• Eric Dumazet's avatar
    filter: fix sk_filter rcu handling · 46bcf14f
    Eric Dumazet authored
    Pavel Emelyanov tried to fix a race between sk_filter_(de|at)tach and
    sk_clone() in commit 47e958ea
    
    
    
    Problem is we can have several clones sharing a common sk_filter, and
    these clones might want to sk_filter_attach() their own filters at the
    same time, and can overwrite old_filter->rcu, corrupting RCU queues.
    
    We can not use filter->rcu without being sure no other thread could do
    the same thing.
    
    Switch code to a more conventional ref-counting technique : Do the
    atomic decrement immediately and queue one rcu call back when last
    reference is released.
    Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    46bcf14f