tracing: fprobe: Fix to remove recorded module addresses from filter

Even if there is a memory allocation failure in fprobe_addr_list_add(),
there is a partial list of module addresses. So remove the recorded
addresses from filter if exists.
This also removes the redundant ret local variable.

Fixes: a3dc298 ("tracing: fprobe: Cleanup fprobe hash when module unloading")
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
Cc: [email protected]
Reviewed-by: Menglong Dong <[email protected]>

Author: mhiramat

kernel/trace/fprobe.c

@@ -428,8 +428,9 @@ static int fprobe_addr_list_add(struct fprobe_addr_list *alist, unsigned long ad
 {
 	unsigned long *addrs;
 
-	if (alist->index >= alist->size)
-		return -ENOMEM;
+	/* Previously we failed to expand the list. */
+	if (alist->index == alist->size)
+		return -ENOSPC;
 
 	alist->addrs[alist->index++] = addr;
 	if (alist->index < alist->size)
@@ -489,7 +490,7 @@ static int fprobe_module_callback(struct notifier_block *nb,
 	for (i = 0; i < FPROBE_IP_TABLE_SIZE; i++)
 		fprobe_remove_node_in_module(mod, &fprobe_ip_table[i], &alist);
 
-	if (alist.index < alist.size && alist.index > 0)
+	if (alist.index > 0)
 		ftrace_set_filter_ips(&fprobe_graph_ops.ops,
 				      alist.addrs, alist.index, 1, 0);
 	mutex_unlock(&fprobe_mutex);