[PATCH v2 43/58] objtool/klp: Test rejection of a file-local static branch key

@@ -0,0 +1,45 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# A static branch key owned by a module is rejected whether the key is global
+# or file-local.
+#
+# The rejection matters because late module patching allows the livepatch
+# module to load before the module it depends on: the __jump_table klp reloc is
+# then unresolved, and jump_label_add_module() dereferences an uninitialized
+# pointer.  Catching it at build time is the only defence.
+#
+# test-jump-label-module-key covers the global key.  A file-local one reaches
+# the same check by a different route: the compiler emits the reference against
+# the section symbol plus an addend, so validate_special_section_klp_reloc()
+# has to resolve it to the underlying object before it can see a key at all.
+# Until it did, a static key was passed over as "not STT_OBJECT" and the
+# unsupported reference was emitted with nothing said.
+#
+# Fixed by f9fb44b0ecef ("objtool/klp: Fix detection of corrupt static
+# branch/call entries").
+
+. "$(dirname "$0")/../lib.sh"
+
+setup
+build_pair jump_label.c -DSTATIC_KEY -DMODNAME='"klp_testmod"'
+
+require_input_section __jump_table
+
+# The premise: the key is reached through its section symbol, not by name.
+# Without that this is just a second copy of test-jump-label-module-key.
+input_jump_relocs="$(in_relocs orig.o | awk '/rela__jump_table/,/^$/')"
+
+echo "$input_jump_relocs" | grep -q klp_test_key ||
+	fail "fixture produced no __jump_table reference to the key"
+echo "$input_jump_relocs" | grep -qE '\.(bss|data)\.klp_test_key' ||
+	probe_skip "compiler referenced the static key by name, not through its section"
+
+run_diff 255
+
+diff_log | grep -q 'unsupported static branch key klp_test_key' ||
+	fail "expected rejection, got: $(diff_log | tail -1)"
+[ -e "$workdir/out.o" ] &&
+	fail "output object produced for a rejected input"
+
+pass "module-owned file-local static branch key rejected"