From 68294b023ff7d637dbd617a93aa435e1b894760f Mon Sep 17 00:00:00 2001 From: Sebastian Siewior Date: Wed, 7 Mar 2012 10:19:28 +0000 Subject: net/usbnet: avoid recursive locking in usbnet_stop() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 4231d47e6fe69f061f96c98c30eaf9fb4c14b96d upstream. |kernel BUG at kernel/rtmutex.c:724! |[] (rt_spin_lock_slowlock+0x108/0x2bc) from [] (defer_bh+0x1c/0xb4) |[] (defer_bh+0x1c/0xb4) from [] (rx_complete+0x14c/0x194) |[] (rx_complete+0x14c/0x194) from [] (usb_hcd_giveback_urb+0xa0/0xf0) |[] (usb_hcd_giveback_urb+0xa0/0xf0) from [] (musb_giveback+0x34/0x40) |[] (musb_giveback+0x34/0x40) from [] (musb_advance_schedule+0xb4/0x1c0) |[] (musb_advance_schedule+0xb4/0x1c0) from [] (musb_cleanup_urb.isra.9+0x80/0x8c) |[] (musb_cleanup_urb.isra.9+0x80/0x8c) from [] (musb_urb_dequeue+0xec/0x108) |[] (musb_urb_dequeue+0xec/0x108) from [] (unlink1+0xbc/0xcc) |[] (unlink1+0xbc/0xcc) from [] (usb_hcd_unlink_urb+0x54/0xa8) |[] (usb_hcd_unlink_urb+0x54/0xa8) from [] (unlink_urbs.isra.17+0x2c/0x58) |[] (unlink_urbs.isra.17+0x2c/0x58) from [] (usbnet_terminate_urbs+0x94/0x10c) |[] (usbnet_terminate_urbs+0x94/0x10c) from [] (usbnet_stop+0x100/0x15c) |[] (usbnet_stop+0x100/0x15c) from [] (__dev_close_many+0x94/0xc8) defer_bh() takes the lock which is hold during unlink_urbs(). The safe walk suggest that the skb will be removed from the list and this is done by defer_bh() so it seems to be okay to drop the lock here. Reported-by: Aníbal Almeida Pinto Signed-off-by: Sebastian Andrzej Siewior Acked-by: Oliver Neukum Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/usbnet.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers') diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c index ce395fe5de26..4918cf54c47d 100644 --- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -585,6 +585,7 @@ static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q) entry = (struct skb_data *) skb->cb; urb = entry->urb; + spin_unlock_irqrestore(&q->lock, flags); // during some PM-driven resume scenarios, // these (async) unlinks complete immediately retval = usb_unlink_urb (urb); @@ -592,6 +593,7 @@ static int unlink_urbs (struct usbnet *dev, struct sk_buff_head *q) netdev_dbg(dev->net, "unlink urb err, %d\n", retval); else count++; + spin_lock_irqsave(&q->lock, flags); } spin_unlock_irqrestore (&q->lock, flags); return count; -- cgit v1.2.3