Figure out process involved in out of memory (OOM) #95

New Issue

2026-03-20T15:40:23+01:00

Benjamin_Loison commented

2026-03-20 15:40:23 +01:00

Would help:

As far as I understand, even with possibly reserved system memory as it may exceed it may involve system crash, so there is no user process to blame. Can double reserved system memory to reduce the risk and figure out what user process was possibly unexpectedly behaving.

<details> <summary>Would help:</summary> ``` -----BEGIN PGP MESSAGE----- hF4DTQa9Wom5MBgSAQdA6PfZqqR0hAz2rgsVX9NJbqKOQTF/oDJzlm8kyOH7/S8w Ao1O4ph/jBjVI5ApZgoKVteUeh4v4pAPxeBWyqc9UgV33r6J/hZbkjtrZMkI5WIr 1LcBCQIQC7tLFfVx8TXZk26td7HbDm/yJzi9DFHSPNnuzeXEYwQzzDeuVyTMrBlD vgbGDGQfKUg+0lyGgSx/dJtnH67RMlrdybYPkc8UA8TWeeh+BOsDp9+Z13AwSwM5 xdHWt97sxgXTRE0AGDuahz05+vpcLNfFh3Q14TWa6Nm4I3yEYF9a1jCa8cDpnyVf c5qkfXOxDgZdKhfFId8sdRi7rKM826TKhafzibIZKQixAEAiw42X3Rg= =TgKU -----END PGP MESSAGE----- ``` </details> As far as I understand, even with possibly reserved system memory as it may exceed it may involve system crash, so there is no user process to blame. Can double reserved system memory to reduce the risk and figure out what user process was possibly unexpectedly behaving.

Benjamin_Loison commented

2026-04-04 00:31:21 +02:00

I involved this issue this time:

<details> <summary>I involved this issue this time:</summary> ``` -----BEGIN PGP MESSAGE----- hF4DTQa9Wom5MBgSAQdAgZPRwG8ZM2BkLUGeiSDnOzXZpr0akVSzEpVcnTf9HGsw XAWPKyd7Vwsu7HT/BfI5u0JRUm9VSw1U/h6FmZyb/lYH5dxbAjEfZQ06K3CggfTw 1LcBCQIQjRUnwG/N6J1ch8lFzyPxfZD9QtJ6oUDKL8ir6oF4hiM59xiNrnYDKgRw qVcaTosr075Sk2nM6ORc/ilwO7kBddB8wZeSMQnU2gurqS9ITrgL2WFzCRmt9PgZ dxKQ9w1kCtYm888/7K1IilVjJqIM0PR6L4acAs1SNYxo4lt5gm7833cs2Gvp9Ci3 ifzbspEhV0CjOWmU9+3TvjFLR4YHfpYCYNCEY5aJhOoGpVZGYoOzigo= =PL4L -----END PGP MESSAGE----- ``` </details>

Benjamin_Loison commented

2026-04-04 01:11:26 +02:00

DuckDuckGo and Google search Linux command to claim memory, Linux command to book memory and Linux command to allocate memory.

The Unix Stack Exchange answer 254976:

head -c 5G /dev/zero | pv | tail | sleep 60

5,00GiB 0:00:03 [1,28GiB/s] [  <=>                           ]

DuckDuckGo and Google search *Linux command to claim memory*, *Linux command to book memory* and *Linux command to allocate memory*. [The Unix Stack Exchange answer 254976](https://unix.stackexchange.com/a/254976): ```bash head -c 5G /dev/zero | pv | tail | sleep 60 ``` ``` 5,00GiB 0:00:03 [1,28GiB/s] [ <=> ] ```

Benjamin_Loison commented

2026-04-04 01:12:53 +02:00

On my Linux Mint 22.3 Cinnamon Framework 13 Virtual Machine Manager Linux Mint (trust) virtual machine with 15.6 GB of RAM and 1.83 GB of swap.

head -c 30G /dev/zero | pv | tail | sleep 60

15,7GiB 0:00:27 [ 578MiB/s] [                <=>             ]

hangs while htop does not show consumption contrarily to above.

On my Linux Mint 22.3 Cinnamon Framework 13 Virtual Machine Manager *Linux Mint (trust)* virtual machine with 15.6 GB of RAM and 1.83 GB of swap. ```bash head -c 30G /dev/zero | pv | tail | sleep 60 ``` ``` 15,7GiB 0:00:27 [ 578MiB/s] [ <=> ] ``` hangs while `htop` does not show consumption contrarily to above.

Benjamin_Loison commented

2026-04-04 01:14:07 +02:00

head -c 30G /dev/zero | pv | tail

Output:

15,7GiB 0:00:18 [ 873MiB/s] [           <=>                  ]
Killed

as wanted.

```bash head -c 30G /dev/zero | pv | tail ``` <details> <summary>Output:</summary> ``` 15,7GiB 0:00:18 [ 873MiB/s] [ <=> ] Killed ``` </details> as wanted.

Benjamin_Loison commented

2026-04-04 01:14:51 +02:00

Before investigating security, should verify this witness behavior on the considered computer.

https://pim.etesync.lemnoslife.com/pim/events/OQi24uZ0O6onZ1B66Ba16CZEpDCY35-G|rSmlIgFJdljz0Kd2jZUg3dspQfclImv0

Before investigating security, should verify this witness behavior on the considered computer. [https://pim.etesync.lemnoslife.com/pim/events/OQi24uZ0O6onZ1B66Ba16CZEpDCY35-G|rSmlIgFJdljz0Kd2jZUg3dspQfclImv0](https://pim.etesync.lemnoslife.com/pim/events/OQi24uZ0O6onZ1B66Ba16CZEpDCY35-G%7CrSmlIgFJdljz0Kd2jZUg3dspQfclImv0)

Benjamin_Loison referenced this issue

2026-06-09 16:37:23 +02:00

How to limit RAM usage for my user or a given program? #102

Benjamin_Loison commented

2026-06-10 12:58:24 +02:00

According to the person:

the OOM killer struggles figuring out which process takes too much memory and emits tens of thousands to journald which makes it crash. So he plans on setting RAM limit by user like 64 GB (which is too low for some of my usage as well as for some other persons as far as I know, I told him), which should limit the issue.

He implemented such a rule, see his message:

<details> <summary>According to the person:</summary> ``` -----BEGIN PGP MESSAGE----- hF4DTQa9Wom5MBgSAQdA9VdsP3CC0bBEJI77it60Z0rOa0i37H7znPH2yyQD/Qww iZYkUOR21uwGyJwWEhlD/ZkW52tkIrG7V6NWF4J9bh4H3rcHFdNrAVTt2XucFJot 0kEBhS0vbVqRu8qu04ooucnXNqxezT/P+2VVF2571lhqobWta4JHKpfwgjIIxIqc tQAdhSa1Y5h6pKSGqf9qV+HytA== =Wrpj -----END PGP MESSAGE----- ``` </details> the OOM killer struggles figuring out which process takes too much memory and emits tens of thousands to journald which makes it crash. So he plans on setting RAM limit by user like 64 GB (which is too low for some of my usage as well as for some other persons as far as I know, I told him), which should limit the issue. <details> <summary>He implemented such a rule, see his message:</summary> ``` -----BEGIN PGP MESSAGE----- hF4DTQa9Wom5MBgSAQdANVK+xLwg1UxLOKwA0m/+geMusjUPTjibBk4aKkZcZxQw LgLRUePFXnTetnSiZempEfQXHvqLcCRxDU9a3GsAtZhG3WGlnx7Ugw+PznIG5cgi 0q0BlsCDlmJ00hQ9dmPjKoLgSV71UclKArxtoxvOTY00drwNslcd+y6Clhr1Pnth yeOIMsZgsBXK6oSG0tqfTAwNMP3921Uq68xQwAOkSM6MsdqcEZS7L1hTjt5i/3hL e4FB+981Eif2O2O1f82mNrSMo32y4k4YCDsmO7xxiiAWyLdIJTrkrM9bdActuYju wqOBP/G2WPj4szh84tQuRKn7aHFiXfv+FcAIQ7neGw== =y6fh -----END PGP MESSAGE----- ``` </details>

Sign in to join this conversation.

1 Participants

Notifications

Due Date

No due date set.

Dependencies

No dependencies set.

Reference: Benjamin_Loison/linux#95