Re: [PATCH 1/3] arch/powerpc: Add kmalloc NULL tests

On Fri, 7 Aug 2009, Daniel K. wrote:

Julia Lawall wrote:

quoted

--- a/arch/powerpc/sysdev/fsl_rio.c
+++ b/arch/powerpc/sysdev/fsl_rio.c

@@ -1057,6 +1057,10 @@ int fsl_rio_setup(struct of_device *dev)
    law_start, law_size);
 

	ops = kmalloc(sizeof(struct rio_ops), GFP_KERNEL);
+	if (!ops) {
+		rc = -ENOMEM;
+		goto err_ops;
+	}
  ops->lcread = fsl_local_config_read;
  ops->lcwrite = fsl_local_config_write;
  ops->cread = fsl_rio_config_read;

@@ -1064,6 +1068,10 @@ int fsl_rio_setup(struct of_device *dev)
  ops->dsend = fsl_rio_doorbell_send;
 

	port = kzalloc(sizeof(struct rio_mport), GFP_KERNEL);
+	if (!port) {
+		rc = -ENOMEM;
+		goto err_port;
+	}
  port->id = 0;
  port->index = 0;
 

@@ -1071,7 +1079,7 @@ int fsl_rio_setup(struct of_device *dev)
  if (!priv) {
   printk(KERN_ERR "Can't alloc memory for 'priv'\n");
   rc = -ENOMEM;
-		goto err;
+		goto err_priv;
  }
 
  INIT_LIST_HEAD(&port->dbells);

@@ -1169,13 +1177,15 @@ int fsl_rio_setup(struct of_device *dev)
 
 	return 0;

err:
-	if (priv)
-		iounmap(priv->regs_win);
-	kfree(ops);
+	iounmap(priv->regs_win);
+err_priv:
	kfree(priv);
+err_port:
	kfree(port);
+err_ops:
+	kfree(ops);
  return rc;

There seems to be a goto-off-by-one error here.

If xxxx = kxalloc() fails, you goto err_xxxx, and do a kfree(xxxx) where xxxx
is
already proven to be NULL.

Is there a reason for this that eludes me?

No, I messed up...  I will fix it.

julia