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SubjectRE: [PATCH net-next 3/3] net: stmmac: Convert to phylink and remove phylib logic
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From: Jon Hunter <jonathanh@nvidia.com>

> I have been looking at this a bit closer and I can see the problem. What
> happens is that ...
>
> 1. stmmac_mac_link_up() is called and priv->eee_active is set to false
> 2. stmmac_eee_init() is called but because priv->eee_active is false,
> timer_setup() for eee_ctrl_timer is never called.
> 3. stmmac_eee_init() returns true and so then priv->eee_enabled is set
> to true.
> 4. When stmmac_tx_clean() is called because priv->eee_enabled is set to
> true, mod_timer() is called for the eee_ctrl_timer, but because
> timer_setup() was never called, we hit the BUG defined at
> kernel/time/timer.c:952, because no function is defined for the
> timer.
>
> The following fixes it for me ...
>
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -399,10 +399,13 @@ bool stmmac_eee_init(struct stmmac_priv *priv)
> mutex_lock(&priv->lock);
>
> /* Check if it needs to be deactivated */
> - if (!priv->eee_active && priv->eee_enabled) {
> - netdev_dbg(priv->dev, "disable EEE\n");
> - del_timer_sync(&priv->eee_ctrl_timer);
> - stmmac_set_eee_timer(priv, priv->hw, 0, tx_lpi_timer);
> + if (!priv->eee_active) {
> + if (priv->eee_enabled) {
> + netdev_dbg(priv->dev, "disable EEE\n");
> + del_timer_sync(&priv->eee_ctrl_timer);
> + stmmac_set_eee_timer(priv, priv->hw, 0, tx_lpi_timer);
> + }
> + mutex_unlock(&priv->lock);
> return false;
> }
>
> It also looks like you have a potention deadlock in the current code
> because in the case of if (!priv->eee_active && priv->eee_enabled)
> you don't unlock the mutex. The above fixes this as well. I can send a
> formal patch if this looks correct.

Thanks for looking into this! The fix looks correct so if you could
submit a patch it would be great!

Thanks,
Jose Miguel Abreu
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