netdev - Re: [PATCH] [RFC] net: dsa: mv88e6xxx: Pre-initialize err in mv88e6xxx_port_bridge

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Message-ID: <87r3dtybm8.fsf@ketchup.mtl.sfl>
Date:	Mon, 25 Apr 2016 11:03:11 -0400
From:	Vivien Didelot <vivien.didelot@...oirfairelinux.com>
To:	Geert Uytterhoeven <geert@...ux-m68k.org>,
	"David S. Miller" <davem@...emloft.net>
Cc:	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	Geert Uytterhoeven <geert@...ux-m68k.org>
Subject: Re: [PATCH] [RFC] net: dsa: mv88e6xxx: Pre-initialize err in mv88e6xxx_port_bridge_join()

Hi Geert,

Geert Uytterhoeven <geert@...ux-m68k.org> writes:

> drivers/net/dsa/mv88e6xxx.c: In function ‘mv88e6xxx_port_bridge_join’:
> drivers/net/dsa/mv88e6xxx.c:2184: warning: ‘err’ may be used uninitialized in this function

Interesting, I don't have those warnings on 207afda1b5036009...

> If netdev_notifier_changeupper_info.upper_dev is ever NULL, the bridge
> parameter will be NULL too, and the function will return an
> uninitialized value.
>
> Pre-initialize err to zero to fix this.
>
> Fixes: 207afda1b5036009 ("net: dsa: mv88e6xxx: share the same default FDB")
> Signed-off-by: Geert Uytterhoeven <geert@...ux-m68k.org>
> ---
> Can this actually happen?

bridge cannot be NULL here. Also ps->ports[port].bridge_dev is assigned
to it before entering the for loop, so _mv88e6xxx_port_based_vlan_map
will be called at least for this port.

Thanks,

        Vivien