netdev - Re: [PATCH] net: phy: Handle postive return codes in phy

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Date:	Sat, 5 Sep 2015 13:11:51 -0700
From:	Florian Fainelli <f.fainelli@...il.com>
To:	Andrew Lunn <andrew@...n.ch>, Michael Welling <mwelling@...e.org>
Cc:	netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] net: phy: Handle postive return codes in phy_connect

Le 09/05/15 12:47, Andrew Lunn a écrit :
> On Sat, Sep 05, 2015 at 02:44:01PM -0500, Michael Welling wrote:
>> On Sat, Sep 05, 2015 at 09:18:40PM +0200, Andrew Lunn wrote:
>>> On Sat, Sep 05, 2015 at 01:01:29PM -0500, Michael Welling wrote:
>>>> The function phy_connect_direct can possibly return a positive
>>>> return code. Using ERR_PTR with a positive value can lead to
>>>> deferencing of an invalid pointer.
>>>
>>> Is this the correct fix? Would it not be better to find where the
>>> positive return code is from and fix that?
>>
>> I guess I can trace it back to find out where the positive return code
>> is originating.
>>
>> Is phy_connect_direct always supposed to return valid -errno?
> 
> I would look at this from a different angle. A positive ERRNO is
> probably a bug of some sort. So rather than papering over the cracks,
> go find what the real issue is.

Agreed, you could place a WARN_ON(rc > 0) and get the offending call
trace leading to that problem. I suspect that one of the PHY drivers
might be returning a positive value as part of a phy_read() call and
that does not get properly filtered out.

> 
> It might not be an ERRNO. E.g. https://lkml.org/lkml/2015/9/3/534
> fixed a bug where a positive value is returned which is not an
> indication of an error.
> 
> 	   Andrew
> 
-- 
Florian
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