- child->ptrace &= ~PT_TRACE_MASK;
-
- if (data & PTRACE_O_TRACESYSGOOD)
- child->ptrace |= PT_TRACESYSGOOD;
-
- if (data & PTRACE_O_TRACEFORK)
- child->ptrace |= PT_TRACE_FORK;
-
- if (data & PTRACE_O_TRACEVFORK)
- child->ptrace |= PT_TRACE_VFORK;
-
- if (data & PTRACE_O_TRACECLONE)
- child->ptrace |= PT_TRACE_CLONE;
-
- if (data & PTRACE_O_TRACEEXEC)
- child->ptrace |= PT_TRACE_EXEC;
-
- if (data & PTRACE_O_TRACEVFORKDONE)
- child->ptrace |= PT_TRACE_VFORK_DONE;
-
- if (data & PTRACE_O_TRACEEXIT)
- child->ptrace |= PT_TRACE_EXIT;
+ /* Avoid intermediate state when all opts are cleared */
+ flags = child->ptrace;
+ flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
+ flags |= (data << PT_OPT_FLAG_SHIFT);
+ child->ptrace = flags;