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    bonding: Fix RTNL: assertion failed at net/core/rtnetlink.c for 802.3ad mode · 5e5b0665
    dingtianhong authored
    The problem was introduced by the commit 1d3ee88a
    (bonding: add netlink attributes to slave link dev).
    The bond_set_active_slave() and bond_set_backup_slave()
    will use rtmsg_ifinfo to send slave's states, so these
    two functions should be called in RTNL.
    In 802.3ad mode, acquiring RTNL for the __enable_port and
    __disable_port cases is difficult, as those calls generally
    already hold the state machine lock, and cannot unconditionally
    call rtnl_lock because either they already hold RTNL (for calls
    via bond_3ad_unbind_slave) or due to the potential for deadlock
    with bond_3ad_adapter_speed_changed, bond_3ad_adapter_duplex_changed,
    bond_3ad_link_change, or bond_3ad_update_lacp_rate.  All four of
    those are called with RTNL held, and acquire the state machine lock
    second.  The calling contexts for __enable_port and __disable_port
    already hold the state machine lock, and may or may not need RTNL.
    According to the Jay's opinion, I don't think it is a problem that
    the slave don't send notify message synchronously when the status
    changed, normally the state machine is running every 100 ms, send
    the notify message at the end of the state machine if the slave's
    state changed should be better.
    I fix the problem through these steps:
    1). add a new function bond_set_slave_state() which could change
        the slave's state and call rtmsg_ifinfo() according to the input
        parameters called notify.
    2). Add a new slave parameter which called should_notify, if the slave's state
        changed and don't notify yet, the parameter will be set to 1, and then if
        the slave's state changed again, the param will be set to 0, it indicate that
        the slave's state has been restored, no need to notify any one.
    3). the __enable_port and __disable_port should not call rtmsg_ifinfo
        in the state machine lock, any change in the state of slave could
        set a flag in the slave, it will indicated that an rtmsg_ifinfo
        should be called at the end of the state machine.
    Cc: Jay Vosburgh <>
    Cc: Veaceslav Falico <>
    Cc: Andy Gospodarek <>
    Signed-off-by: default avatarDing Tianhong <>
    Signed-off-by: default avatarDavid S. Miller <>