Update: I take it back: it's not just model uploads. SL crashes when trying to upload anything right now. 220.127.116.116094 on OS X 10.10.1. Crashes every time.
I find it interesting that the question is specifically "crashing when trying to upload" and the answers are talking about DNS and connecting to second life.
Well, in my case, let me make it clear:
I have the same crashing of Second Life 18.104.22.1686094 on OS X 10.10.1 anytime I try to upload a model exported from Blender 2.72b using the Second Life and Open Sim static presets on the Collada exporter.
To be clear: Second Life just completely crashes as soon as the model import options dialog appears in Second Life. This is a crash, it's not a DNS issue or trying to download anything.
Anyone else see this?