An update: The problem I reported in January went away on its own after a few weeks of having the problem every single day when I booted each morning. I was installing Ubuntu software updates when they became available during that time. There is something going on during boot that causes this problem.
"my speculation" is that I suspect a timing issue with the way things are initialized during boot up that leads to the problem. Some strange timing issue is occurring which causes systemd-udevd to fall into an infinite loop (continuously looking for something or to be notified about an action completion) and drive one of the processor cores to 100%. When a new kernel was installed or something was done to change initialization activity during boot the problem went away because the timing problem that created it was changed. I believe that some kind of race condition may be at the root of the problem. >From my earlier search on the problem symptoms, it seems that when systemd-udevd isn't working correctly you can get numerous confusing symptoms that mysteriously go away when the something changes timing conditions during boot. Since the problem is in the kernel then it effects other systems besides Ubuntu. -- 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/1788018 Title: udevd keeps binding and unbinding some usb device und uses all cpu Status in Linux: Confirmed Status in linux package in Ubuntu: Incomplete Bug description: It first appeared when I upgraded ubuntu studio to 18.04 udevd started to use all available cpu. now I'm running ubuntu desktop from a usb key and it's still the same udevadm monitor returns: KERNEL[2512.539491] unbind /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.1/1-1.1.2/1-1.1.2:1.0 (usb) UDEV [2512.540201] bind /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.1/1-1.1.2/1-1.1.2:1.0 (usb) KERNEL[2512.566574] bind /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.1/1-1.1.2/1-1.1.2:1.0 (usb) KERNEL[2512.566866] unbind /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.1/1-1.1.2/1-1.1.2:1.0 (usb) UDEV [2512.567499] unbind /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.1/1-1.1.2/1-1.1.2:1.0 (usb) KERNEL[2512.594050] bind /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.1/1-1.1.2/1-1.1.2:1.0 (usb) KERNEL[2512.594310] unbind /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.1/1-1.1.2/1-1.1.2:1.0 (usb) UDEV [2512.596510] bind /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.1/1-1.1.2/1-1.1.2:1.0 (usb) KERNEL[2512.620736] bind /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.1/1-1.1.2/1-1.1.2:1.0 (usb) KERNEL[2512.624606] unbind /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.1/1-1.1.2/1-1.1.2:1.0 (usb) UDEV [2512.634706] unbind /devices/pci0000:00/0000:00:1a.0/usb1/1-1/1-1.1/1-1.1.2/1-1.1.2:1.0 (usb) ... WORKAROUND: Remove file: /lib/udev/rules.d/97-hid2hci.rules ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: udev 237-3ubuntu10.3 ProcVersionSignature: Ubuntu 4.15.0-29.31-generic 4.15.18 Uname: Linux 4.15.0-29-generic x86_64 ApportVersion: 2.20.9-0ubuntu7.2 Architecture: amd64 CasperVersion: 1.394 CustomUdevRuleFiles: 70-snap.core.rules Date: Mon Aug 20 18:54:48 2018 ExecutablePath: /lib/systemd/systemd-udevd LiveMediaBuild: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725) MachineType: Dell Inc. Vostro 3300 ProcEnviron: LANG=C.UTF-8 PATH=(custom, no user) ProcKernelCmdLine: file=/cdrom/preseed/hostname.seed boot=casper initrd=/casper/initrd.lz quiet splash --- maybe-ubiquity SourcePackage: systemd UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 02/10/2010 dmi.bios.vendor: Dell Inc. dmi.bios.version: A01 dmi.board.name: 07JC8T dmi.board.vendor: Dell Inc. dmi.board.version: A00 dmi.chassis.type: 8 dmi.chassis.vendor: Dell Inc. dmi.chassis.version: Not Specified dmi.modalias: dmi:bvnDellInc.:bvrA01:bd02/10/2010:svnDellInc.:pnVostro3300:pvrNotSpecified:rvnDellInc.:rn07JC8T:rvrA00:cvnDellInc.:ct8:cvrNotSpecified: dmi.product.name: Vostro 3300 dmi.product.version: Not Specified dmi.sys.vendor: Dell Inc. To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1788018/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
