Hi! > The driver uses a private lock for synchronization between the xmit > function and the xmit completion handler, but since the NETIF_F_LLTX flag > is not set, the xmit function is also called with the xmit_lock held. > > On the other hand the xmit completion handler first takes the private lock > and (in case that the tx queue has been stopped) the xmit_lock, leading to > a reverse locking order and the potential danger of a deadlock. > > Fix this by removing the private lock completely and synchronizing the xmit > function and completion handler solely by means of the xmit_lock. By doing > this remove also the now unnecessary double check for a stopped tx queue. > > Signed-off-by: Lino Sanfilippo <linosanfili...@gmx.de>
Does not seem to apply to net-next based on
adc176c5472214971d77c1a61c83db9b01e9cdc7. Aha, that's the printk()
changes, probably would apply to mainline.
> index caf069a..db46ec4 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -1307,7 +1307,7 @@ static void stmmac_tx_clean(struct stmmac_priv *priv)
> unsigned int bytes_compl = 0, pkts_compl = 0;
> unsigned int entry = priv->dirty_tx;
>
> - spin_lock(&priv->tx_lock);
> + netif_tx_lock(priv->dev);
>
> priv->xstats.tx_clean++;
>
Should it use "netif_tx_lock_bh"?
I could not reproduce the deadlock without this patch, nor can I
detect anything wrong with this patch, so I guess that is:
Tested-by: Pavel Machek <pa...@denx.de>
Thanks,
Pavel
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