Man page 9 : do_signal_stop

do_signal_stop - handle group stop for SIGSTOP and other stop signals

bool do_signal_stop(int  signr );

signr
    signr causing group stop if initiating

If JOBCTL_STOP_PENDING is not set yet, initiate group stop with signr and participate in it. If already set, participate in the existing group stop. If participated in a group stop (and thus slept), true is returned with siglock released.

If ptraced, this function doesnAqt handle stop itself. Instead, JOBCTL_TRAP_STOP is scheduled and false is returned with siglock untouched. The caller must ensure that INTERRUPT trap handling takes places afterwards.

Must be called with current->sighand->siglock held, which is released on true return.

false if group stop is already cancelled or ptrace trap is scheduled. true if participated in group stop.