From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-188.mta1.migadu.com (out-188.mta1.migadu.com [95.215.58.188]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4CED221CA02 for ; Thu, 28 Aug 2025 16:02:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.188 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756396928; cv=none; b=JNPuy8IkfZOPgvlXY9VkF8Yzzh6+JLjJGd54nhUpK3Ic9nC6KbyiBzA3o3FKukWWsfTYLgRfUUB1eHJzLo4+4pKSiiG09YTzej1WOtH7QeltqNIsoZnfjsPI6plcb8knfiZz622uZ5vgVkcnG1xSZVoBFtsj2DCq9lqLrbl0xMk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756396928; c=relaxed/simple; bh=kiX7CyAFz4TZ0E4S53d0DGM11ONPCxFAmM2tnxhh46w=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=XO5tP7aXDoWZYPX/doNfzcHrwIoyNnlcqhp6Qh52/PFTzIykpZnuhzoPuiDH4HqeIcAGA2HK87QWa1z7I+czUR9UcKPmqCVG3EnxcvioR3rOm668OGSnvphAnJ8u29OekALuBjMRjz5wdAejFOGroCOScCtqhLfUaSyK/58mneE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=i81Gyigj; arc=none smtp.client-ip=95.215.58.188 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="i81Gyigj" Message-ID: <794443b3-2f6d-4400-8844-6c8cdffd3be2@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1756396913; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=F34gXWs5azrE0OhbBDQ6CECJveSxbrw+7RsGT9yHBpo=; b=i81GyigjAdLCBhKAmtdN2MrGo3LqWPbqY4aTMllZThQ0+tzjtBcqvH20bb6Tc4pzuUqc05 W99JfExr51YpCNY8x848lNrzDm7CFf3h6VPE5mNE/a4o5i4BJ2k/hseEtEQsoJbJJLIhX5 5TUYqnE1zAxqgRYqMenFu+jmpA049DE= Date: Thu, 28 Aug 2025 12:01:34 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH] net: macb: Fix tx_ptr_lock locking To: Andrew Lunn , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org Cc: Robert Hancock , Mike Galbraith , Claudiu Beznea , linux-kernel@vger.kernel.org, Nicolas Ferre References: <20250828160023.1505762-1-sean.anderson@linux.dev> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Sean Anderson In-Reply-To: <20250828160023.1505762-1-sean.anderson@linux.dev> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 8/28/25 12:00, Sean Anderson wrote: > 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 > --- > > drivers/net/ethernet/cadence/macb_main.c | 25 ++++++++++++------------ > 1 file changed, 13 insertions(+), 12 deletions(-) > > diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c > index 16d28a8b3b56..b0a8dfa341ea 100644 > --- a/drivers/net/ethernet/cadence/macb_main.c > +++ b/drivers/net/ethernet/cadence/macb_main.c > @@ -1228,7 +1228,7 @@ static int macb_tx_complete(struct macb_queue *queue, int budget) > int packets = 0; > u32 bytes = 0; > > - spin_lock(&queue->tx_ptr_lock); > + spin_lock_irq(&queue->tx_ptr_lock); > head = queue->tx_head; > for (tail = queue->tx_tail; tail != head && packets < budget; tail++) { > struct macb_tx_skb *tx_skb; > @@ -1291,7 +1291,7 @@ 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_irq(&queue->tx_ptr_lock); > > return packets; > } > @@ -1708,7 +1708,7 @@ static void macb_tx_restart(struct macb_queue *queue) > struct macb *bp = queue->bp; > unsigned int head_idx, tbqp; > > - spin_lock(&queue->tx_ptr_lock); > + spin_lock_irq(&queue->tx_ptr_lock); > > if (queue->tx_head == queue->tx_tail) > goto out_tx_ptr_unlock; > @@ -1720,19 +1720,19 @@ 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_irq(&queue->tx_ptr_lock); > } > > static bool macb_tx_complete_pending(struct macb_queue *queue) > { > bool retval = false; > > - spin_lock(&queue->tx_ptr_lock); > + spin_lock_irq(&queue->tx_ptr_lock); > if (queue->tx_head != queue->tx_tail) { > /* Make hw descriptor updates visible to CPU */ > rmb(); > @@ -1740,7 +1740,7 @@ 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_irq(&queue->tx_ptr_lock); > return retval; > } > > @@ -2308,6 +2308,7 @@ 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 +2369,7 @@ 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 +2393,15 @@ 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; > } Sorry, this should be [PATCH net]. --Sean