• Neil Horman's avatar
    bonding: Fix broken promiscuity reference counting issue · 5a0068de
    Neil Horman authored
    Recently grabbed this report:
    https://bugzilla.redhat.com/show_bug.cgi?id=1005567
    
    Of an issue in which the bonding driver, with an attached vlan encountered the
    following errors when bond0 was taken down and back up:
    
    dummy1: promiscuity touches roof, set promiscuity failed. promiscuity feature of
    device might be broken.
    
    The error occurs because, during __bond_release_one, if we release our last
    slave, we take on a random mac address and issue a NETDEV_CHANGEADDR
    notification.  With an attached vlan, the vlan may see that the vlan and bond
    mac address were in sync, but no longer are.  This triggers a call to dev_uc_add
    and dev_set_rx_mode, which enables IFF_PROMISC on the bond device.  Then, when
    we complete __bond_release_one, we use the current state of the bond flags to
    determine if we should decrement the promiscuity of the releasing slave.  But
    since the bond changed promiscuity state during the release operation, we
    incorrectly decrement the slave promisc count when it wasn't in promiscuous mode
    to begin with, causing the above error
    
    Fix is pretty simple, just cache the bonding flags at the start of the function
    and use those when determining the need to set promiscuity.
    
    This is also needed for the ALLMULTI flag
    
    CC: Jay Vosburgh <fubar@us.ibm.com>
    CC: Andy Gospodarek <andy@greyhouse.net>
    CC: Mark Wu <wudxw@linux.vnet.ibm.com>
    CC: "David S. Miller" <davem@davemloft.net>
    Reported-by: default avatarMark Wu <wudxw@linux.vnet.ibm.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    5a0068de
bond_main.c 126 KB