On Fri, Oct 26, 2018 at 03:17:07AM -0700, Matthew Wilcox wrote: > On Fri, Oct 26, 2018 at 11:32:05AM +0200, Peter Zijlstra wrote: > > On Wed, Oct 24, 2018 at 12:35:00AM +0300, Igor Stoppa wrote: > > > Some of the data structures used in list management are composed by two > > > pointers. Since the kernel is now configured by default to randomize the > > > layout of data structures soleley composed by pointers, this might > > > prevent correct type punning between these structures and their write > > > rare counterpart. > > > > 'might' doesn't really work for me. Either it does or it does not. > > He means "Depending on the random number generator, the two pointers > might be AB or BA. If they're of opposite polarity (50% of the time), > it _will_ break, and 50% of the time it _won't_ break." So don't do that then. If he were to include struct list_head inside his prlist_head, then there is only the one randomization and things will just work. Also, I really don't see why he needs that second type and all that type punning crap in the first place.
