From: Mathieu Desnoyers via Libc-alpha <libc-alpha@sourceware.org>
To: Florian Weimer <fweimer@redhat.com>
Cc: libc-alpha <libc-alpha@sourceware.org>,
Joseph Myers <joseph@codesourcery.com>
Subject: Re: [PATCH glibc 3/3] rseq registration tests (v10)
Date: Wed, 27 May 2020 11:30:55 -0400 (EDT) [thread overview]
Message-ID: <1836177767.36809.1590593455249.JavaMail.zimbra@efficios.com> (raw)
In-Reply-To: <87367lh09t.fsf@oldenburg2.str.redhat.com>
----- On May 27, 2020, at 11:21 AM, Florian Weimer fweimer@redhat.com wrote:
> * Mathieu Desnoyers:
>
>> ----- On May 27, 2020, at 11:12 AM, Florian Weimer fweimer@redhat.com wrote:
>>
>>> * Mathieu Desnoyers:
>>>
>>>>>>>> + retpid = TEMP_FAILURE_RETRY (waitpid (pid, &status, 0));
>>>>>>>> + if (retpid != pid)
>>>>>>>> + {
>>>>>>>> + FAIL_EXIT1 ("waitpid returned %ld, expected %ld",
>>>>>>>> + (long int) retpid, (long int) pid);
>>>>>>>> + }
>>>>>>>
>>>>>>> Hmm. Is the TEMP_FAILURE_RETRY really needed? Our xwaitpid does not
>>>>>>> have this.
>>>>>>
>>>>>> Then how does it deal with a signal interrupting the system call performing
>>>>>> the waitpid (EINTR) ? I do not see WNOHANG being used.
>>>>>
>>>>> It obscures spurious signals. In most test cases, if an unexpected
>>>>> signal is delivered, something is quite wrong indeed. This is why we
>>>>> don't generally hide EINTR errors.
>>>>
>>>> So it means you may have trouble using tools like strace and gdb on those
>>>> tests ? AFAIU those are heavy users of SIGSTOP and SIGCONT. Similarly for
>>>> profilers, those usually rely on a timer-driven signal.
>>>
>>> I have never seen any problems with strace due to this. ptrace has
>>> become a bit more transparent to the tracee since the early days, I
>>> think.
>>>
>>> I haven't seen problems under GDB, either, but then tests that fork can
>>> be rather annoying to debug anyway.
>>
>> OK so I'll use the xwaitpid wrapper and let this be someone else's problem.
>
> Yes please. Or support_isolate_in_subprocess.
Right, even better, thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
next prev parent reply other threads:[~2020-05-27 15:30 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-01 2:14 [PATCH glibc 0/3] Restartable Sequences enablement Mathieu Desnoyers via Libc-alpha
2020-05-01 2:14 ` [PATCH glibc 1/3] glibc: Perform rseq registration at C startup and thread creation (v19) Mathieu Desnoyers via Libc-alpha
2020-05-20 11:40 ` Florian Weimer via Libc-alpha
2020-05-25 14:51 ` Mathieu Desnoyers via Libc-alpha
2020-05-25 15:20 ` Florian Weimer via Libc-alpha
2020-05-25 17:36 ` Mathieu Desnoyers via Libc-alpha
2020-05-26 12:41 ` Florian Weimer via Libc-alpha
2020-05-26 14:32 ` Mathieu Desnoyers via Libc-alpha
2020-05-26 14:38 ` Florian Weimer via Libc-alpha
2020-05-26 14:53 ` Mathieu Desnoyers via Libc-alpha
2020-05-26 14:57 ` Florian Weimer via Libc-alpha
2020-05-26 15:22 ` Mathieu Desnoyers via Libc-alpha
2020-05-01 2:14 ` [PATCH glibc 2/3] glibc: sched_getcpu(): use rseq cpu_id TLS on Linux (v7) Mathieu Desnoyers via Libc-alpha
2020-05-20 10:14 ` Florian Weimer via Libc-alpha
2020-05-01 2:14 ` [PATCH glibc 3/3] rseq registration tests (v10) Mathieu Desnoyers via Libc-alpha
2020-05-20 10:52 ` Florian Weimer via Libc-alpha
2020-05-25 17:07 ` Mathieu Desnoyers via Libc-alpha
2020-05-26 12:47 ` Florian Weimer via Libc-alpha
2020-05-26 14:43 ` Mathieu Desnoyers via Libc-alpha
2020-05-27 15:05 ` Mathieu Desnoyers via Libc-alpha
2020-05-27 15:12 ` Florian Weimer via Libc-alpha
2020-05-27 15:17 ` Mathieu Desnoyers via Libc-alpha
2020-05-27 15:21 ` Florian Weimer via Libc-alpha
2020-05-27 15:30 ` Mathieu Desnoyers via Libc-alpha [this message]
2020-05-20 11:44 ` [PATCH glibc 0/3] Restartable Sequences enablement Florian Weimer via Libc-alpha
2020-05-25 13:52 ` Mathieu Desnoyers via Libc-alpha
2020-05-25 14:28 ` Florian Weimer via Libc-alpha
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