objtool: Fix infinite loop in find_jump_table() (1119d265) · Commits · 戴 / test

Kristen found a hang in objtool when building with -ffunction-sections. It was caused by evergreen_pcie_gen2_enable.cold() being laid out immediately before evergreen_pcie_gen2_enable(). Since their "pfunc" is always the same, find_jump_table() got into an infinite loop because it didn't recognize the boundary between the two functions. Fix that with a new prev_insn_same_sym() helper, which doesn't cross subfunction boundaries. Reported-by:

Kristen Carlson Accardi <kristen@linux.intel.com> Signed-off-by:

Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/378b51c9d9c894dc3294bc460b4b0869e950b7c5.1588110291.git.jpoimboe@redhat.com

tools/objtool/check.c

+13 −2

Original line number	Diff line number	Diff line
		@@ -72,6 +72,17 @@ static struct instruction next_insn_same_func(struct objtool_file file,
		return find_insn(file, func->cfunc->sec, func->cfunc->offset);
		}

		static struct instruction prev_insn_same_sym(struct objtool_file file,
		struct instruction *insn)
		{
		struct instruction *prev = list_prev_entry(insn, list);

		if (&prev->list != &file->insn_list && prev->func == insn->func)
		return prev;

		return NULL;
		}

		#define func_for_each_insn(file, func, insn) \
		for (insn = find_insn(file, func->sec, func->offset); \
		insn; \
		@@ -1050,8 +1061,8 @@ static struct rela find_jump_table(struct objtool_file file,
		* it.
		*/
		for (;
		&insn->list != &file->insn_list && insn->func && insn->func->pfunc == func;
		insn = insn->first_jump_src ?: list_prev_entry(insn, list)) {
		insn && insn->func && insn->func->pfunc == func;
		insn = insn->first_jump_src ?: prev_insn_same_sym(file, insn)) {

		if (insn != orig_insn && insn->type == INSN_JUMP_DYNAMIC)
		break;

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