On Wed, 5 Jul 2017 20:28:49 +0200 Michal Hocko <mho...@kernel.org> wrote:
> "mm: enlarge stack guard gap" has introduced a regression in some rust > and Java environments which are trying to implement their own stack > guard page. They are punching a new MAP_FIXED mapping inside the > existing stack Vma. > > This will confuse expand_{downwards,upwards} into thinking that the stack > expansion would in fact get us too close to an existing non-stack vma > which is a correct behavior wrt. safety. It is a real regression on > the other hand. Let's work around the problem by considering PROT_NONE > mapping as a part of the stack. This is a gros hack but overflowing to > such a mapping would trap anyway an we only can hope that usespace > knows what it is doing and handle it propely. > > Fixes: d4d2d35e6ef9 ("mm: larger stack guard gap, between vmas") That should be 1be7107fbe18, yes? > Debugged-by: Vlastimil Babka <vba...@suse.cz> > Signed-off-by: Michal Hocko <mho...@suse.com>