netdev - Re: [PATCH v2 net 3/4] net: dsa: mv88e6xxx: Never force link on in-band managed MACs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <b8a26f52-c8a6-4c38-8df6-ca058c9e328d@lunn.ch>
Date: Thu, 19 Dec 2024 14:43:06 +0100
From: Andrew Lunn <andrew@...n.ch>
To: Tobias Waldekranz <tobias@...dekranz.com>
Cc: davem@...emloft.net, kuba@...nel.org, f.fainelli@...il.com,
	olteanv@...il.com, netdev@...r.kernel.org, linux@...linux.org.uk,
	chris.packham@...iedtelesis.co.nz, pabeni@...hat.com
Subject: Re: [PATCH v2 net 3/4] net: dsa: mv88e6xxx: Never force link on
 in-band managed MACs

On Thu, Dec 19, 2024 at 01:30:42PM +0100, Tobias Waldekranz wrote:
> NOTE: This issue was addressed in the referenced commit, but a
> conservative approach was chosen, where only 6095, 6097 and 6185 got
> the fix.
> 
> Before the referenced commit, in the following setup, when the PHY
> detected loss of link on the MDI, mv88e6xxx would force the MAC
> down. If the MDI-side link was then re-established later on, there was
> no longer any MII link over which the PHY could communicate that
> information back to the MAC.
> 
>         .-SGMII/USXGMII
>         |
> .-----. v .-----.   .--------------.
> | MAC +---+ PHY +---+ MDI (Cu/SFP) |
> '-----'   '-----'   '--------------'
> 
> Since this a generic problem on all MACs connected to a SERDES - which
> is the only time when in-band-status is used - move all chips to a
> common mv88e6xxx_port_sync_link() implementation which avoids forcing
> links on _all_ in-band managed ports.
> 
> Fixes: 4efe76629036 ("net: dsa: mv88e6xxx: Don't force link when using in-band-status")
> Signed-off-by: Tobias Waldekranz <tobias@...dekranz.com>

Reviewed-by: Andrew Lunn <andrew@...n.ch>

    Andrew