Linux-PHY Archive on lore.kernel.org

* Re: [PATCH net v4 1/2] net: phy: sfp: free mii_bus in sfp_i2c_mdiobus_destroy
From: Larysa Zaremba @ 2026-06-26 12:05 UTC (permalink / raw)
  To: Petr Wozniak
  Cc: Russell King, Andrew Lunn, Heiner Kallweit, Jakub Kicinski,
	David S . Miller, Eric Dumazet, Paolo Abeni, netdev, linux-kernel,
	linux-phy, Maxime Chevallier, Bjorn Mork, Aleksander Bajkowski,
	Marek Behun
In-Reply-To: <20260624084814.20972-2-petr.wozniak@gmail.com>

On Wed, Jun 24, 2026 at 10:48:13AM +0200, Petr Wozniak wrote:
> sfp_i2c_mdiobus_create() allocates the I2C MDIO bus with mdio_i2c_alloc(),
> a plain (non-devm) allocation, and registers it. sfp_i2c_mdiobus_destroy()
> only unregisters the bus and clears sfp->i2c_mii without calling
> mdiobus_free(). As the only reference to the bus is then cleared, the
> struct mii_bus is leaked.
> 
> This is hit whenever a copper/RollBall SFP module that instantiated an MDIO
> bus is removed: sfp_sm_main() takes the global teardown path and calls
> sfp_i2c_mdiobus_destroy(). sfp_cleanup(), on driver unbind, frees
> sfp->i2c_mii directly, which is why the leak only triggered on module
> hot-removal and not on unbind.
> 
> Free the bus in sfp_i2c_mdiobus_destroy() to match the allocation done in
> sfp_i2c_mdiobus_create().
> 
> Fixes: e85b1347ace6 ("net: sfp: create/destroy I2C mdiobus before PHY probe/after PHY release")
> Signed-off-by: Petr Wozniak <petr.wozniak@gmail.com>
> Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>

Reviewed-by: Larysa Zaremba <larysa.zaremba@intel.com>

> ---
>  drivers/net/phy/sfp.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
> index 03bfd8640db9..c4d274ab651e 100644
> --- a/drivers/net/phy/sfp.c
> +++ b/drivers/net/phy/sfp.c
> @@ -963,6 +963,7 @@ static int sfp_i2c_mdiobus_create(struct sfp *sfp)
>  static void sfp_i2c_mdiobus_destroy(struct sfp *sfp)
>  {
>  	mdiobus_unregister(sfp->i2c_mii);
> +	mdiobus_free(sfp->i2c_mii);
>  	sfp->i2c_mii = NULL;
>  }
>  
> -- 
> 2.51.0
> 
> 

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