• Marcelo Ricardo Leitner's avatar
    sctp: fix missing wake ups in some situations · 442df042
    Marcelo Ricardo Leitner authored
    
    [ Upstream commit 7906b00f ]
    
    Commit fb586f25 ("sctp: delay calls to sk_data_ready() as much as
    possible") minimized the number of wake ups that are triggered in case
    the association receives a packet with multiple data chunks on it and/or
    when io_events are enabled and then commit 0970f5b3 ("sctp: signal
    sk_data_ready earlier on data chunks reception") moved the wake up to as
    soon as possible. It thus relies on the state machine running later to
    clean the flag that the event was already generated.
    
    The issue is that there are 2 call paths that calls
    sctp_ulpq_tail_event() outside of the state machine, causing the flag to
    linger and possibly omitting a needed wake up in the sequence.
    
    One of the call paths is when enabling SCTP_SENDER_DRY_EVENTS via
    setsockopt(SCTP_EVENTS), as noticed by Harald Welte. The other is when
    partial reliability triggers removal of chunks from the send queue when
    the application calls sendmsg().
    
    This commit fixes it by not setting the flag in case the socket is not
    owned by the user, as it won't be cleaned later. This works for
    user-initiated calls and also for rx path processing.
    
    Fixes: fb586f25 ("sctp: delay calls to sk_data_ready() as much as possible")
    Reported-by: default avatarHarald Welte <laforge@gnumonks.org>
    Signed-off-by: default avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    442df042
ulpqueue.c 29.2 KB