docker exec can not exit when run with pid namespace

[kamizjw]

Description

1.docker run a new container with pidnamespace
2.docker exec this container
3.docker rm -f this container
finally，docker exec is not exit，example like this：

 docker run -itd --pid=host busybox  sh
368ca7afbf63920b48fe200a3e41231c6411f728a9492e9c8df1c50413738303

[root@localhost ~]# docker exec -it 368ca7afbf63920b48fe200a3e41231c6411f728a9492e9c8df1c50413738303 sh
/ # 

docker rm in another shell windows
[root@localhost ~]# docker rm -f 368ca7afbf63920b48fe200a3e41231c6411f728a9492e9c8df1c50413738303
368ca7afbf63920b48fe200a3e41231c6411f728a9492e9c8df1c50413738303


observe that the exec process does not exit
[root@localhost ~]# docker exec -it 368ca7afbf63920b48fe200a3e41231c6411f728a9492e9c8df1c50413738303 sh
/ # 

result is that docker exec is not exit,but when we do not specify “--pid” parameters to run container，exec process exit successfully

Reproduce

1.docker run -itd --pid=host busybox sh
2.docker exec -it 368ca7afbf63920b48fe200a3e41231c6411f728a9492e9c8df1c50413738303 sh
3.docker rm -f 368ca7afbf63920b48fe200a3e41231c6411f728a9492e9c8df1c50413738303

Expected behavior

No response

docker version

Client: Docker Engine - Community
 Version:           20.10.23
 API version:       1.41
 Go version:        go1.18.10
 Git commit:        7155243
 Built:             Thu Jan 19 17:34:59 2023
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true

Server: Docker Engine - Community
 Engine:
  Version:          20.10.23
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.18.10
  Git commit:       6051f14
  Built:            Thu Jan 19 17:32:36 2023
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          
  GitCommit:        .m
 runc:
  Version:          1.1.3
  GitCommit:        b17d05d6bfb1f6d087f5585e5236ffc04173af69

docker info

Client:
 Context:    default
 Debug Mode: false

Server:
 Containers: 16
  Running: 0
  Paused: 0
  Stopped: 16
 Images: 20
 Server Version: 20.10.23
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 1
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 io.containerd.runtime.v1.linux runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: .m
 runc version: b17d05d6bfb1f6d087f5585e5236ffc04173af69
 init version: N/A
 Security Options:
  seccomp
   Profile: default
 Kernel Version: 5.10.0-60.18.0.50.h763.eulerosv2r11.x86_64
 Operating System: EulerOS 2.0 (SP11x86_64)
 OSType: linux
 Architecture: x86_64
 CPUs: 4
 Total Memory: 7.249GiB
 Name: localhost.localdomain
 ID: TNWQ:CZYP:AKFK:IA5Q:74RD:3NQK:J4QG:QF3J:JULD:EWBV:I26E:U45J
 Docker Root Dir: /var/lib/docker
 Debug Mode: true
  File Descriptors: 28
  Goroutines: 50
  System Time: 2023-03-09T10:17:24.793244491+08:00
  EventsListeners: 0
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  10.175.125.206:80
  127.0.0.0/8
 Live Restore Enabled: true

Additional Info

No response

[sam-thibault]

Some related items:

• [Carry 38704] Implement exec kill API #41548
• Kill docker exec command will not terminate the spawned process #9098

[kamizjw]

Some related items:

• [Carry 38704] Implement exec kill API #41548
• Kill docker exec command will not terminate the spawned process #9098

doesn't look like a same problem