From 3fe439760955370b9f005ef2728b5fc9b14eeea5 Mon Sep 17 00:00:00 2001 From: Sean Anderson Date: Thu, 28 Aug 2025 11:55:01 -0400 Subject: [PATCH net v2] net: macb: Fix tx_ptr_lock locking macb_start_xmit can be called with bottom-halves disabled (e.g. transmitting from softirqs) as well as with interrupts disabled (with netpoll). Because of this, all other functions taking tx_ptr_lock must disable IRQs, and macb_start_xmit must only re-enable IRQs if they were already enabled. Fixes: 138badbc21a0 ("net: macb: use NAPI for TX completion path") Reported-by: Mike Galbraith Signed-off-by: Sean Anderson --- Changes in v2: - Use irqsave/restore for all accesses, since they can also also be called from netpoll. drivers/net/ethernet/cadence/macb_main.c | 28 ++++++++++++++---------- 1 file changed, 16 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index 16d28a8b3b56..c769b7dbd3ba 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -1223,12 +1223,13 @@ static int macb_tx_complete(struct macb_queue *queue, int budget) { struct macb *bp = queue->bp; u16 queue_index = queue - bp->queues; + unsigned long flags; unsigned int tail; unsigned int head; int packets = 0; u32 bytes = 0; - spin_lock(&queue->tx_ptr_lock); + spin_lock_irqsave(&queue->tx_ptr_lock, flags); head = queue->tx_head; for (tail = queue->tx_tail; tail != head && packets < budget; tail++) { struct macb_tx_skb *tx_skb; @@ -1291,7 +1292,7 @@ static int macb_tx_complete(struct macb_queue *queue, int budget) CIRC_CNT(queue->tx_head, queue->tx_tail, bp->tx_ring_size) <= MACB_TX_WAKEUP_THRESH(bp)) netif_wake_subqueue(bp->dev, queue_index); - spin_unlock(&queue->tx_ptr_lock); + spin_unlock_irqrestore(&queue->tx_ptr_lock, flags); return packets; } @@ -1707,8 +1708,9 @@ static void macb_tx_restart(struct macb_queue *queue) { struct macb *bp = queue->bp; unsigned int head_idx, tbqp; + unsigned long flags; - spin_lock(&queue->tx_ptr_lock); + spin_lock_irqsave(&queue->tx_ptr_lock, flags); if (queue->tx_head == queue->tx_tail) goto out_tx_ptr_unlock; @@ -1720,19 +1722,20 @@ static void macb_tx_restart(struct macb_queue *queue) if (tbqp == head_idx) goto out_tx_ptr_unlock; - spin_lock_irq(&bp->lock); + spin_lock(&bp->lock); macb_writel(bp, NCR, macb_readl(bp, NCR) | MACB_BIT(TSTART)); - spin_unlock_irq(&bp->lock); + spin_unlock(&bp->lock); out_tx_ptr_unlock: - spin_unlock(&queue->tx_ptr_lock); + spin_unlock_irqrestore(&queue->tx_ptr_lock, flags); } static bool macb_tx_complete_pending(struct macb_queue *queue) { bool retval = false; + unsigned long flags; - spin_lock(&queue->tx_ptr_lock); + spin_lock_irqsave(&queue->tx_ptr_lock, flags); if (queue->tx_head != queue->tx_tail) { /* Make hw descriptor updates visible to CPU */ rmb(); @@ -1740,7 +1743,7 @@ static bool macb_tx_complete_pending(struct macb_queue *queue) if (macb_tx_desc(queue, queue->tx_tail)->ctrl & MACB_BIT(TX_USED)) retval = true; } - spin_unlock(&queue->tx_ptr_lock); + spin_unlock_irqrestore(&queue->tx_ptr_lock, flags); return retval; } @@ -2308,6 +2311,7 @@ static netdev_tx_t macb_start_xmit(struct sk_buff *skb, struct net_device *dev) struct macb_queue *queue = &bp->queues[queue_index]; unsigned int desc_cnt, nr_frags, frag_size, f; unsigned int hdrlen; + unsigned long flags; bool is_lso; netdev_tx_t ret = NETDEV_TX_OK; @@ -2368,7 +2372,7 @@ static netdev_tx_t macb_start_xmit(struct sk_buff *skb, struct net_device *dev) desc_cnt += DIV_ROUND_UP(frag_size, bp->max_tx_length); } - spin_lock_bh(&queue->tx_ptr_lock); + spin_lock_irqsave(&queue->tx_ptr_lock, flags); /* This is a hard error, log it. */ if (CIRC_SPACE(queue->tx_head, queue->tx_tail, @@ -2392,15 +2396,15 @@ static netdev_tx_t macb_start_xmit(struct sk_buff *skb, struct net_device *dev) netdev_tx_sent_queue(netdev_get_tx_queue(bp->dev, queue_index), skb->len); - spin_lock_irq(&bp->lock); + spin_lock(&bp->lock); macb_writel(bp, NCR, macb_readl(bp, NCR) | MACB_BIT(TSTART)); - spin_unlock_irq(&bp->lock); + spin_unlock(&bp->lock); if (CIRC_SPACE(queue->tx_head, queue->tx_tail, bp->tx_ring_size) < 1) netif_stop_subqueue(dev, queue_index); unlock: - spin_unlock_bh(&queue->tx_ptr_lock); + spin_unlock_irqrestore(&queue->tx_ptr_lock, flags); return ret; } -- 2.35.1.1320.gc452695387.dirty