Why would userdel report that a user is currently used by a process that is running as another user?

stackhatter

5/5/23, 10:20 PM

When attempting to delete userA, userdel reported that userA is currently used by process 1296; however, ps reported that this process was running as userB. userC ran userdel.

userdel: user **userA** is currently used by process 1296
(base) **userC**@server:/dir1/home$ ps -aux | grep 1296
**userB**  1296  0.0  0.0  21604  5096 pts/0    Ss   Jan02   0:00 /bin/bash -l

Distro name and version:

(base) userB@server:~$ uname -a Linux server 4.15.0-135-generic #139-Ubuntu SMP Mon Jan 18 17:38:24 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

(base) userB@server:~$ id userA uid=1000(userA) gid=1000(userA) groups=1000(userA)

(base) userB@server:~$ id userB uid=000000(userB) gid=000000(userB) groups=000000(userB),00(sudo),000(lxd),000(libvirt),0000000(groupB),00000(groupB)

NB: The number of 0s reflects the number of digits in the number.

168

0 + 0

linux

bash

Bofa Deez

5/5/23, 11:03 PM

Please provide more information such as: Distro name and version, output of `id usera` and `id userb`, `ps -aux --forest` output of the entire tree that 1296 exists in, and an `strace` of the `userdel`

AlexD

5/6/23, 11:31 AM

It is possible that both `userA` and `userB` have the same UID.

Bofa Deez

5/6/23, 5:20 PM

When I attempt to do make that happen manually with useradd, I get an error that the UID is already in use. Stackhatter could have manually edited their /etc/passwd to have two users with the same UID, but in this case I am not able to replicate the original error message from the OP on my Alpine test VM, which is why I also asked for distro name and version.

stackhatter

5/6/23, 6:11 PM

Process 1296 has been killed; hence, we cannot provide the other requested details on it.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Why would userdel report that a user is currently used by a process that is running as another user?

TH: เหตุใด userdel จึงรายงานว่าผู้ใช้กำลังใช้งานโดยกระบวนการที่กำลังทำงานในฐานะผู้ใช้รายอื่น

RO: De ce ar raporta userdel că un utilizator este utilizat în prezent de un proces care rulează ca alt utilizator?

RU: Почему userdel сообщает, что пользователь в настоящее время используется процессом, который выполняется от имени другого пользователя?

VI: Tại sao userdel báo cáo rằng một người dùng hiện đang được sử dụng bởi một quy trình đang chạy với tư cách là một người dùng khác?

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