Any kind of heavier load freezes Xorg completely

Soptik · 2020-09-20 01:26:54

Hi,

First of all, I'm sorry to the forum moderators if this is wrong forum category, I wasn't sure where to put it. It would probably fit better into the system administration one, but it's locked.

Anyway, in recent days, I had to perform heavier operations and I noticed that Xorg (well, I can't even alt+Fx into another tty, so I don't know if the issue is isolated just to X) freezes compeltely. I can't move mouse, I can't do anything, nothing reacts to any kind of user input.

This is triggered by operations that *do not* and *should not* deplete system resources - such as unzipping zip archive - which is large (1.2G), but as I'm unzipping it with one thread only, I see no way how resource exhaustion could freeze my whole computer under normal circumstances. Especially since it was located on fast SSD.

Those freezes were triggered by large pacman installs (Wolfram Mathematica, package of total size about 8.6 GiB) and even GPG encryption of large (18G) files on non-system hdd (!) - I see no way how could 1-thread-consuming operation on non-system hdd cause resource exhaustion, assuming I had enough ram (which was used to about two thirds at the time, so more than enough).

This all is weird to me, especially since I have quite good hw (20G of RAM, 8 cores cpu) and I never noticed anything like this before.

I'm using LTS kernel - `5.4.65-1-lts`.

I know this is vague, extremely hard to debug, non-exact and everything, but does anyone have any idea what could be the cause? Could it be because of the kernel? I recently switched to LTS when my mic didn't work on latest kernel shipped by default, but I don't know whether it's the cause. I didn't need this kind of heavy operations before, so I don't know what is the cause.

Is there for example a way to globally lower priority on such processes that might freeze the system? I know I can change priority for cpu usage or disk usage for individual processes, but I have no idea how to do so automatically, rather than manually for each one. I don't care if the encryption finishes in five minutes or fifteen minutes. I just want always-responsive system.

Edit: this seems triggered mainly by large memory allocations.

Thanks

Last edited by Soptik (2020-09-20 04:17:23)

seth · 2020-09-20 07:19:26

"I can't even alt+Fx into another tty" frozen GPU or kernel halted. I assume you can neither ssh into the system?

weird to me, especially since I have quite good hw

Quite good HW can be quite the problem. You should record the outputs of lspci and lscpu. There're several "freeze" threads in the kernel subforum, esp. Ryzen related.
You should seek to isolate the cause, https://wiki.archlinux.org/index.php/Stress_testing - from the described symptoms rather the disk (filesystem) or RAM (memtest86+, run several full cycles which is gonna take a while on 20GB - certainly a night)

Edit: testing the behavior w/ other kernels or software stacks (live distro, grml, knoppix, ubuntu, whatnot) to check whether it's a HW or SW issue is certainly a good idea as well.

Last edited by seth (2020-09-20 07:20:50)

solskog · 2020-09-20 09:37:11

A dedicated headless (without X) Virtual machine with limited CPU/RAM could be a solution.

ewaller · 2020-09-20 14:48:41

Soptk: Does it ever recover? Does it become very unresponsive totally unresponsive? Any chance you are experiencing a kernel panic?

solskog: Huh?

Arch Linux

#1 2020-09-20 01:26:54

Any kind of heavier load freezes Xorg completely

#2 2020-09-20 07:19:26

Re: Any kind of heavier load freezes Xorg completely

#3 2020-09-20 09:37:11

Re: Any kind of heavier load freezes Xorg completely

#4 2020-09-20 14:48:41

Re: Any kind of heavier load freezes Xorg completely

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