Helix crashes and kills terminal emulator when opening a large file with clangd.

[grantshandy]

Summary

When opening a large file with helix (cosmopolitan.h), my computer (Ryzen 9 5900x, 16GB RAM) goes up to 100% memory and not only does helix crash, my terminal emulator crashes too. It's not that unexpected to see a text editor crash opening a huge file, but I didn't expect it to also take my terminal emulator on the way.

This crash is not terminal-emulator specific, I've reproduced it in both kitty and alacritty.

The errors I get from the system and from helix say that it's related to clangd. If this is a clangd bug should I report it there/should helix find a way to avoid this type of crash? Completely crashing the whole editor as well as the surrounding terminal emulator seems like something that should be pretty high-priority.

Reproduction Steps

From what I can tell, the only thing required to reproduce this is opening cosmopolitan.h (presumably with clangd installed as I'll get to).

$ wget https://justine.lol/cosmopolitan/cosmopolitan-amalgamation-2.2.zip
$ unzip cosmopolitan-amalgamation-2.2.zip
$ helix cosmopolitan.h

Helix log

I was unable to collect any panic info as it takes the terminal emulator on its way out, but I was able to scrounge up some information from journalctl's logs as well as helix's log file.

Error in system logs:

Out of memory: Killed process 27936 (clangd.main) total-vm:18361524kB, anon-rss:13132908kB, file-rss:4864kB, shmem-rss:192kB, UID:1000 pgtables:34024kB oom_score_adj:100

I assume the system log says that it killed the process because it ran out of memory (makes sense). My main question is why the system decided to take out the what I assume are its parent processes.

Here's the last thing in ~/.cache/helix/helix.log:

2023-03-15T15:17:14.130 helix_view::document [DEBUG] id 1 modified - last saved: 0, current: 0
2023-03-15T15:17:14.139 helix_lsp::transport [ERROR] err <- "I[15:17:14.139] <-- textDocument/didOpen\n"
2023-03-15T15:17:14.141 helix_lsp::transport [ERROR] err <- "I[15:17:14.141] Failed to find compilation database for /home/grant/Documents/cosmo/cosmopolitan.h\n"
2023-03-15T15:17:14.141 helix_lsp::transport [ERROR] err <- "I[15:17:14.141] ASTWorker building file /home/grant/Documents/cosmo/cosmopolitan.h version 0 with command clangd fallback\n"
2023-03-15T15:17:14.141 helix_lsp::transport [ERROR] err <- "[/home/grant/Documents/cosmo]\n"
2023-03-15T15:17:14.141 helix_lsp::transport [ERROR] err <- "/usr/bin/clang -xobjective-c++-header -resource-dir=/usr/lib/clang/15.0.7 -- /home/grant/Documents/cosmo/cosmopolitan.h\n"
2023-03-15T15:17:14.255 helix_term::application [DEBUG] received editor event: IdleTimer

Platform

Arch Linux

Terminal Emulator

Kitty 0.27.1 / Alacritty 0.11.0

Helix Version

Helix 22.12

[pascalkuthe]

This issue is likely tree-sitter-related. It looks like something got stuck somewhere and consumed all your memory. The linux OOM killer is fairly indiscriminate and likely killed the terminal because helix was a child process.

I can't reproduce this problem on latest master. The file opens fairly quickly and scrolling it is actually quite smooth.
We recently updated to a new TS version that has a large performance improvement for huge headers like this so I think that's probably the reason. Another reason might be that the TS grammar for C was also updated so that might be another reason.

Please test if the problem still occurs for you with a build from the master branch.

[grantshandy]

I compiled helix from the main branch and tried again, same result. Clangd goes up to 100% memory usage and the linux OOM killer shuts down clangd, helix, and the terminal emulator. I'll do some research to see if this has been found before with clangd.

[vlada-dudr]

Terminal is killed likely because systemd kills whole cgroup during oom condition. I assume you are using a DE which starts it's child processes in independent cgroups like Gnome, otherwise it would kill whole session.