** Description changed: + [ Impact ] + + The gnome-shell process leaks shared memory from software-rendered + elements (like GTK3 windows) if they continue to redraw in the + background while not being displayed on screen, such as during the lock + screen. This primarily affects Intel GPUs due to a Mesa bug, but could + affect other drivers too. + + [ Test Plan ] + + 0. Find a machine with Intel graphics. + + 1. Install gnome-terminal (not ptyxis or any other terminal): + sudo apt install gnome-terminal + + 2. Log in via ssh to monitor resource usage: + while sleep 5; do grep Shm /proc/meminfo; done + + 3. Log in to the GNOME desktop and start a gnome-terminal window animating: + while sleep 1; do date; done + + 4. Lock the screen. + + 5. Observe the shared memory stats via your ssh login. Verify that the Shmem and + ShmemHugePages values do not increase by more than 100MB even after 15 + minutes. + + [ Where problems could occur ] + + The Mesa fix affects all Gallium drivers that don't already set a memory + budget themselves. So it affects Intel graphics, but not (any/all?) + Radeon systems. If a code path existed that was relying on the previous + behaviour of never throttling uploads (and thus their OpenGL calls never + blocking) then new compositor bugs could arise in theory. + + The Mutter workaround (if applied) flushes OpenGL work to the GPU early + so can affect desktop performance in extreme cases with hundreds of + windows. Although it actually improves performance before that + threshold. The Mutter workaround could also interfere with the manual + command journalling that Cogl does internally for Mutter, resulting in + unpredictable graphics behaviour in the worst case. + + [ Original description ] + ShmemHugePages grows continuously while the screen is locked, consuming all 64GB RAM + 8GB swap, triggering the OOM killer. No single process accounts for the shmem — pages are orphaned in pagecache. Hardware — Lenovo ThinkPad 21QDCTO1WW, intel 225H CPU, with ARC 130T GPU. - Software — Ubuntu version, kernel 6.17.0-1012-oem, GNOME on Wayland, + Software — Ubuntu version, kernel 6.17.0-1012-oem, GNOME on Wayland, GPU driver version: Kernel driver in use: i915 - Kernel modules: i915, xe + Kernel modules: i915, xe Steps to reproduce — Log in to GNOME Wayland session, lock the screen, leave idle for 3-7 hours, observe ShmemHugePages in /proc/meminfo growing continuously - Evidence — Attach shmem_track.txt + Evidence — Attach shmem_track.txt The issue started post update to the 6.17.0-1012-oem. This has repeated multiple times over the last 3 days. The entire gnome session and, in some cases, even the psmouse driver got killed when I left the laptop untouched for hours. ProblemType: Bug DistroRelease: Ubuntu 24.04 Package: linux-oem-6.17-headers-6.17.0-1012 6.17.0-1012.12 ProcVersionSignature: Ubuntu 6.17.0-1012.12-oem 6.17.9 Uname: Linux 6.17.0-1012-oem x86_64 ApportVersion: 2.28.1-0ubuntu3.8 Architecture: amd64 CasperMD5CheckResult: pass CurrentDesktop: ubuntu:GNOME Date: Mon Mar 2 23:49:53 2026 InstallationDate: Installed on 2026-02-12 (18 days ago) InstallationMedia: Ubuntu 24.04.3 LTS "Noble Numbat" - Release amd64 (20250805.1) PackageArchitecture: all ProcEnviron: - LANG=en_US.UTF-8 - PATH=(custom, no user) - SHELL=/bin/bash - TERM=xterm-256color - XDG_RUNTIME_DIR=<set> + LANG=en_US.UTF-8 + PATH=(custom, no user) + SHELL=/bin/bash + TERM=xterm-256color + XDG_RUNTIME_DIR=<set> SourcePackage: linux-oem-6.17 UpgradeStatus: No upgrade log present (probably fresh install)
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2143073 Title: [i915] ShmemHugePages leak during GNOME lock screen To manage notifications about this bug go to: https://bugs.launchpad.net/gnome-shell/+bug/2143073/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
