On Wed 24-05-17 23:07:30, Wei Yang wrote: > On Wed, May 24, 2017 at 02:11:35PM +0200, Michal Hocko wrote: > >On Wed 24-05-17 18:03:47, Wei Yang wrote: > >> The vmap RB tree store the elements in order and no overlap between any of > >> them. The comparison in __insert_vmap_area() is to decide which direction > >> the search should follow and make sure the new vmap_area is not overlap > >> with any other. > >> > >> Current implementation fails to do the overlap check. > >> > >> When first "if" is not true, it means > >> > >> va->va_start >= tmp_va->va_end > >> > >> And with the truth > >> > >> xxx->va_end > xxx->va_start > >> > >> The deduction is > >> > >> va->va_end > tmp_va->va_start > >> > >> which is the condition in second "if". > >> > >> This patch changes a little of the comparison in __insert_vmap_area() to > >> make sure it forbids the overlapped vmap_area. > > > >Why do we care about overlapping vmap areas at this level. This is an > >internal function and all the sanity checks should have been done by > >that time AFAIR. Could you describe the problem which you are trying to > >fix/address? > > > > No problem it tries to fix. I would prefer the not touch the code if there is no problem to fix. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
