Looking at the blocking bugs and the waterfall, it looks like `adb devices` is failing on these hosts:

build110-b4
build106-b4
build109-b4

Also getting an offline device in device_status_check for:
build129-b4

Can infra labs take a look?

Thanks :)

I'll take a look at these as soon as I get to the lab.

A link to the failures would be very useful in the future.

build106-b4.  Device provisioned correctly on next build.  https://uberchromegw.corp.google.com/i/tryserver.chromium.perf/builders/android_nexus5_perf_bisect/builds/4276

build109-b4:  This one is odd.  The Device recovery step blacklists it as missing yet it is listed in the lsusb probes in that step.  I see it with adb. Let's see what happens with the next build.

chrome-bot@build109-b4:(Linux 14.04):~$ ./adb devices
List of devices attached
ZX1G22P3ZD	device
 
build110-b4:  usb hub that device is connected to was detached from the host for some reason.  It's back now.

chrome-bot@build110-b4:(Linux 14.04):~$ ./adb devices
List of devices attached
AG860440I4EI4GC device


build129-b4: In https://uberchromegw.corp.google.com/i/tryserver.chromium.perf/builders/android_nexus5X_perf_bisect/builds/791 it does 2 device_status steps and passes and then runs a third one and marks them both as offline.   Not sure what to make of this.  

chrome-bot@build126-b4:(Linux 14.04):~$ ./adb devices
List of devices attached
00b2322f5160926b	device
00be48d75190ae6a	device

Thanks for looking into this. I'll be more explicit about the failure links in future - however you should be able to find them in the blocked issues.