The .12 → .13 regression window reported here matches a specific patch. mutter 46.2-1ubuntu0.24.04.13 (2025-12-03) carries:
* d/p: Make sure the monitor is powered off when screen blanks (LP: #1971434) That patch exposes this leak. Before .13, idle blank left the external monitor powered on; from .13 the monitor is put into DPMS-off; the DPMS-off transition starts the ~8.5s MonitorsChanged loop (with xdg-desktop-portal-gnome logging "Monitor 'Built-in display' has no configuration which is-current!" once per cycle), stranding ~2 framebuffer-sized DMA-BUFs (~32MB each at 4K) inside gnome-shell per cycle — ~0.5GB/min, released only by a gnome-shell restart, and invisible to the OOM killer. Three lines of evidence converge on that patch: 1. Michael Nahas, above: 46.2-1ubuntu0.24.04.12 clean for 20 days; OOM returned after upgrading to .13. 2. Paul Phillips, above: reproduced on Intel Lunar Lake with 7.0.0-28-generic (linux-image-generic-hwe-24.04) on mutter .14 and .16 — so this is specific to neither Arrow Lake nor the OEM kernel. 3. Locally: suppressing the DPMS-off is sufficient to stop the leak entirely. A guard that forces org.gnome.Mutter.DisplayConfig PowerSaveMode back to 0 whenever it goes non-zero — effectively a runtime revert of the LP #1971434 behavior — has held gnome-shell flat at 94 exported DMA-BUF fds / ~5.5GB drm-total-gtt across a 16-day session, on the same clamshell + external-HDMI setup that previously OOMed within ~45 minutes of a screen blank. The unreleased buffer in the MonitorsChanged path is the real bug. But the LP #1971434 patch exposes it to every clamshell / external-monitor user on noble, and it is an SRU into a stable release. Worth considering a revert, or a setting to opt out of DPMS-off on blank, until the leak is fixed. -- 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: ShmemHugePages leak during GNOME lock screen on 6.17.0-1012-oem causes OOM To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/2143073/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
