Avoid segfaults in j9vmem_testOverlappingSegments

Since the keepCycles array is zero-initialized, if the test is aborted
in the very first cycle (i == 0) the cleanup procedure at the end cannot
rely on the fact that keepCycles[j] >= i implies that segment j must
be freed. Before these changes, such a scenario would cause the test
to segfault during cleanup.

Signed-off-by: Christian Despres <[email protected]>

runtime/tests/port/j9vmemTest.c

@@ -3415,6 +3415,9 @@ j9vmem_testOverlappingSegments(struct J9PortLibrary *portLibrary)
 		if (NULL == memPtr) {
 			outputComment(PORTLIB, "Failed to get memory. Error: %s.\n", strerror(errno));
 			outputComment(PORTLIB, "Ignoring memory allocation failure(%d of %d loops finished).\n", i, CYCLES);
+			if (0 == i) {
+				keepCycles[0] = -1; /* This segment would otherwise look like it needed to be freed during cleanup */
+			}
 			goto exit;
 		}
 		/* Determine how long to keep the segment */
@@ -3457,7 +3460,8 @@ j9vmem_testOverlappingSegments(struct J9PortLibrary *portLibrary)
 
 	/* Free remaining segments */
 	freed = 0;
-	for (j = 0; j < CYCLES; j++) {
+	i = (CYCLES == i) ? i : i + 1;
+	for (j = 0; j < i; j++) {
 		if (keepCycles[j] >= i) {
 			I_32 rc = j9vmem_free_memory(vmemID[j].address, vmemParams[j].byteAmount, &vmemID[j]);
 			if (0 == rc) {