rockbox version 3.11.2
If I do a manual database update (settings -> database -> Update Now), [rockbox tells me the database will update in the background], then while the database is updating I go to main menu -> Plugins, then rockbox hangs. It seems unresponsive however disk is still spinning and seeking (rapidly). I can get the same hang if I go to main menu -> Database -> Recently Added . At a guess, it could be related to trying to access the disk while the database updater is accessing the disk - but if that's the case I'd be surprise if it's gone unnoticed before.
Note that dircache turns itself off (still? at least for me) when I go to settings -> database -> Update Now.
rockbox seems to be functioning fine usually, so long as database update isn't running