From: Thadeu Lima de Souza Cascardo cascardo@canonical.com
The .discard.text section is added in order to reserve BRK, with a temporary function just so it can give it a size. This adds a relocation to the return thunk, which objtool will add to the .return_sites section. Linking will then fail as there are references to the .discard.text section.
Do not add instructions from non-text sections to the list of return thunk calls, avoiding the reference to .discard.text.
Signed-off-by: Thadeu Lima de Souza Cascardo cascardo@canonical.com Acked-by: Josh Poimboeuf jpoimboe@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/objtool/check.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -1308,7 +1308,9 @@ static void add_return_call(struct objto insn->type = INSN_RETURN; insn->retpoline_safe = true;
- list_add_tail(&insn->call_node, &file->return_thunk_list); + /* Skip the non-text sections, specially .discard ones */ + if (insn->sec->text) + list_add_tail(&insn->call_node, &file->return_thunk_list); }
static bool same_function(struct instruction *insn1, struct instruction *insn2)