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    Subject[PATCH 01/20] signal: Fix SIGCONT notification code
    After a task receives SIGCONT, its parent is notified via SIGCHLD with
    its siginfo describing what the notified event is. If SIGCONT is
    received while the child process is stopped, the code should be
    CLD_CONTINUED. If SIGCONT is recieved while the child process is in
    the process of being stopped, it should be CLD_STOPPED. Which code to
    use is determined in prepare_signal() and recorded in signal->flags

    get_signal_deliver() should test these flags and then notify
    accoringly; however, it incorrectly tested SIGNAL_STOP_CONTINUED
    instead of SIGNAL_CLD_CONTINUED, thus incorrectly notifying
    CLD_CONTINUED if the signal is delivered before the task is wait(2)ed
    and CLD_STOPPED if the state was fetched already.

    Fix it by testing SIGNAL_CLD_CONTINUED. While at it, uncompress the
    ?: test into if/else clause for better readability.

    Signed-off-by: Tejun Heo <>
    Reviewed-by: Oleg Nesterov <>
    Acked-by: Roland McGrath <>
    kernel/signal.c | 9 +++++++--
    1 files changed, 7 insertions(+), 2 deletions(-)

    diff --git a/kernel/signal.c b/kernel/signal.c
    index 3175186..e26274a 100644
    --- a/kernel/signal.c
    +++ b/kernel/signal.c
    @@ -1853,8 +1853,13 @@ relock:
    * the CLD_ si_code into SIGNAL_CLD_MASK bits.
    if (unlikely(signal->flags & SIGNAL_CLD_MASK)) {
    - int why = (signal->flags & SIGNAL_STOP_CONTINUED)
    + int why;
    + if (signal->flags & SIGNAL_CLD_CONTINUED)
    + why = CLD_CONTINUED;
    + else
    + why = CLD_STOPPED;
    signal->flags &= ~SIGNAL_CLD_MASK;

    why = tracehook_notify_jctl(why, CLD_CONTINUED);

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