Hi, I am running OS X 10.10.1 on a mid-2010 MacBook Pro (6,2). The last couple of months (not sure which Yosemite version it started in), I have experienced what seems like random crashes. When they occur, the computer restarts twice and any unsaved data is lost. I fail to identify any specific trigger the last time it happened in the middle of just reading a text-filled PDF in Safari, with Spotify in the background. The crash report is attached, can any wise interpreter guide me to the problem?