[PATCH 5.10 152/167] nds32: fix up stack guard gap

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

commit c453db6cd96418c79702eaf38259002755ab23ff upstream.

Commit 1be7107fbe18 ("mm: larger stack guard gap, between vmas") fixed
up all architectures to deal with the stack guard gap.  But when nds32
was added to the tree, it forgot to do the same thing.

Resolve this by properly fixing up the nsd32's version of
arch_get_unmapped_area()

Cc: Nick Hu <nickhu@xxxxxxxxxxxxx>
Cc: Greentime Hu <green.hu@xxxxxxxxx>
Cc: Vincent Chen <deanbo422@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Qiang Liu <cyruscyliu@xxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Reported-by: iLifetruth <yixiaonn@xxxxxxxxx>
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210629104024.2293615-1-gregkh@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 arch/nds32/mm/mmap.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/nds32/mm/mmap.c
+++ b/arch/nds32/mm/mmap.c
@@ -59,7 +59,7 @@ arch_get_unmapped_area(struct file *filp
 
 		vma = find_vma(mm, addr);
 		if (TASK_SIZE - len >= addr &&
-		    (!vma || addr + len <= vma->vm_start))
+		    (!vma || addr + len <= vm_start_gap(vma)))
 			return addr;
 	}