Comment 110 for bug 93546

It should be possible to test for broken NFS locking somehow. Are there really still a significant number of broken NFS implementations out there? In any case you could use alternate (albeit less efficient) locking mechanisms if necessary.

Realistically I don't think finding a locking mechanism is the biggest problem. I'd think it would take a massive code review to identify all the places where the code assumes it has exclusive access to the profile, and there are likely to be cases that require major changes to fix. (Remember we're not just talking about preferences and bookmarks here, it's also the cache, extensions, and I don't know what else.)