objtool/klp: Fix .kcfi_traps special section extraction

create_fake_symbols() creates a symbol per entry for special sections.
It does so in two steps: first for the sections which have
ANNOTATE_DATA_SPECIAL annotations, then for the rest, using entsize or
the reloc count to infer the entry size.  The second step skips the
sections already handled by the first one by looking for a symbol at
offset 0.

That heuristic is too fuzzy: with Clang and CONFIG_CFI, it misfires on
.kcfi_traps because Clang emits a .Ltmp* assembler-local label at the
start of the section, so no symbols are created and
clone_special_sections() extracts nothing.  klp-build still reports
SUCCESS, but the livepatch module has no __kcfi_traps section and the
traps for the patched functions are lost.

Look for the actual fake symbols created by the first step instead.

Fixes: da4326573ae8d ("objtool/klp: Fix kCFI trap handling")
Reported-by: Joe Lawrence <joe.lawrence@redhat.com>
Closes: https://lore.kernel.org/r/akQNqlfFC0T5pcMa@redhat.com
Acked-by: Song Liu <song@kernel.org>
Link: https://patch.msgid.link/8faaead205b219607b6fc2359ae743be824056eb.1786230311.git.jpoimboe@kernel.org
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

0 files changed, 0 insertions, 0 deletions