Knowing that --no-drop-privileges is related I was breaking that into sub-sections.
I set -O0 for better debugging. Then I dropped code of the drop-priv section. This section is it: 1755 if (setgroups(0, NULL) < 0 || 1756 setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) < 0 || 1757 setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) < 0) { 1758 r = -errno; 1759 syslog(LOG_ERR, "Failed to become %s: %s\n", username, strerror(errno)); 1760 return r; 1761 } All three work: __GI_setgroups (n=0, groups=0x0) __GI___setresgid (rgid=114, egid=114, sgid=114) __GI___setresuid (ruid=109, euid=109, suid=109) IDs match: $ id 109 uid=109(rtkit) gid=114(rtkit) groups=114(rtkit) So it is actually indeed user-related like https://bbs.archlinux.org/viewtopic.php?id=230079 was. I see no difference in the user in my test system vs the failing one. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to rtkit in Ubuntu. https://bugs.launchpad.net/bugs/1871543 Title: rtkit fails to start in focal "pthread_create failed: Resource temporarily unavailable" Status in rtkit package in Ubuntu: New Bug description: I was debugging something else and found rtkit broken on my system. Apr 08 06:09:22 Keschdeichel rtkit-daemon[1726502]: Successfully called chroot. Apr 08 06:09:22 Keschdeichel rtkit-daemon[1726502]: Successfully dropped privileges. Apr 08 06:09:22 Keschdeichel rtkit-daemon[1726502]: Successfully limited resources. Apr 08 06:09:22 Keschdeichel rtkit-daemon[1726502]: pthread_create failed: Resource temporarily unavailable Apr 08 06:09:22 Keschdeichel rtkit-daemon[1726502]: Canary thread running. Apr 08 06:09:22 Keschdeichel rtkit-daemon[1726502]: Exiting canary thread. Apr 08 06:09:22 Keschdeichel rtkit-daemon[1726502]: Demoting known real-time threads. Apr 08 06:09:22 Keschdeichel rtkit-daemon[1726502]: Demoted 0 threads That state is reproducible through restarts. I haven't looked any further yet. ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: rtkit 0.12-4 ProcVersionSignature: Ubuntu 5.3.0-45.37~18.04.1-generic 5.3.18 Uname: Linux 5.3.0-45-generic x86_64 NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair ApportVersion: 2.20.11-0ubuntu24 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Wed Apr 8 07:59:58 2020 InstallationDate: Installed on 2018-10-12 (543 days ago) InstallationMedia: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725) SourcePackage: rtkit UpgradeStatus: Upgraded to focal on 2020-04-03 (4 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/rtkit/+bug/1871543/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp