netdev - Re: [PATCH] net phy: Check for aneg completion before setting state to PHY

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: <CAHPKR9Ltie2shuJqdSKbQcVSKwMt-Q8XTfAJRn6gXxVs5fHRwA@mail.gmail.com>
Date:	Fri, 25 Apr 2014 11:23:03 +0530
From:	Balakumaran Kannan <kumaran.4353@...il.com>
To:	Florian Fainelli <f.fainelli@...il.com>
Cc:	netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH] net phy: Check for aneg completion before setting state
 to PHY_RUNNING

On Fri, Apr 25, 2014 at 12:23 AM, Florian Fainelli <f.fainelli@...il.com> wrote:
> 2014-04-23 19:52 GMT-07:00 Balakumaran Kannan <kumaran.4353@...il.com>:
>> phy_state_machine should check whether auto-negotiatin is completed
>> before changing phydev->state from PHY_NOLINK to PHY_RUNNING. If
>> auto-negotiation is not completed phydev->state should be set to
>> PHY_AN.
>
> I need some time to review this. Just out of curiosity, is this fixing
> a bug you have encountered or was this found by state machine
> inspection?

Actually I encountered a problem that Linux-3.4 sends Neighbor Solicitation (NS)
before hardware completes auto-negotiation. The driver being used for
my hardware
is smsc911x.

While investigation on this, I came to know that state of phydev
follows this sequence
PHY_READY --> PHY_UP (in phy_start)
PHY_UP --> PHY_AN (in phy_start_aneg called by phy_state_machine)
PHY_AN --> PHY_NOLINK (in phy_state_machine. Link is down)
PHY_NOLINK --> PHY_RUNNING (in phy_state_machine. Link becomes ready)

So I felt that the sequence of PHY_AN --> PHY_RUNNING while link is up and
PHY_NOLINK --> PHY_RUNNING are different. In the earlier case aneg completion
is taken into account but not in later.

But this patch doesn't fix my problem. I made the smsc driver's open function to
poll on phy_aneg_done until auto-negotiation completes.

Here I have a doubt.
 * Linux network initialization and phy_state_machine runs in separate threads.
 * And driver doesn't bother about state of phydev.
Is it correct?
Doesn't driver need to confirm phydev is ready(PHY_RUNNING) before
returning to kernel?

Regards,
K.Balakumaran
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html