On 06/19/2013 06:32 PM, Oleg Nesterov wrote: > On 06/19, Denys Vlasenko wrote: >> >> This is a user-visible behavior change. >> Do we really have to introduce a separate >> PTRACE_NOT_STUPID_DETACH? I hope not. > > Oh, I think yes. > >> @@ -1062,7 +1060,8 @@ SYSCALL_DEFINE4(ptrace, long, request, long, pid, >> unsigned long, addr, >> } >> >> ret = ptrace_check_attach(child, request == PTRACE_KILL || >> - request == PTRACE_INTERRUPT); >> + request == PTRACE_INTERRUPT || >> + request == PTRACE_DETACH); > > There doesn't look right. > > For example ptrace_disable(). See the comment set_task_blockstep().
I see the comment. I think it implies that TF-induced debug interrupt may happen on the running task after it is detached, which will result in SIGTRAP being sent to it. Correct me if I'm wrong. If so, do we have the same problem if tracer exits and implicit detach is performed? -- vda -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
