objtool: Improve rare switch jump table pattern detection

[cascardo/linux.git] / tools / objtool / builtin-check.c

diff --git a/tools/objtool/builtin-check.c b/tools/objtool/builtin-check.c
index bd09d0e..a00a05d 100644 (file)
--- a/tools/objtool/builtin-check.c
+++ b/tools/objtool/builtin-check.c
@@ -175,6 +175,7 @@ static int __dead_end_function(struct objtool_file *file, struct symbol *func,
                "__stack_chk_fail",
                "panic",
                "do_exit",
+               "do_task_dead",
                "__module_put_and_exit",
                "complete_and_exit",
                "kvm_spurious_fault",
@@ -712,6 +713,7 @@ static struct rela *find_switch_table(struct objtool_file *file,
                                      struct instruction *insn)
 {
        struct rela *text_rela, *rodata_rela;
+       struct instruction *orig_insn = insn;
 
        text_rela = find_rela_by_dest_range(insn->sec, insn->offset, insn->len);
        if (text_rela && text_rela->sym == file->rodata->sym) {
@@ -732,10 +734,16 @@ static struct rela *find_switch_table(struct objtool_file *file,
 
        /* case 3 */
        func_for_each_insn_continue_reverse(file, func, insn) {
-               if (insn->type == INSN_JUMP_UNCONDITIONAL ||
-                   insn->type == INSN_JUMP_DYNAMIC)
+               if (insn->type == INSN_JUMP_DYNAMIC)
                        break;
 
+               /* allow small jumps within the range */
+               if (insn->type == INSN_JUMP_UNCONDITIONAL &&
+                   insn->jump_dest &&
+                   (insn->jump_dest->offset <= insn->offset ||
+                    insn->jump_dest->offset >= orig_insn->offset))
+                   break;
+
                text_rela = find_rela_by_dest_range(insn->sec, insn->offset,
                                                    insn->len);
                if (text_rela && text_rela->sym == file->rodata->sym)