uprobes/tracing: Fix dentry/mount leak in create_trace_uprobe()

create_trace_uprobe() does kern_path() to find ->d_inode, but forgets
to do path_put(). We can do this right after igrab().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

kernel/trace/trace_uprobe.c

@@ -253,16 +253,18 @@ static int create_trace_uprobe(int argc, char **argv)
 	if (ret)
 		goto fail_address_parse;
 
-	ret = kstrtoul(arg, 0, &offset);
-	if (ret)
-		goto fail_address_parse;
-
 	inode = igrab(path.dentry->d_inode);
+	path_put(&path);
+
 	if (!S_ISREG(inode->i_mode)) {
 		ret = -EINVAL;
 		goto fail_address_parse;
 	}
 
+	ret = kstrtoul(arg, 0, &offset);
+	if (ret)
+		goto fail_address_parse;
+
 	argc -= 2;
 	argv += 2;