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: Keep failing test workdirs by default

The klp test runner deletes each test's working directory when the test
finishes. On failure that removes diff.log, out.o and the fixture objects
befo

objtool: Keep failing test workdirs by default

The klp test runner deletes each test's working directory when the test
finishes. On failure that removes diff.log, out.o and the fixture objects
before the developer can look at them, and the only hint was to re-run
(something) with --keep:

$ make -C tools/objtool tests
...
not ok - test-special-section: expected section '.kcfi_traps' in output
...
# pass:49 fail:1 static-skip:1 probe-skip:0 xfail:0 xpass:0
# re-run with --keep to hold on to what a failing test built

Change the default behavior to save failing test working directories. This
is friendlier to the drive-by tester. Provide the power-user with a KEEP
Makefile variable that can optionally retain 'all' or 'none' of those
directories. run-tests.sh --keep remains an alias for KEEP=all.

Now that a run can be holding objects worth looking at, say where they are
when it is cut short. A Ctrl-C left the run directory behind -- the tests
clean up after themselves as they exit, but the two levels the runner made
are its own to answer for, and nothing removed them. Take them away from
a trap if the tests left them empty, and print the path if they did not:
under the new default the test that was running keeps what it had built,
and that is the run most worth being told about.

The trap only ever rmdirs, so it cannot overrule what a test decided to
keep; the same helper now serves the end of a normal run.

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
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/20260916184351.2720310-11-song@kernel.org

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objtool/klp: Run the klp tests under set -u

Most of these assertions end in a grep, and an empty pattern matches
anything. So a mistyped variable name in a test does not fail: it expands
to nothing

objtool/klp: Run the klp tests under set -u

Most of these assertions end in a grep, and an empty pattern matches
anything. So a mistyped variable name in a test does not fail: it expands
to nothing, the grep succeeds, and the test reports a pass having checked
nothing. assert_section "$sectoin_nmae" becomes a search for two adjacent
spaces, which readelf's column padding satisfies on every line.

Refuse unset variables. lib.sh guards the few genuinely optional
expansions it has with ${x:-}.

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/20260916184351.2720310-9-song@kernel.org

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objtool/klp: Give each run one working directory, one per test inside it

Each test made its own mktemp directory, so a run scattered them through
/tmp among everything else using the same names, and

objtool/klp: Give each run one working directory, one per test inside it

Each test made its own mktemp directory, so a run scattered them through
/tmp among everything else using the same names, and there was no way to
inspect what a failing test built -- the objects are gone the moment it
exits, which is right every time but the one that matters.

Give the run one directory and each test a subdirectory of it, named for
the test and nested the way the source is:

/tmp/klp-tests.3zC6oyfd/
generic/test-basic/{orig.o,patched.o,out.o,Module.symvers,...}
x86/test-kcfi/...

--keep then reports one path instead of forty, and removing it is one
command. A test run by hand still falls back to a temp directory of its
own, and still says where that went.

Detecting a leak comes free. Cleanup is now "remove each test's directory,
then rmdir the run's", and the rmdir fails if anything is left -- so a test
which dies without running its own cleanup is reported rather than quietly
leaving something behind.

preflight names the directory the tests build under, since mktemp honours
TMPDIR and a run in a container is otherwise silent about where its work
went. The runner says what to do only when it is relevant: on a failure
without --keep, that the option exists; with it, how many directories are
waiting. Usage text is not read while something is broken.

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/20260916184351.2720310-8-song@kernel.org

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objtool/klp: Grow the klp test harness vocabulary

Assertions for what klp diff produces, and for what went into it.

The output side covers the things a livepatch is made of: cloned sections
and sym

objtool/klp: Grow the klp test harness vocabulary

Assertions for what klp diff produces, and for what went into it.

The output side covers the things a livepatch is made of: cloned sections
and symbols, klp symbols and their sympos, tombstones, relocations by
section and by count, the converted .klp.rela sections and their
SHF_RELA_LIVEPATCH flag, SHN_LIVEPATCH symbols, recorded checksums, and klp
diff's own diagnostics -- a rejection for the wrong reason is not a pass.

The input side matters just as much, and is easier to forget. A test which
asserts only on the output passes when the compiler never emitted the
construct under test, and reads as coverage it does not have. So there are
two forms, and the difference between them is a statement about why the
thing might be absent:

require_* the compiler cannot produce it here -> skip
assert_* the fixture is supposed to produce it -> fail

Names are quoted before they reach grep. Nearly every name here contains
dots -- .text.target, .klp.rela.vmlinux -- and an unescaped dot matches any
character, so an assertion for one section could be satisfied by a
different one whose name merely lines up.

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/20260916184351.2720310-7-song@kernel.org

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objtool/klp: Build klp test fixtures through the harness

Compiling a fixture is the one thing every test does, and it has more
invariants than it looks.

- The flags describe the kernel a fixture

objtool/klp: Build klp test fixtures through the harness

Compiling a fixture is the one thing every test does, and it has more
invariants than it looks.

- The flags describe the kernel a fixture stands in for, and each is
written down with its reason. That substitution is the whole mechanism
by which these tests cover configurations without building a kernel --
objtool reads no .config, so a configuration reaches it only as
compiler flags and the bytes they produce -- and a flag with no stated
motive is indistinguishable from a mistake.

- -c is not one of them. Producing an object rather than a program is
the helper's contract, not something a test may reconsider, so it lives
at the compile and an override cannot drop it.

- A fixture which will not compile is a failure, not a skip. It is far
more often a mistake in the fixture than a compiler which cannot
express the construct, and the two are indistinguishable once reported
as a skip.

- A newly produced object has no checksums in it, so producing one
invalidates the record that checksumming has already been done. Left
to itself that invariant ends up in each test which rebuilds.

build_one handles a single object for the tests which need more than two or
different names; build_pair and build_module_pair are expressed in terms of
it, so none of the above can be lost by going around them.

run_checksum comes out of run_diff for the same reason: a test which wants
checksums without a diff should not have to run one.

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/20260916184351.2720310-6-song@kernel.org

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objtool/klp: Classify klp test outcomes

A test could pass, fail, or skip, and the runner reported only the exit
status of the last one to fail. Skips are the interesting case: they are
how a suite

objtool/klp: Classify klp test outcomes

A test could pass, fail, or skip, and the runner reported only the exit
status of the last one to fail. Skips are the interesting case: they are
how a suite quietly stops testing anything.

Three kinds, and the runner counts them separately:

declared the test said in advance it does not apply here, e.g. gcc_only
on a clang run. Expected indefinitely.
probe the construct did not turn up in the built object this time.
Weaker: one which becomes permanent is a fixture that stopped
testing anything.
undeclared counted as a failure. A test which gives up for a reason it
never declared is a hole, not an outcome.

xfail and xpass come with them, so a known failure is reported rather than
commented out and forgotten, and one which starts passing says so instead
of going quietly green.

The result line is what gets classified, not the whole of a test's output:
objtool warns on stderr and the runner captures it, and a stray line ahead
of the result would otherwise leave the exit status to decide -- counting
an expected failure, which exits 0, as a pass.

Every test owes the plan exactly one result line, so a substituted verdict
replaces the test's own rather than being printed beside it, and a test
which dies before reporting gets a result of its own instead of being
inferred from its exit status.

Also: a TAP version line, LC_ALL=C so the order tests run in and the
behaviour of grep's character ranges inside them do not depend on the
invoking shell's locale, and fail() on stdout with every other verdict.

Co-developed-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
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/20260916184351.2720310-5-song@kernel.org

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objtool/klp: Group the klp tests by architecture

Which architecture a test is for is expressed by where it lives: tests are
in generic/ or in a directory named for their architecture, each carrying

objtool/klp: Group the klp tests by architecture

Which architecture a test is for is expressed by where it lives: tests are
in generic/ or in a directory named for their architecture, each carrying
its own fixtures, and the runner executes generic/ plus the one that
matches. A test which cannot apply here is then not run at all, rather
than running in order to announce that it did not.

Layout does this better than a declaration would. There is no x86_only(),
and no lookup letting a fixtures/<arch>/ file shadow a generic one of the
same name -- an arch-specific test simply carries its own fixtures.

Compilers cannot work the same way: CI varies CC over the same tree, so a
compiler requirement stays a declaration in the test.

What a run leaves out is reported once:

# not run: 5 tests in x86/ (this run is arm64)

Silence would have been cheaper and wrong. A run covering less than the
tree holds must not look like a run that covered all of it.

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/20260916184351.2720310-4-song@kernel.org

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objtool/klp: Check the klp test environment once, before any test

Every test checked for itself that objtool exists, was built with klp
support, and that $CC runs. Three problems with that: it is t

objtool/klp: Check the klp test environment once, before any test

Every test checked for itself that objtool exists, was built with klp
support, and that $CC runs. Three problems with that: it is the same work
done 40 times, a missing objtool reads as a per-test skip rather than as a
suite which cannot run, and a run in which everything skipped still exits
0.

Do it once, before any test, in klp_preflight() in lib.sh, and export the
answers where the tests can read them. If the suite cannot run the whole
run fails and says why; a test which gets as far as running can assume its
environment.

Nothing is written down, so nothing can go stale. Sourcing lib.sh runs the
checks, which means a test run by hand establishes its own answers rather
than inheriting those of some earlier run with a different CC, and a test
is never handed an empty value for where objtool is or which architecture
it is on: either the exports are set or the run has already failed.

preflight answers only whether the suite can run at all -- not what the
compiler is capable of. A test needing a particular compiler feature
probes for it and skips; that costs one compile and keeps the reason next
to the test that has to justify it.

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/20260916184351.2720310-3-song@kernel.org

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objtool: Add test harness for the klp subcommands

"objtool klp checksum" and "objtool klp diff" work on object files alone,
with no kernel, vmlinux or configuration involved, so they can be tested
d

objtool: Add test harness for the klp subcommands

"objtool klp checksum" and "objtool klp diff" work on object files alone,
with no kernel, vmlinux or configuration involved, so they can be tested
directly. That is worth doing: most klp generation bugs so far have been in
symbol correlation, special section extraction and relocation conversion,
and several of them failed silently, producing a livepatch which built
cleanly but was missing data.

A test compiles a fixture twice, as the original and (with -DPATCHED) the
patched object, runs both through klp checksum, diffs them and asserts on
the result. Fixtures are compiled at test time rather than committed as
binaries: codegen varies between compilers and architectures, and that
variation is where a good number of these bugs come from.

Assertions check properties rather than compare against recorded output.
Golden files would need re-recording for every compiler change and would
report churn instead of regressions.

klp diff resolves symbols against Module.symvers, so the harness writes
one. Whether a symbol is listed there decides between an ordinary
relocation and a klp relocation, which makes it the main knob tests use.

Run with:

make -C tools/objtool tests

Tests skip when objtool was built without klp support or when a fixture
does not build for the target architecture. A missing objtool binary fails
instead of skipping, since that means a broken invocation rather than an
environment which cannot run the test.

Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Co-developed-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
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/20260916184351.2720310-2-song@kernel.org

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