From 789851cf0005b946557340c9bbfc7728906cdbfc Mon Sep 17 00:00:00 2001 From: David Brownell Date: Mon, 21 Aug 2006 15:26:38 -0700 Subject: [PATCH] usb gadget: g_ether spinlock recursion fix The new spinlock debug code turned up a spinlock recursion bug in the Ethernet gadget driver on a disconnect path; it would show up with any UDC driver where the cancellation of active requests was synchronous, rather than e.g. delayed until a controller's completion IRQ. That recursion is fixed here by creating and using a new spinlock to protect the relevant lists. Signed-off-by: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/ether.c | 45 ++++++++++++++++++++++++++------------ 1 file changed, 31 insertions(+), 14 deletions(-) diff --git a/drivers/usb/gadget/ether.c b/drivers/usb/gadget/ether.c index 4fe1bec1c25..30299c620d9 100644 --- a/drivers/usb/gadget/ether.c +++ b/drivers/usb/gadget/ether.c @@ -117,6 +117,8 @@ struct eth_dev { struct usb_ep *in_ep, *out_ep, *status_ep; const struct usb_endpoint_descriptor *in, *out, *status; + + spinlock_t req_lock; struct list_head tx_reqs, rx_reqs; struct net_device *net; @@ -1066,21 +1068,31 @@ static void eth_reset_config (struct eth_dev *dev) */ if (dev->in) { usb_ep_disable (dev->in_ep); + spin_lock(&dev->req_lock); while (likely (!list_empty (&dev->tx_reqs))) { req = container_of (dev->tx_reqs.next, struct usb_request, list); list_del (&req->list); + + spin_unlock(&dev->req_lock); usb_ep_free_request (dev->in_ep, req); + spin_lock(&dev->req_lock); } + spin_unlock(&dev->req_lock); } if (dev->out) { usb_ep_disable (dev->out_ep); + spin_lock(&dev->req_lock); while (likely (!list_empty (&dev->rx_reqs))) { req = container_of (dev->rx_reqs.next, struct usb_request, list); list_del (&req->list); + + spin_unlock(&dev->req_lock); usb_ep_free_request (dev->out_ep, req); + spin_lock(&dev->req_lock); } + spin_unlock(&dev->req_lock); } if (dev->status) { @@ -1659,9 +1671,9 @@ enomem: if (retval) { DEBUG (dev, "rx submit --> %d\n", retval); dev_kfree_skb_any (skb); - spin_lock (&dev->lock); + spin_lock(&dev->req_lock); list_add (&req->list, &dev->rx_reqs); - spin_unlock (&dev->lock); + spin_unlock(&dev->req_lock); } return retval; } @@ -1730,8 +1742,9 @@ quiesce: dev_kfree_skb_any (skb); if (!netif_running (dev->net)) { clean: - /* nobody reading rx_reqs, so no dev->lock */ + spin_lock(&dev->req_lock); list_add (&req->list, &dev->rx_reqs); + spin_unlock(&dev->req_lock); req = NULL; } if (req) @@ -1782,15 +1795,18 @@ static int alloc_requests (struct eth_dev *dev, unsigned n, gfp_t gfp_flags) { int status; + spin_lock(&dev->req_lock); status = prealloc (&dev->tx_reqs, dev->in_ep, n, gfp_flags); if (status < 0) goto fail; status = prealloc (&dev->rx_reqs, dev->out_ep, n, gfp_flags); if (status < 0) goto fail; - return 0; + goto done; fail: DEBUG (dev, "can't alloc requests\n"); +done: + spin_unlock(&dev->req_lock); return status; } @@ -1800,21 +1816,21 @@ static void rx_fill (struct eth_dev *dev, gfp_t gfp_flags) unsigned long flags; /* fill unused rxq slots with some skb */ - spin_lock_irqsave (&dev->lock, flags); + spin_lock_irqsave(&dev->req_lock, flags); while (!list_empty (&dev->rx_reqs)) { req = container_of (dev->rx_reqs.next, struct usb_request, list); list_del_init (&req->list); - spin_unlock_irqrestore (&dev->lock, flags); + spin_unlock_irqrestore(&dev->req_lock, flags); if (rx_submit (dev, req, gfp_flags) < 0) { defer_kevent (dev, WORK_RX_MEMORY); return; } - spin_lock_irqsave (&dev->lock, flags); + spin_lock_irqsave(&dev->req_lock, flags); } - spin_unlock_irqrestore (&dev->lock, flags); + spin_unlock_irqrestore(&dev->req_lock, flags); } static void eth_work (void *_dev) @@ -1848,9 +1864,9 @@ static void tx_complete (struct usb_ep *ep, struct usb_request *req) } dev->stats.tx_packets++; - spin_lock (&dev->lock); + spin_lock(&dev->req_lock); list_add (&req->list, &dev->tx_reqs); - spin_unlock (&dev->lock); + spin_unlock(&dev->req_lock); dev_kfree_skb_any (skb); atomic_dec (&dev->tx_qlen); @@ -1896,12 +1912,12 @@ static int eth_start_xmit (struct sk_buff *skb, struct net_device *net) /* ignores USB_CDC_PACKET_TYPE_DIRECTED */ } - spin_lock_irqsave (&dev->lock, flags); + spin_lock_irqsave(&dev->req_lock, flags); req = container_of (dev->tx_reqs.next, struct usb_request, list); list_del (&req->list); if (list_empty (&dev->tx_reqs)) netif_stop_queue (net); - spin_unlock_irqrestore (&dev->lock, flags); + spin_unlock_irqrestore(&dev->req_lock, flags); /* no buffer copies needed, unless the network stack did it * or the hardware can't use skb buffers. @@ -1955,11 +1971,11 @@ static int eth_start_xmit (struct sk_buff *skb, struct net_device *net) drop: dev->stats.tx_dropped++; dev_kfree_skb_any (skb); - spin_lock_irqsave (&dev->lock, flags); + spin_lock_irqsave(&dev->req_lock, flags); if (list_empty (&dev->tx_reqs)) netif_start_queue (net); list_add (&req->list, &dev->tx_reqs); - spin_unlock_irqrestore (&dev->lock, flags); + spin_unlock_irqrestore(&dev->req_lock, flags); } return 0; } @@ -2378,6 +2394,7 @@ autoconf_fail: return status; dev = netdev_priv(net); spin_lock_init (&dev->lock); + spin_lock_init (&dev->req_lock); INIT_WORK (&dev->work, eth_work, dev); INIT_LIST_HEAD (&dev->tx_reqs); INIT_LIST_HEAD (&dev->rx_reqs); -- 2.41.0