ill notice SIGKILL and abort the soon-to-begin group stop. Except: the target thread is dead (has PF_EXITING). But in that case we should not just clear SIGNAL_STOP_DEQUEUED and nothing more. We should either kill the whole thread group, or silently ignore the signal. I suspect we are not right wrt zombie leaders, but this is another issue which and should be fixed separately. Note that this check can't abort the group stop if it was already started/finished, this check only adds a subtle side effect if we race with the thread which has already dequeued sig_kernel_stop() signal and temporary released ->siglock. Signed-off-by: Oleg Nesterov Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds †8å