Add the missing SPDX-License-Identifier tag to
recursion-depth.c . The file uses the ISC License
 as indicated by the existing license text in the
 file header.

Signed-off-by: Joyeta Modak <joyetamdk@gmail.com>
---
 tools/testing/selftests/exec/recursion-depth.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/exec/recursion-depth.c b/tools/testing/selftests/exec/recursion-depth.c
index 7b5c4f6d1928..a6c42a9b22d7 100644
--- a/tools/testing/selftests/exec/recursion-depth.c
+++ b/tools/testing/selftests/exec/recursion-depth.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: ISC
 /*
  * Copyright (c) 2019 Alexey Dobriyan <adobriyan@gmail.com>
  *
-- 
2.53.0