Merge tag 'objtool-core-2026-10-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool updates from Ingo Molnar:

- Add unit test suite for objtool klp functionality and
known

Merge tag 'objtool-core-2026-10-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool updates from Ingo Molnar:

- Add unit test suite for objtool klp functionality and
known failure modes (by Song Liu and Puranjay Mohan,
with fixes by Joe Lawrence)

* tag 'objtool-core-2026-10-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (58 commits)
objtool/klp: Add test for ThinLTO symbols sharing a demangled name
objtool/klp: Add test for Clang switch jump tables
objtool/klp: Add test for UBSAN metadata in an unchanged function
objtool/klp: Add test for absolute and __ADDRESSABLE symbols
objtool/klp: Add test for a patch which strips a data annotation
objtool/klp: Add test for the alignment of cloned data sections
objtool/klp: Add test for alternative replacement code in checksums
objtool/klp: Add test for instruction operand checksums
objtool/klp: Add test for a static call introduced by the patch
objtool/klp: Add test for tracepoint and pr_debug static branch keys
objtool/klp: Add test for a static branch introduced by the patch
objtool/klp: Add test for symbols with no checksum entry of their own
objtool/klp: Add test for data object checksums
objtool/klp: Test text annotations on alternative replacements
objtool/klp: Test a hand-built livepatch module's static call keys
objtool/klp: Test rejection of a file-local static branch key
objtool/klp: Add test for symbols whose linkage the patch changes
objtool/klp: Add test for kCFI prefix symbols and traps
objtool/klp: Add test for __bug_table, __ex_table and __mcount_loc extraction
objtool/klp: Add test for static locals which must not be correlated
...

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objtool/klp: Test text annotations on alternative replacements

The kernel annotates instructions inside an ALTERNATIVE's replacement
wherever objtool has to be told something about them -- a retpoli

objtool/klp: Test text annotations on alternative replacements

The kernel annotates instructions inside an ALTERNATIVE's replacement
wherever objtool has to be told something about them -- a retpoline-safe
indirect branch, a deliberately absent ENDBR. klp diff dropped those
annotations, for two reasons: replacement code has no real symbol, so the
NOTYPE fake symbol objtool invents for it was not recognised as worth
keeping a reference to, and .discard.annotate_insn was processed before
.altinstructions, so the replacement it named had no clone yet.

Nothing fails at build time when the annotation goes missing. It surfaces
later as objtool warning about, or rejecting, the very code the annotation
was there to explain.

The fixture keeps the replacement label global, as empty_alternative.c
does, so the relocations name it instead of .altinstr_replacement plus an
addend -- which klp diff rejects outright. The label is still NOTYPE,
which is the property under test. The test asserts the relocation as well
as the section, since an entry whose relocation was dropped would otherwise
pass.

Verified by reverting commit 62a7a01fde87 ("objtool/klp: Fix extraction of
text annotations for alternatives"): the output has no
.discard.annotate_insn at all and the test fails, under both gcc and clang.

Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Assisted-by: Claude:claude-opus-5
Link: https://patch.msgid.link/20260916184351.2720310-46-song@kernel.org

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