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

[Daniel K.]

Julia Lawall wrote:

--- 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?


I'd expect that last hunk to look something like

@@ -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);
        kfree(priv);
+err_priv:
        kfree(port);
+err_port:
+       kfree(ops);
+err_ops:
        return rc;
}


Daniel K.
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev