[PATCH 3.17 076/122] of/selftest: Fix off-by-one error in removal path

[Greg Kroah-Hartman]

3.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Grant Likely <grant.likely@xxxxxxxxxx>

commit c1a2086e2d8c4eb4e8630ba752e911ec180dec67 upstream.

The removal path for selftest data has an off by one error that causes
the code to dereference beyond the end of the nodes[] array on the first
pass through. The old code only worked by chance on a lot of platforms,
but the bug was recently exposed on aarch64.

The fix is simple. Decrement the node count before dereferencing, not
after.

Reported-by: Kevin Hilman <khilman@xxxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Gaurav Minocha <gaurav.minocha.os@xxxxxxxxx>

---
 drivers/of/selftest.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/of/selftest.c
+++ b/drivers/of/selftest.c
@@ -799,7 +799,7 @@ static void selftest_data_remove(void)
 		return;
 	}
 
-	while (last_node_index >= 0) {
+	while (last_node_index-- > 0) {
 		if (nodes[last_node_index]) {
 			np = of_find_node_by_path(nodes[last_node_index]->full_name);
 			if (strcmp(np->full_name, "/aliases") != 0) {
@@ -812,7 +812,6 @@ static void selftest_data_remove(void)
 				}
 			}
 		}
-		last_node_index--;
 	}
 }
 


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