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: Add test for Clang switch jump tables

For a dense enough switch Clang emits the targets as a table in
.rodata..Lswitch.table.<function> -- named after the function but not part
of it.

objtool/klp: Add test for Clang switch jump tables

For a dense enough switch Clang emits the targets as a table in
.rodata..Lswitch.table.<function> -- named after the function but not part
of it. The patched function indexes into that table, so a clone which does
not bring it along jumps through whatever the kernel's copy holds, which
after a patch that changed the switch is the wrong set of targets. An
indirect jump to a stale address reports nothing at build or load time.

The fixture asserts its own premise twice over, since both halves depend on
what this Clang chose to do: that a table was built rather than a chain of
comparisons, and that the added case actually changed it.

objtool has no switch-specific code -- the table is carried by the general
mechanism for data a cloned function references -- so this guards that
mechanism reaching an easily-mishandled shape rather than a particular
line, and the test says so. Making the table uncorrelated, the nearest
available sabotage, does not change the outcome.

Assisted-by: Claude:claude-opus-4
Based-on-test-by: Joe Lawrence <joe.lawrence@redhat.com>
Assisted-by: Claude:claude-opus-5
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://patch.msgid.link/20260916184351.2720310-58-song@kernel.org

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