On Mon, 1 Feb 2010, Al Viro wrote: > > Ehh... RCU will save you from stepping on freed memory, but it still will > leave the joy of half-updated string with length out of sync with it, etc. Sure. But do we care? Every printk _should_ be on a dentry that we have a reference to, anyway. Otherwise, how did we find it? So yeah, then there is the race with rename(), but (a) it's not going to happen, (b) if we race with rename there is no "one" correct solution anyway, so (c) what we really want to protect against is the printk causing problems (like an oops from DEBUG_PAGEALLOC and freeing the old name). > We probably can get away with that, but we'll have to be a lot more careful > with the order of updating these suckers in d_move_locked et.al. I wouldn't worry about it too much. So what if we get a screwed up name? If we use "%.*s" to print the name, we know that we won't overstep the old name even if the NUL termination somehow went away (because we're busy copying a new, longer, name over it or whatever). So I would not worry too much about sometimes showing a nonsensical name that may be the result of a concurrent rename. I'd only worry about it not oopsing or stepping on memory that hasn't had _either_ the old or the new name in it. That's why I think an RCU solution should be sufficient.. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
