Re: [Xenomai-core] [PATCH] Suppress switch warnings while debugging

[Jan Kiszka <jan.kiszka@domain.hid>]

Philippe Gerum wrote:
> Jan Kiszka wrote:
>> Philippe Gerum wrote:
>>> Jan Kiszka wrote:
>>>> Don't raise SIGXCPU while the process is being debugged. These mode
>>>> changes are expected, and reporting them doesn't provide any helpful
>>>> information to the application. Rather, it may raise error storms on
>>>> the
>>>> application side.
>>>>
>>>> Signed-off-by: Jan Kiszka <jan.kiszka@domain.hid>
>>>> ---
>>>>
>>>>  ksrc/nucleus/shadow.c |    3 ++-
>>>>  1 files changed, 2 insertions(+), 1 deletions(-)
>>>>
>>>> diff --git a/ksrc/nucleus/shadow.c b/ksrc/nucleus/shadow.c
>>>> index bcf3b8b..91cf499 100644
>>>> --- a/ksrc/nucleus/shadow.c
>>>> +++ b/ksrc/nucleus/shadow.c
>>>> @@ -1082,7 +1082,8 @@ void xnshadow_relax(int notify)
>>>>  
>>>>      xnstat_counter_inc(&thread->stat.ssw);    /* Account for
>>>> secondary mode switch. */
>>>>  
>>>> -    if (notify && xnthread_test_state(thread, XNTRAPSW))
>>>> +    if (notify && xnthread_test_state(thread, XNTRAPSW) &&
>>>> +        !xnthread_test_state(thread, XNDEBUG))
>>>>          /* Help debugging spurious relaxes. */
>>>>          send_sig(SIGXCPU, current, 1);
>>>>
>>> I would rather identify the source of the switch and clear the notify
>>> flag appropriately from the relax call site.
>>
>> Sorry, don't get this: What flag do you want to clear? XNTRAPSW?
>>
> 
> The "notify" parameter should set by the call site to tell
> xnshadow_relax() whether we want the SIGXCPU signal to be sent or not. I
> would rather identify which call site introduces the issue, and fix the
> notify parameter accordingly. Did you track the issue down to
> request_syscall_restart() for instance? In which case, we should rather
> test XNDEBUG there, and set the notify flag passed to xnshadow_relax()
> appropriately.

OK, now I understand. I didn't track this down yet, but it must be
request_syscall_restart, because that should be the only site that
relaxes due to pending signals. Will update the patch.

Jan

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