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SubjectRe: [PATCH] net: dsa: avoid null pointer dereference on p->phy
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On 09/23/2017 09:57 AM, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> Currently p->phy is being null checked in several places to avoid
> null pointer dereferences on p->phy, however, the final call
> to phy_attached_info on p->phy when p->phy will perform a null
> pointer dereference. Fix this by simply moving the call into
> the previous code block that is only executed if p->phy is
> not null.
>
> Detected by CoverityScan, CID#1457034 ("Dereference after null check")

The code flow is not exactly easy to read, but I don't see how we can
actually wind up in that situation because we check the return values of
of_phy_connect() and dsa_slave_phy_connect() earlier on.

>
> Fixes: 2220943a21e2 ("phy: Centralise print about attached phy")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> net/dsa/slave.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/net/dsa/slave.c b/net/dsa/slave.c
> index 02ace7d462c4..29ab4e98639b 100644
> --- a/net/dsa/slave.c
> +++ b/net/dsa/slave.c
> @@ -1115,10 +1115,9 @@ static int dsa_slave_phy_setup(struct net_device *slave_dev)
> of_phy_deregister_fixed_link(port_dn);
> return ret;
> }
> + phy_attached_info(p->phy);
> }
>
> - phy_attached_info(p->phy);
> -
> return 0;
> }
>
>

--
Florian

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