RFR (XS) 8202014: Possible to receive signal before signal semaphore created

[coleen.phillimore at oracle.com]

Thanks!
Coleen

On 5/18/18 9:30 AM, Thomas Stüfe wrote:
> Beautiful, thank you :)
>
> ..Thomas
>
> On Fri, May 18, 2018 at 2:59 PM,  <coleen.phillimore at oracle.com> wrote:
>>
>> On 5/18/18 8:38 AM, coleen.phillimore at oracle.com wrote:
>>>
>>>
>>> On 5/18/18 2:07 AM, Thomas Stüfe wrote:
>>>> Hi Coleen,
>>>>
>>>> looks good, thanks for taking my suggestion.
>>>>
>>>> Thoughts for further improvements:
>>>>
>>>> - os::signal_init could be renamed to something more to the point,
>>>> e.g. os::initialize_signal_dispatcher_thread() or
>>>> os::initialize_jdk_signal_support() or similar
>>>
>>> Okay os::signal_init => os::initialize_jdk_signal_support()
>>>>
>>>> - os::signal_init_pd could be removed from os.hpp altogether and made
>>>> file scope static in the os_xxx.cpp file. It could also have a better
>>>> name.
>>>
>>> os::signal_init_pd => jdk_misc_signal_init().
>>>> I leave it up to you if you do this in a follow up item, or even at
>>>> all. The fix is fine to me in its current form.
>>>
>>> I'll make these changes with this minor change.  Hopefully this is
>>> agreeable.
>>
>> http://cr.openjdk.java.net/~coleenp/8202014.03/webrev
>>
>> Rerunning oracle platform tier1,2 to make sure I didn't break anything.
>>
>> thanks,
>> Coleen
>>
>>
>>> Thanks,
>>> Coleen
>>>
>>>> Thanks, Thomas
>>>>
>>>>
>>>>
>>>>
>>>> On Thu, May 17, 2018 at 9:25 PM, <coleen.phillimore at oracle.com> wrote:
>>>>>
>>>>> On 5/16/18 2:04 AM, Thomas Stüfe wrote:
>>>>>> Hi,
>>>>>>
>>>>>> I agree with David. Signal handlers are installed in os::init_2(), but
>>>>>> the semaphore sometime later in the (imho misleadingly named) void
>>>>>> os::signal_init(). This looks like an initialization error.
>>>>>>
>>>>>> As a side note, can we make the "void signalHandler(int sig,
>>>>>> siginfo_t* info, void* uc)" functions in os_xxx.cpp static, since they
>>>>>> are only file local marshalling points?
>>>>>
>>>>> Okay, I've moved the initialization of the signal semaphore to
>>>>> os::init_2().
>>>>> The signal handler for this signal_notify() case is set up by
>>>>> JVM_RegisterSignal early in JDK initialization (initPhase1) which is
>>>>> before
>>>>> os::signal_init() was run.  Now the semaphore is initialized before
>>>>> that.
>>>>>
>>>>> I also made signalHandler static in this change although not strictly
>>>>> related.
>>>>>
>>>>> http://cr.openjdk.java.net/~coleenp/8202014.02/webrev/index.html
>>>>>
>>>>> Reran kill -INT script and mach5 hs_tiers 1 and 2.
>>>>> test/hotspot/jtreg/runtime/signal tests and
>>>>> test/jdk/sun/misc/SunMiscSignalTest.java.
>>>>>
>>>>> Thanks,
>>>>> Coleen
>>>>>
>>>>>
>>>>>> Kind Regards, Thomas
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Wed, May 16, 2018 at 4:40 AM, David Holmes <david.holmes at oracle.com>
>>>>>> wrote:
>>>>>>> Hi Coleen,
>>>>>>>
>>>>>>> On 16/05/2018 11:23 AM, coleen.phillimore at oracle.com wrote:
>>>>>>>> Summary: Don't assert for null semaphore because it can be null
>>>>>>>> before
>>>>>>>> initialization is complete.
>>>>>>>
>>>>>>> Sorry I don't agree with this. Surely we should not install our signal
>>>>>>> handler until such time as everything is properly initialized? Or the
>>>>>>> handler itself should have some kind of initialization check to guide
>>>>>>> how
>>>>>>> it
>>>>>>> responds.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> David
>>>>>>>
>>>>>>>
>>>>>>>> Tested this with a shell script, thanks Robbin, and mach5 tier1,2 all
>>>>>>>> Oracle platforms.  AIX doesn't use the semaphore class so doesn't
>>>>>>>> have
>>>>>>>> this
>>>>>>>> bug.
>>>>>>>>
>>>>>>>> open webrev at http://cr.openjdk.java.net/~coleenp/8202014.01/webrev
>>>>>>>> bug link https://bugs.openjdk.java.net/browse/JDK-8202014
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Coleen
>>>>>