4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stephane Grosjean <s.grosjean@xxxxxxxxxxxxxxx> commit e6048a00cfd0863d32f53b226e0b9a3633fc3332 upstream. This patch makes atomic the handling of the linux-can echo_skb array and the network tx queue. This prevents from the "BUG! echo_skb is occupied!" message to be printed by the linux-can core, in SMP environments. Reported-by: Diana Burgess <diana@xxxxxxxxxxxxxxxx> Signed-off-by: Stephane Grosjean <s.grosjean@xxxxxxxxxxxxxxx> Cc: linux-stable <stable@xxxxxxxxxxxxxxx> Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/can/peak_canfd/peak_canfd.c | 12 ++++++------ drivers/net/can/peak_canfd/peak_pciefd_main.c | 8 ++++++-- 2 files changed, 12 insertions(+), 8 deletions(-) --- a/drivers/net/can/peak_canfd/peak_canfd.c +++ b/drivers/net/can/peak_canfd/peak_canfd.c @@ -262,7 +262,6 @@ static int pucan_handle_can_rx(struct pe spin_lock_irqsave(&priv->echo_lock, flags); can_get_echo_skb(priv->ndev, msg->client); - spin_unlock_irqrestore(&priv->echo_lock, flags); /* count bytes of the echo instead of skb */ stats->tx_bytes += cf_len; @@ -271,6 +270,7 @@ static int pucan_handle_can_rx(struct pe /* restart tx queue (a slot is free) */ netif_wake_queue(priv->ndev); + spin_unlock_irqrestore(&priv->echo_lock, flags); return 0; } @@ -726,11 +726,6 @@ static netdev_tx_t peak_canfd_start_xmit */ should_stop_tx_queue = !!(priv->can.echo_skb[priv->echo_idx]); - spin_unlock_irqrestore(&priv->echo_lock, flags); - - /* write the skb on the interface */ - priv->write_tx_msg(priv, msg); - /* stop network tx queue if not enough room to save one more msg too */ if (priv->can.ctrlmode & CAN_CTRLMODE_FD) should_stop_tx_queue |= (room_left < @@ -742,6 +737,11 @@ static netdev_tx_t peak_canfd_start_xmit if (should_stop_tx_queue) netif_stop_queue(ndev); + spin_unlock_irqrestore(&priv->echo_lock, flags); + + /* write the skb on the interface */ + priv->write_tx_msg(priv, msg); + return NETDEV_TX_OK; } --- a/drivers/net/can/peak_canfd/peak_pciefd_main.c +++ b/drivers/net/can/peak_canfd/peak_pciefd_main.c @@ -349,8 +349,12 @@ static irqreturn_t pciefd_irq_handler(in priv->tx_pages_free++; spin_unlock_irqrestore(&priv->tx_lock, flags); - /* wake producer up */ - netif_wake_queue(priv->ucan.ndev); + /* wake producer up (only if enough room in echo_skb array) */ + spin_lock_irqsave(&priv->ucan.echo_lock, flags); + if (!priv->ucan.can.echo_skb[priv->ucan.echo_idx]) + netif_wake_queue(priv->ucan.ndev); + + spin_unlock_irqrestore(&priv->ucan.echo_lock, flags); } /* re-enable Rx DMA transfer for this CAN */