From 1ba37c518f8f83094209396c65a72732b2c1df3b Mon Sep 17 00:00:00 2001 From: Ian Campbell Date: Tue, 24 May 2011 21:56:02 +0000 Subject: [PATCH] xen: netfront: hold RTNL when updating features. Konrad reports: [ 0.930811] RTNL: assertion failed at /home/konrad/ssd/linux/net/core/dev.c (5258) [ 0.930821] Pid: 22, comm: xenwatch Not tainted 2.6.39-05193-gd762f43 #1 [ 0.930825] Call Trace: [ 0.930834] [] __netdev_update_features+0xae/0xe0 [ 0.930840] [] netdev_update_features+0x11/0x30 [ 0.930847] [] netback_changed+0x4e5/0x800 [xen_netfront] [ 0.930854] [] xenbus_otherend_changed+0xa8/0xb0 [ 0.930860] [] ? _raw_spin_unlock_irqrestore+0x19/0x20 [ 0.930866] [] backend_changed+0xe/0x10 [ 0.930871] [] xenwatch_thread+0xba/0x180 [ 0.930876] [] ? wake_up_bit+0x40/0x40 [ 0.930881] [] ? split+0xf0/0xf0 [ 0.930886] [] kthread+0x96/0xa0 [ 0.930891] [] kernel_thread_helper+0x4/0x10 [ 0.930896] [] ? int_ret_from_sys_call+0x7/0x1b [ 0.930901] [] ? retint_restore_args+0x5/0x6 [ 0.930906] [] ? gs_change+0x13/0x13 This update happens in xenbus watch callback context and hence does not already hold the rtnl. Take the lock as necessary. Signed-off-by: Ian Campbell Tested-by: Konrad Rzeszutek Wilk Signed-off-by: David S. Miller --- drivers/net/xen-netfront.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index db9a763aaa7f..d29365a232a1 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -1581,7 +1581,9 @@ static int xennet_connect(struct net_device *dev) if (err) return err; + rtnl_lock(); netdev_update_features(dev); + rtnl_unlock(); spin_lock_bh(&np->rx_lock); spin_lock_irq(&np->tx_lock); -- 2.20.1