On Wed, Oct 23, 2019 at 12:27:36PM +0200, Michal Hocko wrote: > From: Michal Hocko <mhocko@xxxxxxxx> > > /proc/pagetypeinfo is a debugging tool to examine internal page > allocator state wrt to fragmentation. It is not very useful for > any other use so normal users really do not need to read this file. > > Waiman Long has noticed that reading this file can have negative side > effects because zone->lock is necessary for gathering data and that > a) interferes with the page allocator and its users and b) can lead to > hard lockups on large machines which have very long free_list. > > Reduce both issues by simply not exporting the file to regular users. > > Reported-by: Waiman Long <longman@xxxxxxxxxx> > Cc: stable > Signed-off-by: Michal Hocko <mhocko@xxxxxxxx> Acked-by: Mel Gorman <mgorman@xxxxxxx> -- Mel Gorman SUSE Labs
