The problem is still present in 3.19.0-42-generic kernel. After bisecting code, I've found that problem was introduced by 06ec92f3bac598a7a9b9ecf451ab1915929a5980 commit - http://kernel.ubuntu.com/git/ubuntu/ubuntu-vivid.git/commit/?id=06ec92f3bac598a7a9b9ecf451ab1915929a5980
The problem is still present in 3.19.0-42-generic kernel. 7a9b9ecf451ab19 15929a5980 commit - http:// kernel. ubuntu. com/git/ ubuntu/ ubuntu- vivid.git/ commit/ ?id=06ec92f3bac 598a7a9b9ecf451 ab1915929a5980
After bisecting code, I've found that problem was introduced by 06ec92f3bac598a