On Tue, Jun 30, 2015 at 04:31:15PM +0100, Chris Wilson wrote: > That suggests MAP_FIXED is special in invalidating the range unlike a > normal mmap(). This is arguing that we must always make any access after > invalidate_range be EFAULT. The danger here is that I am not sure if there > are any circumstances where invalidate_range is called and the vma > survives. Looking again at mm/, I can't see any place where we can > legally be expecting to reuse the same address for a userptr after the > invalidate.
Sigh, changing page protections (e.g. after a fork) if I am not mistaken also generates an invalidate_range. Back to the drawing board here I am afraid, as I think I need a worker to do cancel_userptr with all the complications of coordinating between the multiple workers. -Chris -- Chris Wilson, Intel Open Source Technology Centre -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
