?
> I've googled a lot but I wasn't able to find any problems related to libaio 
> on QEMU.
> 
> Thank you!
> Martin
> 
> ** Affects: qemu
>      Importance: Undecided
>          Status: New
> 
> -- 
> You received this bug notification because you are a member of qemu-
> devel-ml, which is subscribed to QEMU.
> https://bugs.launchpad.net/bugs/1884719
> 
> Title:
>   Function not implemented when using libaio
> 
> Status in QEMU:
>   New
> 
> Bug description:
>   Hello
> 
>   I experience "Function not implemented" errors when trying to use
>   Linux libaio library in foreign architecture, e.g. aarch64.
> 
>   I've faced this problem while using 
> https://github.com/multiarch/qemu-user-static, i.e. Docker+QEMU. 
>   I understand that I do not use plain QEMU and you may count this report as 
> a "distribution of QEMU"! Just let me know what are the steps to test it with 
> plain QEMU and I will test and update this ticket!
> 
>   
>   Here are the steps to reproduce the issue:
> 
>   1) On x86_64 machine register QEMU:
> 
>       `docker run -it --rm --privileged multiarch/qemu-user-static
>   --reset --credential yes --persistent yes`
> 
>   2) Start a Docker image with foreign CPU architecture, e.g. aarch64
> 
>       `docker run -it arm64v8/centos:8 bash`
> 
>   3) Inside the Docker container install GCC and libaio
> 
>       `yum install gcc libaio libaio-devel`
> 
>   4) Compile the following C program
> 
>   ```
>   #include <stdio.h>
>   #include <errno.h>
>   #include <libaio.h>
>   #include <stdlib.h>
> 
>   struct io_control {
>       io_context_t ioContext;
>   };
> 
>   int main() {
>       int queueSize = 10;
> 
>       struct io_control * theControl = (struct io_control *) 
> malloc(sizeof(struct io_control));
>       if (theControl == NULL) {
>           printf("theControl is NULL");
>           return 123;
>       }
> 
>       int res = io_queue_init(queueSize, &theControl->ioContext);
>       io_queue_release(theControl->ioContext);
>       free(theControl);
>       printf("res is: %d", res);
>   }
>   ```
> 
>       ```
>       cat > test.c
>           [PASTE THE CODE ABOVE HERE]
>       ^D
>       ```
> 
>       `gcc test.c -o out -laio && ./out`
> 
>   
>   When executed directly on aarch64 machine (i.e. without emulation) or on 
> x86_64 Docker image (e.g. centos:8) it prints `res is: 0`, i.e. it 
> successfully initialized a LibAIO queue.
> 
>   But when executed on Docker image with foreign/emulated CPU
>   architecture it prints `res is: -38` (ENOSYS). `man io_queue_init`
>   says that error ENOSYS is returned when "Not implemented."
> 
>   Environment:
> 
>   QEMU version: 5.0.0.2  
> (https://github.com/multiarch/qemu-user-static/blob/master/.travis.yml#L24-L28)
>   Container application: Docker
>   Output of `docker --version`:
> 
>   ```
>   Client:
>    Version:           19.03.8
>    API version:       1.40
>    Go version:        go1.13.8
>    Git commit:        afacb8b7f0
>    Built:             Wed Mar 11 23:42:35 2020
>    OS/Arch:           linux/amd64
>    Experimental:      false
> 
>   Server:
>    Engine:
>     Version:          19.03.8
>     API version:      1.40 (minimum version 1.12)
>     Go version:       go1.13.8
>     Git commit:       afacb8b7f0
>     Built:            Wed Mar 11 22:48:33 2020
>     OS/Arch:          linux/amd64
>     Experimental:     false
>    containerd:
>     Version:          1.3.3-0ubuntu2
>     GitCommit:        
>    runc:
>     Version:          spec: 1.0.1-dev
>     GitCommit:        
>    docker-init:
>     Version:          0.18.0
>     GitCommit:        
>   ```
> 
>   Same happens with Ubuntu (arm64v8/ubuntu:focal).
> 
>   I've tried to `strace` it but :
> 
>   ```
>   /usr/bin/strace: ptrace(PTRACE_TRACEME, ...): Function not implemented
>   /usr/bin/strace: PTRACE_SETOPTIONS: Function not implemented
>   /usr/bin/strace: detach: waitpid(112): No child processes
>   /usr/bin/strace: Process 112 detached
>   ```
> 
>   Here are the steps to reproduce the problem with strace:
> 
>        ```
>        docker run --rm -it --security-opt seccomp:unconfined --security-opt 
> apparmor:unconfined --privileged --cap-add ALL arm64v8/centos:8 bash
> 
>        yum install -y strace`
> 
>        strace echo Test
>        ```
> 
>   Note: I used --privileged, disabled seccomp and apparmor, and added
>   all capabilities
> 
>   Disabling security solves the "Permission denied" problem but then
>   comes the "Not implemented" one.
> 
>   
>   Any idea what could be the problem and how to work it around ?
>   I've googled a lot but I wasn't able to find any problems related to libaio 
> on QEMU.
> 
>   Thank you!
>   Martin
> 
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/qemu/+bug/1884719/+subscriptions
>

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