• Eric Dumazet's avatar
    net: add pfmemalloc check in sk_add_backlog() · c7c49b8f
    Eric Dumazet authored
    Greg reported crashes hitting the following check in __sk_backlog_rcv()
    	BUG_ON(!sock_flag(sk, SOCK_MEMALLOC));
    The pfmemalloc bit is currently checked in sk_filter().
    This works correctly for TCP, because sk_filter() is ran in
    tcp_v[46]_rcv() before hitting the prequeue or backlog checks.
    For UDP or other protocols, this does not work, because the sk_filter()
    is ran from sock_queue_rcv_skb(), which might be called _after_ backlog
    queuing if socket is owned by user by the time packet is processed by
    softirq handler.
    Fixes: b4b9e355
     ("netvm: set PF_MEMALLOC as appropriate during SKB processing")
    Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
    Reported-by: default avatarGreg Thelen <gthelen@google.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>