• Roland Dreier's avatar
    IPoIB: Fix deadlock on RTNL in ipoib_stop() · a77a57a1
    Roland Dreier authored
    Commit c8c2afe3 ("IPoIB: Use rtnl lock/unlock when changing device
    flags") added a call to rtnl_lock() in ipoib_mcast_join_task(), which
    is run from the ipoib_workqueue.  However, ipoib_stop() (which is run
    inside rtnl_lock()) flushes this workqueue, which leads to a deadlock
    if the join task is pending.
    
    Fix this by simply not flushing the workqueue from ipoib_stop().  It
    turns out that we really don't care about workqueue tasks running
    during or after ipoib_stop(), as long as we make sure to flush the
    workqueue before unregistering a netdev.
    
    This fixes <https://bugs.openfabrics.org/show_bug.cgi?id=1114>.
    Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
    a77a57a1
ipoib_multicast.c 24.7 KB