Some bugs are so deep the open source process can't fix them.
Some bugs are so deep that they are very difficult to fix. FTFY
Search Google for "prune_one_dentry oops". [...] nobody wants to take that on.
FUD. The fix is in the work for a long time. Christoph Lameter recently (01/29/2010) submitted the 15th iteration of the patch set. Hopefuly this time no unforeseen consequences will prevent it to be merged into the official kernel. You can read about it here: http://lkml.org/lkml/2010/1/29/332