Commit 4cdee788 authored Sep 17, 2025 by Josh Poimboeuf

objtool: Fix "unexpected end of section" warning for alternatives



Due to the short circuiting logic in next_insn_to_validate(), control
flow may silently transition from .altinstr_replacement to .text without
a corresponding nested call to validate_branch().

As a result the validate_branch() 'sec' variable doesn't get
reinitialized, which can trigger a confusing "unexpected end of section"
warning which blames .altinstr_replacement rather than the offending
fallthrough function.

Fix that by not caching the section.  There's no point in doing that
anyway.

Acked-by: Petr Mladek <pmladek@suse.com>
Tested-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

parent 68245893

tools/objtool/check.c

+1 −4

Original line number	Diff line number	Diff line
		@@ -3512,15 +3512,12 @@ static int validate_branch(struct objtool_file file, struct symbol func,
		{
		struct alternative *alt;
		struct instruction next_insn, prev_insn = NULL;
		struct section *sec;
		u8 visited;
		int ret;

		if (func && func->ignore)
		return 0;

		sec = insn->sec;

		while (1) {
		next_insn = next_insn_to_validate(file, insn);

		@@ -3760,7 +3757,7 @@ static int validate_branch(struct objtool_file file, struct symbol func,

		WARN("%s%sunexpected end of section %s",
		func ? func->name : "", func ? "(): " : "",
		sec->name);
		insn->sec->name);
		return 1;
		}