UserAgent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36

Steps to reproduce the problem:
Start webRTC audio call:
1. create peer connection
2. get user media (mic) and add input stream to peer connection
3. create offer SDP, set it as local description and send it to remote peer
4. get answer SDP from remote peer and set it as remote description
5. exchange ICE candidates
6. media (ICE) is connected

Freeze might happen at any phase of the call setup, until the media is connected

What is the expected behavior?

What went wrong?
We have reports from our users that Chrome intermittently freezes for a few seconds when starting a WebRTC call. These freezes last for 10-20s and affect all Chrome windows and tabs (all of them are unresponsive), while other Windows applications (and Windows itself) are running fine. After these 10-20s they start responding again, but the freeze make our WebRTC call fail.
I was able to reproduce a 10s freeze and I had Chrome logs enabled when it happened (see attached chrome_debug.log). The freeze happened between 10:52:58 and 10:53:08 (Oct 26th, 2017).
The WebRTC call didn't fail in this case, but the freeze should be the same our users are experiencing. It's very hard to reproduce it in Lab, so that's the closest we could get to it.
Any help would be highly appreciated. Thanks!

Did this work before? N/A 

Chrome version: 61.0.3163.100  Channel: n/a
OS Version: 6.1 (Windows 7, Windows Server 2008 R2)
Flash Version: 27.0.0.183
 

Deleted: chrome_debug.log 7.4 MB

chrome_debug.log 7.4 MB View Download