Thread (69 messages) 69 messages, 2 authors, 21d ago

[PATCH v4 30/58] objtool/klp: Add test for Module.symvers path normalization

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From: Song Liu <song@kernel.org>
Date: 2026-09-15 23:37:43
Subsystem: objtool, the rest · Maintainers: Josh Poimboeuf, Peter Zijlstra, Linus Torvalds

Revision v4 of 5 in this series.

Revisions (5)
  1. v1 [diff vs current]
  2. v2 [diff vs current]
  3. v3 [diff vs current]
  4. v4 current
  5. v5 [diff vs current]
Module.symvers names an export's owner by build path, and the kernel knows
modules by their runtime name.  Without normalizing one to the other, an
export owned by a module is not recognised as owned by anything, and a
reference that should become a klp relocation stays an ordinary one.

This tests the behavior of commit 8668bf91e050 ("objtool/klp: Normalize
Module.symvers paths to module names").

Assisted-by: Claude:claude-opus-4
Based-on-test-by: Joe Lawrence [off-list ref]
Assisted-by: Claude:claude-opus-5
Signed-off-by: Song Liu <song@kernel.org>
---
 .../tests/generic/test-modname-normalize.sh   | 26 +++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100755 tools/objtool/tests/generic/test-modname-normalize.sh
diff --git a/tools/objtool/tests/generic/test-modname-normalize.sh b/tools/objtool/tests/generic/test-modname-normalize.sh
new file mode 100755
index 000000000000..a8059bdbd667
--- /dev/null
+++ b/tools/objtool/tests/generic/test-modname-normalize.sh
@@ -0,0 +1,26 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Module.symvers records the build-tree path of the object that exports a
+# symbol, not the name the module has at runtime: "arch/x86/kvm/kvm-intel",
+# where the kernel knows the module as "kvm_intel".
+#
+# The klp symbol name embeds the owning object, and livepatch matches it
+# against loaded modules by name.  Left unnormalized it names a module that
+# does not exist, and the relocation is never resolved -- at load time, with no
+# build-time complaint.
+
+. "$(dirname "$0")/../lib.sh"
+
+setup
+build_module_pair cross_module.c klp_testmod
+
+# A path with directory components, a dash, and no extension.
+export_syms
+add_exports "arch/x86/kvm/kvm-intel" other_mod_func
+run_diff
+
+# Directories stripped, dash to underscore.
+assert_klp_sym other_mod_func kvm_intel
+
+pass "Module.symvers paths normalized to runtime module names"
-- 
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