PT_PTRACED
if (ptraced & PT_PTRACED)
if (test_thread_flag(TIF_SINGLESTEP) && (current->ptrace & PT_PTRACED))
if ((current->ptrace & (PT_PTRACED|PT_SEIZED)) == PT_PTRACED)
if (!(ptrace & PT_PTRACED))
flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
flags = PT_PTRACED;
current->ptrace = PT_PTRACED;