Stopped (ctrl z) process will not restart, and no longer in job list

Question

I was running apt upgrade, when I needed the terminal, so did a ctrlz. When I tried to restart it (fg), it would not restart, because it was no-longer in the jobs list (jobs). (I Did not, run disown). I then did a ps to get process id. It showed the process to be stopped (as expected), so I then did sudo kill -s SIGCONT pid, to re-start it, but nothing happened. ps showed that process was still stopped. There was no error message.

What I did.

sudo apt upgrade
«wait a bit»
«ctrl-z»
«some other command» #can't remember, but nothing special.
fg #This command failed, no such job
jobs #No output

What I tried to fix it.

send sigcont to apt
send sigcont to sudo
What happened for the shell to disown the process?
(more importantly) How do I re-start it?

Output from ps -l -p $(pgrep apt)

F S   UID   PID  PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD
4 T     0 22884 22883  0  80   0 - 21617 -      pts/1    00:00:01 apt

Output from pstree -s -p $(pgrep apt)

systemd(1)───kdeinit5(1038)───ksmserver(1062)───yakuake(1153)───bash(1225)───sudo(22883)───apt(22884)

Output from pgrep bash | xargs -n1 ps -l -p

F S   UID   PID  PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD
0 S  1000  1225  1153  0  80   0 -  8770 core_s pts/1    00:00:00 bash
F S   UID   PID  PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD
0 S  1000  3852  3849  0  80   0 -  8404 -      pts/7    00:00:00 bash
F S   UID   PID  PPID  C PRI  NI ADDR SZ WCHAN  TTY          TIME CMD
0 S  1000  4449  4445  0  80   0 -  8392 core_s pts/3    00:00:01 bash
⋮

Ideas: has it lost contact with stdout/stdin?, does it need it?

System Debian, bash

#↳ bash --version
GNU bash, version 4.3.30(1)-release (x86_64-pc-linux-gnu)

#↳ uname -a
Linux delorenzi 3.16.0-5-amd64 #1 SMP Debian 3.16.51-3+deb8u1 (2018-01-08) x86_64 GNU/Linux

#↳ sudo --version
Sudo version 1.8.10p3
Sudoers policy plugin version 1.8.10p3
Sudoers file grammar version 43
Sudoers I/O plugin version 1.8.10p3

What happens when you use the fg command in that shell session? — Kusalananda, Apr 03 '18 at 13:47
Important information missing from the question: The process tree, demonstrating which shell is the parent of the apt-get process and which shell is the one running fg. — JdeBP, Apr 03 '18 at 17:40
@MarkPlotnick done: adding output to ps -l -p $(pgrep apt) to question. — ctrl-alt-delor, Apr 04 '18 at 12:20
@JdeBP done: added output to pstree -s $(pgrep apt) to the question. — ctrl-alt-delor, Apr 04 '18 at 12:23
Do you not have a job for the sudo? If you don't have a job, then you can't continue the task. Sending a SIGCONT won't work since the program will just go back to trying to read from the terminal, and since it is not in the foreground process group, it gets stopped again. — psusi, Apr 04 '18 at 12:54
@psusi jobs returns nothing (don't know why it was disowned). Can I attach it to another tty, or other stdin/stdout? — ctrl-alt-delor, Apr 04 '18 at 12:57
Can you find the window with the bash that's pid 1225 (run echo $$ to each shell to see its pid), then type jobs to it? — Mark Plotnick, Apr 04 '18 at 14:21
@MarkPlotnick Yes I have that window. It is running yakuke, but jobs returns nothing. — ctrl-alt-delor, Apr 05 '18 at 09:20
@ctrl-alt-delor is «ctrl-c» in your first snippet a typo? Assuming it is, however if it isn't, there was no background job to begin with and this is some other apt process. — yahol, Apr 06 '18 at 12:09
@yahol, yes a typo (I fixed it). I know I did «ctrl-z» as I can do a ps and see that the process is now stopped. It just does not appear in the jobs list. — ctrl-alt-delor, Apr 06 '18 at 15:43

score 1 · Answer 1 · answered Sep 25 '18 at 17:05

1

The usual culprit to suspect would be an honest confusion. The most obvious place to check is that you are running jobs from a shell whose PID matches the expected one (1225). In the comments you mention that you have the terminal, but I am suspecting the "some other command" may have started another shell? Did you confirm the $$ of the shell you are running jobs from?

answered Sep 25 '18 at 17:05

chutz

226

It was a while ago, I think I tried that. If I have the problem again, I will read your answer, and the comments. If I solve it I will add an answer. – ctrl-alt-delor Sep 25 '18 at 17:11

Stopped (ctrl z) process will not restart, and no longer in job list

1 Answers1