On Fri 28-06-19 10:46:28, Alastair D'Silva wrote: [...] > Given that there is already a VM_BUG_ON in the code, how do you feel > about broadening the scope from 'VM_BUG_ON(!root)' to 'VM_BUG_ON(!root > || (root_nr == NR_SECTION_ROOTS))'? As far as I understand the existing VM_BUG_ON will hit when the mem_section tree gets corrupted. This is a different situation to an incorrect section given so I wouldn't really mix those two. And I still do not see much point to protect from unexpected input parameter as this is internal function as already pointed out. -- Michal Hocko SUSE Labs