linux-kernel - Re: [PATCH v2 net 1/2] net: phylink: add lock for serializing concurrent pl->phydev writes with resolver

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Message-ID: <20250903190145.n7su27upz2avqcm5@skbuf>
Date: Wed, 3 Sep 2025 22:01:45 +0300
From: Vladimir Oltean <vladimir.oltean@....com>
To: Simon Horman <horms@...nel.org>
Cc: netdev@...r.kernel.org, Andrew Lunn <andrew@...n.ch>,
	Heiner Kallweit <hkallweit1@...il.com>,
	Russell King <linux@...linux.org.uk>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 net 1/2] net: phylink: add lock for serializing
 concurrent pl->phydev writes with resolver

On Wed, Sep 03, 2025 at 07:48:58PM +0100, Simon Horman wrote:
> On Wed, Sep 03, 2025 at 06:23:47PM +0300, Vladimir Oltean wrote:
> > @@ -1582,8 +1584,11 @@ static void phylink_resolve(struct work_struct *w)
> >  	struct phylink_link_state link_state;
> >  	bool mac_config = false;
> >  	bool retrigger = false;
> > +	struct phy_device *phy;
> >  	bool cur_link_state;
> >  
> > +	mutex_lock(&pl->phy_lock);
> > +	phy = pl->phydev;
> 
> Hi Vladimir,
> 
> I guess this is an artifact of the development of this patchset.
> Whatever the case, phy is set but otherwise unused in this function.
> 
> This makes CI lightup like a Christmas tree.
> And it's a bit too early in the year for that.

Thanks for letting me know. It's an artifact of moving patch 1 in front
of 2, and I'll address this for the next revision.

I downgraded to a slower computer for kernel compilation, and even
though I did compile patch by patch this submission, I had to stop
building with W=1 C=1 for some unrelated bisect and I forgot to turn
them back on.

I don't have a great solution to this, except I'll try next time to set
up a separate 'git worktree' for noisy stuff like bisection, and try to
keep the net-next environment separate and always with build warnings
and debug options enabled.