objtool: is_fentry_call() crashes if call has no destination

Fix is_fentry_call() so that it works if a call has no destination
set (call_dest). This needs to be done in order to support intra-
function calls.

Signed-off-by: Alexandre Chartre <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Miroslav Benes <[email protected]>
Acked-by: Josh Poimboeuf <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]

Author: achartre

tools/objtool/check.c

@@ -1484,7 +1484,7 @@ static int decode_sections(struct objtool_file *file)
 
 static bool is_fentry_call(struct instruction *insn)
 {
-	if (insn->type == INSN_CALL &&
+	if (insn->type == INSN_CALL && insn->call_dest &&
 	    insn->call_dest->type == STT_NOTYPE &&
 	    !strcmp(insn->call_dest->name, "__fentry__"))
 		return true;