1 files changed, 34 insertions, 0 deletions
diff --git a/tools/objtool/tests/generic/test-function-removal.sh b/tools/objtool/tests/generic/test-function-removal.sh
new file mode 100755
index 000000000000..df76e81e3936
--- /dev/null
+++ b/tools/objtool/tests/generic/test-function-removal.sh
@@ -0,0 +1,34 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# A patch which deletes a function leaves a symbol in the original with no
+# counterpart in the patched object.  klp diff cannot correlate it, and must
+# say so and carry on: livepatching cannot remove code from a running kernel,
+# so what matters is that the surviving caller is patched and the deleted
+# function is not dragged into the patch module.
+#
+# Cloning it would be worse than useless -- dead code in the patch, plus
+# whatever it references, resolved against a kernel where it may not exist.
+
+. "$(dirname "$0")/../lib.sh"
+
+setup
+build_pair function_removal.c
+
+# One-sided by construction: present in the original, gone from the patched.
+has_input_symbol orig.o going_away ||
+	fail "fixture has no going_away in the original"
+has_input_symbol patched.o going_away &&
+	fail "fixture still has going_away in the patched object"
+
+run_diff
+
+assert_diff_log 'no correlation: going_away'
+
+# The caller changed, so it is patched ...
+assert_patched caller
+# ... and the deleted function comes along in no form at all.
+assert_not_patched going_away
+assert_no_symbol going_away
+
+pass "deleted function reported as uncorrelated and left out of the patch"