diff --git a/tests/run_tests.py b/tests/run_tests.py
index 018264d..5c10f6d 100755
--- a/tests/run_tests.py
+++ b/tests/run_tests.py
@@ -591,7 +591,7 @@ def functional_tests():
         do_test("mremap-expand-slice-collision.sh")
         do_test("mremap-fixed-normal-near-huge.sh")
         do_test("mremap-fixed-huge-near-normal.sh")
-    do_shm_test("shm-perms", 64*1024*1024)
+    do_shm_test("shm-perms", 1024*1024*1024)
 
     # Tests requiring an active mount and hugepage COW
     do_test("private")
diff --git a/tests/shm-perms.c b/tests/shm-perms.c
index 590a101..12d7609 100644
--- a/tests/shm-perms.c
+++ b/tests/shm-perms.c
@@ -32,7 +32,7 @@
 	"* to a segment with different permissions.  A segment is created  *\n"\
 	"* and children attach read-only to check reservation accounting.  *"
 
-#define SEGMENT_SIZE	((size_t)0x4000000)
+#define SEGMENT_SIZE	((size_t)0x40000000)
 #define SEGMENT_KEY	0x82ba15ff
 #define STRIDE		0x200000