Comment 0 for bug 1485057

reproducible: always

Steps to reproduce:
- open a terminal
- sudo bash
- lsusb -v

In a virtual terminal, the command prints the name of the first device it finds, then the system freezes completely. In a terminal of the desktop, I don't even get the name of the device, the system freezes immediately. Either way, I have to power off the machine. There is no kernel oops. Nothing is written to the log. The magic sysreq key yields no response, although I have verified that it works before triggering the freeze.

I've narrowed down the problem by calling "lsusb -v -s <device>". The system freezes on both devices of bus 3 (003:001 and 003:002). For all other devices, it prints the expected output and continues to work. When calling lsusb as a regular user, I get "Couldn't open device, some information will be missing", then the regular output, and the system keeps running. Therefore I assume that the problem is somewhere in the kernel, when the devices are accessed.

This is a regression. It used to work in 14.10, and fails to work since 15.04.
It also used to work in 14.04.2, and fails in 14.04.3.
It fails with mainline builds 4.2.0-rc6-unstable, 4.2.0-rc2-unstable, 4.1.0-rc2-vivid. (yeah, I've been trying for a while :-)

Incidentally, the shutdown sequence also freezes early on with the kernels that exhibit the problem; but I cannot be sure that the cause is the same. I decided to first chase the USB freeze, because it was easier to gather information about that.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: linux-image-3.19.0-25-generic 3.19.0-25.26
ProcVersionSignature: Ubuntu 3.19.0-25.26-generic 3.19.8-ckt2
Uname: Linux 3.19.0-25-generic x86_64
ApportVersion: 2.17.2-0ubuntu1.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: rweber 1525 F.... pulseaudio
CurrentDesktop: XFCE
Date: Fri Aug 14 18:38:36 2015
HibernationDevice: RESUME=UUID=8a45266d-0232-428e-bb25-113d23caaf8a
InstallationDate: Installed on 2015-06-28 (46 days ago)
InstallationMedia: Xubuntu 14.10 "Utopic Unicorn" - Release amd64 (20141022.1)
MachineType: Acer Aspire ES1-111M
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.19.0-25-generic root=UUID=b8872e03-7295-4cbd-ac86-06b9be2f112f ro quiet splash crashkernel=384M-:128M vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.19.0-25-generic N/A
 linux-backports-modules-3.19.0-25-generic N/A
 linux-firmware 1.143.3
SourcePackage: linux
UpgradeStatus: Upgraded to vivid on 2015-07-05 (39 days ago)
dmi.bios.date: 08/20/2014
dmi.bios.vendor: Insyde Corp.
dmi.bios.version: V1.08
dmi.board.asset.tag: Type2 - Board Asset Tag
dmi.board.name: R2
dmi.board.vendor: Acer
dmi.board.version: Type2 - A01 Board Version
dmi.chassis.type: 10
dmi.chassis.vendor: Chassis Manufacturer
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnInsydeCorp.:bvrV1.08:bd08/20/2014:svnAcer:pnAspireES1-111M:pvrV1.08:rvnAcer:rnR2:rvrType2-A01BoardVersion:cvnChassisManufacturer:ct10:cvrChassisVersion:
dmi.product.name: Aspire ES1-111M
dmi.product.version: V1.08
dmi.sys.vendor: Acer