Thanks Dan. About cgmanager: if we don't have it installed, it does not affect memory of systemd-logind tool per se. What happens, IMHO, is even more severe: we don't free/de-allocate sysfs cgroup paths for sessions. So, in my tests _without_ cgmanager, after 8000 SSH sessions to my target machine, I found 8000 folders with some files each at /sys/fs/cgroup/systemd/user/<my_user>/ .
Although it doesn't directly affects systemd-logind memory footprint, it certainly affects system memory overall. So, in my consideration (given cgmanager has even code glue added to systemd on Trusty), I'd suggest to make it a dependency, not sure why it isn't anyway - for me, this cgroup folders' leak is clearly a bug. -- You received this bug notification because you are a member of STS Sponsors, which is subscribed to the bug report. https://bugs.launchpad.net/bugs/1750013 Title: systemd-logind: memory leaks on session's connections (trusty-only) Status in systemd package in Ubuntu: Fix Released Status in systemd source package in Trusty: In Progress Status in systemd source package in Xenial: Fix Released Status in systemd source package in Artful: Fix Released Status in systemd source package in Bionic: Fix Released Bug description: Below the SRU request form. Please refer to the Original Description to a more comprehensive explanation of the problem observed. [Impact] * systemd-logind tool is leaking memory at each session connected. The issues happens in systemd from Trusty (14.04) only. * Three issues observed: - systemd-logind is leaking entire sessions, i.e, the sessions are not feeed after they're closed. In order to fix that, we proactively add the sessions to systemd garbage collector (gc) when they are closed. Also, part of the fix is to make cgmanager package a dependency. Refer to comment #1 to a more thorough explanation of the issue and the fix. - a small memory leak was observed in the session creation logic of systemd-logind. The fix for that is the addition of an appropriate free() call. Refer to comment #2 to more details on the issue and fix. - another small memory leak was observed in the cgmanager glue code of systemd-logind - this code is only present in this specific Ubuntu release of the package, due to necessary compatibility layer with upstart init system. The fix is to properly call free() in 2 functions. Refer to comment #3 to a deep exposition of the issue and the fix. [Test Case] * The basic test-case is to run the following loop from a remote machine: while true; do ssh <hostname-target> "whoami"; done * It's possible to watch the increase in memory consumption from "systemd-logind" process in the target machine. One can use the "ps uax" command to verify the RSS of the process, or count its anonymous pages from /proc/<logind_pid>/smaps. [Regression Potential] * Since the fixes are small and not intrusive, the potential for regressions are low. More regression considerations on comments #1, #2 and #3 for each fix. * A potential small regressson is performance-wise, since now we add sessions to garbage collector proactively. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1750013/+subscriptions -- Mailing list: https://launchpad.net/~sts-sponsors Post to : sts-sponsors@lists.launchpad.net Unsubscribe : https://launchpad.net/~sts-sponsors More help : https://help.launchpad.net/ListHelp
