Re: [PATCH 2/2] can: m_can: m_can_class_allocate_dev(): remove impossible error return judgment

On 05.02.2021 16:46:16, Xulin Sun wrote:

On 2021/2/5 下午4:19, Marc Kleine-Budde wrote:

quoted

On 05.02.2021 15:25:59, Xulin Sun wrote:

quoted

If the previous can_net device has been successfully allocated, its
private data structure is impossible to be empty, remove this redundant
error return judgment. Otherwise, memory leaks for alloc_candev() will
be triggered.

Your analysis is correct, the netdev_priv() will never fail. But how
will this trigger a mem leak on alloc_candev()? I've removed that

The previous code judges the netdev_priv is empty, and then goto out. The
correct approach should add free_candev(net_dev) before goto.

The code Like:

        class_dev = netdev_priv(net_dev);
        if (!class_dev) {
                dev_err(dev, "Failed to init netdev cdevate");
+               free_candev(net_dev);
                goto out;
        }

Otherwise, memory leaks for alloc_candev() will be triggered.

No - as you said in the original patch description. The return value
of netdev_priv() cannot be NULL, as net_dev is not NULL.

Now directly remove the impossible error return judgment to resolve
the above possible issue.

Marc

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