linux-toradex.git/tools/objtool/tests/x86/fixtures/empty_alternative.c, branch master Linux kernel for Apalis and Colibri modules objtool/klp: Add test for empty x86 alternative replacements 2026-09-21T09:12:06+00:00 Song Liu song@kernel.org 2026-09-16T18:43:27+00:00 dff07c58cae7f60e7ae08e9c005e8ec125391f98 ALTERNATIVE_2("orig", "repl", ft1, "", ft2) produces a second entry whose replacement is empty. Its replacement offset still carries a relocation, but the label it points at is the end of the previous replacement -- which is also where the next one begins. The value is meaningless and only ever used with a length of zero, so cloning must not follow it. The first version of this fixture passed with the fix reverted, because the empty entry pointed at its own end label rather than at the neighbour's replacement. It has to reach into another function's replacement to distinguish the behaviour. This tests the behavior of commit 636f230ce21e ("objtool/klp: Ignore replacement offset of empty x86 alternatives"). 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/20260916184351.2720310-35-song@kernel.org 
ALTERNATIVE_2("orig", "repl", ft1, "", ft2) produces a second entry whose
replacement is empty.  Its replacement offset still carries a relocation,
but the label it points at is the end of the previous replacement -- which
is also where the next one begins.  The value is meaningless and only ever
used with a length of zero, so cloning must not follow it.

The first version of this fixture passed with the fix reverted, because the
empty entry pointed at its own end label rather than at the neighbour's
replacement.  It has to reach into another function's replacement to
distinguish the behaviour.

This tests the behavior of commit 636f230ce21e ("objtool/klp: Ignore
replacement offset of empty x86 alternatives").

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/20260916184351.2720310-35-song@kernel.org