Not a kernel bug. in fact this is a problem with the virtio graphics driver with 3d activated, and it is not related to kernel version. Reverting to non 3D graphics completely removes the problem. I am trying to work out which update caused this, but I doubt it is the kernel. In case this bug report comes up in search, the ontext is virt-manager and I have the kisak fresh mesa PPA (so not official 24.04 graphics stack, although point releases of Ubuntu move to newer mesa, so if it is a mesa bug it might be destined for 24.04 users anyway). I have tried latest upstream virt-manger (the client app) and the problem is the same.
On Thu, 11 Sept 2025 at 04:55, Alice C. Munduruca < [email protected]> wrote: > Hi Tim, > > From your description it seems like this problem only cropped up > recently, can you let us know the most recent known-good kernel version? > Running the following command would also help us get diagnostics info to > track down this bug. > > $ sudo apport-collect 2122372 > > Thanks for submitting the bug report! > > ** Also affects: linux (Ubuntu Noble) > Importance: Undecided > Status: New > > ** Changed in: linux (Ubuntu Noble) > Status: New => Incomplete > > ** Changed in: linux (Ubuntu) > Status: New => Incomplete > > -- > You received this bug notification because you are subscribed to the bug > report. > https://bugs.launchpad.net/bugs/2122372 > > Title: > 6.8 and 6.14 kernels massive shared memory bug > > To manage notifications about this bug go to: > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2122372/+subscriptions > > -- Tim Richardson -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2122372 Title: 6.8 and 6.14 kernels massive shared memory bug Status in linux package in Ubuntu: Incomplete Status in linux source package in Noble: Incomplete Bug description: This is a place holder report, I will add more information as time permits, mostly I want to see if this is recognised by others. I have an Ubuntu 24.04 VM on 24.04 host, AMD 64, 64 GB. 20GB ram, 2GB swap file. Used for development: runs docker compose and JetBrains IDE mostly. Problem. For the last couple of weeks, massive amounts of shared memory are consumed. This leads to OOM and the kernel OOM killer activates usually killing the gnome session. The systemd oomd does nothing and reports nothing in journald. The trigger to the shared memory use is elusive, but seems to be any kind of activity, possibly terminal activity. Running docker compose will quickly consume the 16 Gbi of free memory I have after boot (more or less), but so does general use of the IDE. In typical use, I can get one to two hours before OOM kill with the 20GBi allocated and 2GBi swap. I was using swapspace; the swap file would grow to 8GBi but the kernel OOM kill came just the same. Good news: kernel OOM kills are really decisive now :) Observations: * Problem is not reproducible with mainline 6.16.4 or 6.16.5 kernels. I have been doing normal activity, and shared memory is < 1 GBi. By now with an ubuntu kernel, it would be many GBi. (and thank goodness for this) * Old versions of the IDE have the same problem. It is not a regression in PyCharm. Also, it happens outside of the IDE. * No diagnostic tool known to an LLM can find the process behind the shared memory consumption. I have no actual proof of what is causing it. My suspicious is writing output to terminals, but nothing I do could account for GBs (scroll backlines were 10K now 1K, no difference) * it is never handed back by closing any process or app. It is orphaned. It continues to grow. * it is a hard, kernel recognised memory allocation which the kernel can not reclaim (until I log out). It causes swap exhaustion and then OOM killing, every time. * merely logging out releases all the shared memory. So it belongs to the user and user cgroup slice, I guess. * is the wayland gnome session Initially huge pages were used for the guest, but in troubleshooting as I removed them, the problem didn't change To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2122372/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
