[Bug 1759836]

[sobik.szymon]

I use ubuntu 18.04 with 4.15 kernel
I have hit the same problem, but with synaptics touchpad.

I have bisected 4.13-4.14 and the problem was in commit
1455cf8dbfd06aa7651dcfccbadb7a093944ca65 (as in the attached patch)

I am unable to use USB bus because udev is bogged down with these
bind/unbind events

```
UDEV  [496.168312] bind     /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4.2/2-1.4.2:1.0 (usb)
KERNEL[496.175932] bind     /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4.2/2-1.4.2:1.0 (usb)
KERNEL[496.176947] unbind   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4.2/2-1.4.2:1.0 (usb)
UDEV  [496.177602] unbind   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4.2/2-1.4.2:1.0 (usb)
KERNEL[496.185259] bind     /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4.2/2-1.4.2:1.0 (usb)
KERNEL[496.185479] unbind   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4.2/2-1.4.2:1.0 (usb)
UDEV  [496.186342] bind     /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4.2/2-1.4.2:1.0 (usb)
KERNEL[496.196813] bind     /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4.2/2-1.4.2:1.0 (usb)
KERNEL[496.197103] unbind   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4.2/2-1.4.2:1.0 (usb)
UDEV  [496.197501] unbind   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4.2/2-1.4.2:1.0 (usb)
KERNEL[496.207283] bind     /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4.2/2-1.4.2:1.0 (usb)
```

```
> cat /sys/bus/usb/devices/2-1.4/2-1.4.2/id*
8162
413c
```

```
> lsusb -d 413c:8162
Bus 002 Device 006: ID 413c:8162 Dell Computer Corp. Integrated Touchpad [Synaptics]
```

-- 
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Foundations Bugs, which is subscribed to systemd in Ubuntu.
https://bugs.launchpad.net/bugs/1759836

Title:
  systemd-udevd consumes 100% of CPU

Status in linux:
  Confirmed
Status in The Ubuntu Power Consumption Project:
  New
Status in bluez package in Ubuntu:
  Invalid
Status in linux package in Ubuntu:
  Incomplete
Status in systemd package in Ubuntu:
  Confirmed

Bug description:
  The systemd-udevd proccess consumes 100% of a thread everytime, but
  i'm not noticing any difference in my computer.

  ProblemType: Bug
  DistroRelease: Ubuntu 18.04
  Package: systemd 237-3ubuntu6
  ProcVersionSignature: Ubuntu 4.15.0-13.14-generic 4.15.10
  Uname: Linux 4.15.0-13-generic x86_64
  NonfreeKernelModules: wl
  ApportVersion: 2.20.9-0ubuntu2
  Architecture: amd64
  CurrentDesktop: ubuntu:GNOME
  Date: Thu Mar 29 08:52:54 2018
  InstallationDate: Installed on 2018-03-05 (23 days ago)
  InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180304)
  MachineType: Dell Inc. Inspiron N5010
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-13-generic root=UUID=3c29e292-f1ae-45e1-a0ed-a82524278ce1 ro quiet splash vt.handoff=1
  SourcePackage: systemd
  SystemdDelta:
   [EXTENDED]   /lib/systemd/system/rc-local.service → /lib/systemd/system/rc-local.service.d/debian.conf
   [EXTENDED]   /lib/systemd/system/user at .service → /lib/systemd/system/user at .service.d/timeout.conf

   2 overridden configuration files found.
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 01/25/2011
  dmi.bios.vendor: Dell Inc.
  dmi.bios.version: A12
  dmi.board.name: 08R0GW
  dmi.board.vendor: Dell Inc.
  dmi.board.version: A12
  dmi.chassis.type: 8
  dmi.chassis.vendor: Dell Inc.
  dmi.chassis.version: A12
  dmi.modalias: dmi:bvnDellInc.:bvrA12:bd01/25/2011:svnDellInc.:pnInspironN5010:pvrA12:rvnDellInc.:rn08R0GW:rvrA12:cvnDellInc.:ct8:cvrA12:
  dmi.product.name: Inspiron N5010
  dmi.product.version: A12
  dmi.sys.vendor: Dell Inc.

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