jcmd uses src/jdk.internal.jvmstat/linux/classes/sun/jvmstat/PlatformSupportImpl.java to scan temporary directories to find out processes in the container. It checks inode to ensure the temp directory is not conflicted. However inode maybe same value between the container and others. Thus we should check device id for that case.
For example I saw following case on [distroless cc-debian11](https://github.com/GoogleContainerTools/distroless/blob/main/cc/README.md) container. I started rescue:jdk19 container with sharing PID namespace. `/proc/1/root/tmp` is different from `/tmp` on rescue:jdk19, but they are same inode value. However we can see the differense in device id. $ podman run -it --rm --entrypoint=sh --pid=container:fa39662f7352 rescue:jdk19 / # / # stat /tmp File: /tmp Size: 29 Blocks: 0 IO Block: 4096 directory Device: efh/239d Inode: 135674931 Links: 1 Access: (1777/drwxrwxrwt) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2022-04-05 08:51:37.000000000 Modify: 2022-04-05 08:51:37.000000000 Change: 2022-04-05 08:51:37.000000000 / # stat /proc/1/root/tmp File: /proc/1/root/tmp Size: 29 Blocks: 0 IO Block: 4096 directory Device: e1h/225d Inode: 135674931 Links: 1 Access: (1777/drwxrwxrwt) Uid: ( 0/ root) Gid: ( 0/ root) Access: 2022-04-05 08:51:37.000000000 Modify: 2022-04-05 08:50:42.000000000 Change: 2022-04-05 08:50:42.000000000 ------------- Commit messages: - 8284330: jcmd may not be able to find processes in the container Changes: https://git.openjdk.java.net/jdk/pull/8103/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8103&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8284330 Stats: 42 lines in 1 file changed: 27 ins; 10 del; 5 mod Patch: https://git.openjdk.java.net/jdk/pull/8103.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/8103/head:pull/8103 PR: https://git.openjdk.java.net/jdk/pull/8103
