Re: [PATCH] net: ixp4xx_hss: fix duplicate HDLC netdev allocation

[Linus Walleij]

On Mon, Jun 22, 2026 at 6:30 AM Haoxiang Li <haoxiang_li2024@xxxxxxx> wrote:

> ixp4xx_hss_probe() allocates two HDLC netdevs. The first one is stored
> in ndev, initialized, and registered with register_hdlc_device(). The
> second one is stored in port->netdev and later used by the remove path
> for unregister_hdlc_device() and free_netdev().
>
> This means that the registered netdev is not the same object that is
> unregistered and freed on remove. It also leaks the first allocation if
> the second alloc_hdlcdev() call fails, and the first allocation is not
> checked before ndev is used.
>
> Older code allocated the HDLC netdev only once and stored the same object
> in both the local variable and port->netdev. The buggy conversion split
> this into two alloc_hdlcdev() calls. A later rename changed the local
> variable name to ndev, but the underlying mismatch remained.
>
> Fix this by allocating the HDLC netdev only once and assigning the same
> object to port->netdev.
>
> Fixes: 99ebe65eb9c0 ("net: ixp4xx_hss: move out assignment in if condition")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Haoxiang Li <haoxiang_li2024@xxxxxxx>

Reviewed-by: Linus Walleij <linusw@xxxxxxxxxx>

Yours,
Linus Walleij