RFR: JDK-6546236 Thread interrupt() of Thread.sleep() can be lost on Solaris due to race with signal handler

[Daniel D. Daugherty]

 > http://cr.openjdk.java.net/~fparain/6546236/webrev.01/

src/share/vm/runtime/os.hpp
     No comments.

src/os/bsd/vm/os_bsd.inline.hpp
     If you move the Bsd::_clock_gettime check here, you should be
     able to delete Bsd::supports_monotonic_clock from
     src/os/bsd/vm/os_bsd.hpp.

src/os/bsd/vm/os_bsd.cpp
     No comments.

src/os/linux/vm/os_linux.hpp
     No comments.

src/os/linux/vm/os_linux.inline.hpp
     No comments.

src/os/linux/vm/os_linux.cpp
     No comments.

src/os/solaris/vm/os_solaris.inline.hpp
     No comments.

src/os/solaris/vm/os_solaris.cpp
     No comments.

src/os/windows/vm/os_windows.hpp
     No comments.

src/os/windows/vm/os_windows.inline.hpp
     No comments.

src/os/windows/vm/os_windows.cpp
     No comments.

src/os/posix/vm/os_posix.cpp
     line 333: assert(true, "unexpected time moving backwards detected 
in os:sleep()");
     line 375: assert(true, "unexpected time moving backwards detected 
on os::sleep()");
         These asserts will not fire. The 'true' needs to be 'false'.

     You might want to distinguish between the two different pairs of
     messages:

  332           warning("time moving backwards detected in 
os:sleep(interruptible)");
  333           assert(false, "unexpected time moving backwards detected 
in os:sleep(interruptible)");

     and:

  374           warning("time moving backwards detected on 
os::sleep(!interruptible)");
  375           assert(false, "unexpected time moving backwards detected 
on os::sleep(!interruptible)");

Dan


On 2/17/14 9:17 AM, Frederic Parain wrote:
> Hi Dan,
>
> Thank you very much for your review, I knew it was a painful review 
> with all this code moving from one directory to another. I've
> in-lined my answers below.
>
> The new webrev is here:
> http://cr.openjdk.java.net/~fparain/6546236/webrev.01/
>
> On 02/13/2014 07:14 PM, Daniel D. Daugherty wrote:
>>  > http://cr.openjdk.java.net/~fparain/6546236/webrev.00/
>>
>> Sorry for the delay. This was a difficult review to perform due to
>> the code motion between files. My technique was to use the 'udiff'
>> view for a side-by-side visual compare. Of course, this means I
>> could easily have missed critical differences... :-)
>>
>> src/os/bsd/vm/os_bsd.cpp
>>      Deletes os::sleep(), os::naked_sleep(), os::interrupt() and
>>      os::is_interrupted().
>>
>>      bsd << os::sleep >> posix
>>        << assert(!Bsd::supports_monotonic_clock(), "time moving
>> backwards");
>>        >> warning("time moving backwards");
>>            The above diff happens twice. Without at least an assert here
>>            we will be less likely to see this issue pop-up on specific
>>            test machines.
>
> I've re-written this warning. Now the warning will be printed only
> if the JVM was expecting a monotonic clock and its time warps backward.
> Note that warnings can be disabled on product builds with
> -XX:-PrintWarnings if the warning is causing trouble on VM output
> stream.
> The warning is also associated with an assert for our debug builds,
> as we discussed privately.
>
>>      bsd << os::is_interrupted >> posix
>>        picked up a long comment from the Solaris version
>>
>> src/os/linux/vm/os_linux.cpp
>>      Deletes os::sleep(), os::naked_sleep(), os::interrupt() and
>>      os::is_interrupted().
>>
>>      linux << os::sleep >> posix
>>        << assert(!Linux::supports_monotonic_clock(), "time moving
>> backwards");
>>        >> warning("time moving backwards");
>>            The above diff happens twice. Without at least an assert here
>>            we will be less likely to see this issue pop-up on specific
>>            test machines.
>
> Same comment as above.
>
>>      linux << os::is_interrupted >> posix
>>        picked up a long comment from the Solaris version
>>
>> src/os/solaris/vm/os_solaris.cpp
>>      Deletes os::sleep(), os::naked_sleep(), os::interrupt() and
>>      os::is_interrupted(). Also deletes static os_sleep() and
>>      os::Solaris::setup_interruptible_already_blocked()
>>
>>      solaris << os::interrupt >> posix
>>        << // When events are used everywhere for os::sleep, then this
>> thr_kill
>>        << // will only be needed if UseVMInterruptibleIO is true.
>>        << if (!isInterrupted) {
>>        <<   int status = thr_kill(osthread->thread_id(),
>> os::Solaris::SIGinterrupt());
>>        <<   assert_status(status == 0, status, "thr_kill");
>>            Deleting the above code presumes that you're also going to
>>            remove the remaining uses of UseVMInterruptibleIO. Should
>>            that be done with this changeset so things are not out of
>>            sync.
>
> Initially I had the fix for 6546236 and the removal of
> UseVMInterruptibleIO in the same workspace, but I split it into
> two different changesets to ease tracking in our bug database.
> The changeset to remove UseVMInterruptibleIO should be ready very
> soon after fix for 6546236 has been pushed.
>
>>        << // Bump thread interruption counter
>>        << RuntimeService::record_thread_interrupt_signaled_count();
>>            This call was only ever made on Solaris. Is this just a
>>            counter for when a SIGinterrupt has to be thrown because
>>            of the UseVMInterruptibleIO stuff?
>>
>>      Doesn't this deletion make INTERRUPTIBLE_NORESTART_VM_ALWAYS
>>      unused so it can be deleted from
>>      src/os/solaris/vm/os_solaris.inline.hpp
>>
>>      Were you also planning on removing the last vestiges of
>>      UseVMInterruptibleIO? Or will that be done with another bug?
>
> The changeset to remove UseVMInterruptibleIO includes all those cleanup:
> clean deprecation of the flag, re-work of all the macros around
> interruptible calls, cleanup of RuntimeServices methods and the
> associated performance counters.
>
>> src/os/posix/vm/os_posix.cpp
>>      Adds os::sleep(), os::naked_sleep(), os::interrupt() and
>>      os::is_interrupted().
>>
>>      > // the interrupted flag into the os::Solaris::Event structure,
>>          Should this be more generic instead of "Solaris" specific?
>
> I replaced this comment by the new version provided by David Holmes,
> so no more Solaric specific content.
>
> Thank you,
>
> Fred
>
>> On 2/10/14 8:58 AM, Frederic Parain wrote:
>>> Greetings,
>>>
>>> Please review this fix for JDK-6546236.
>>>
>>> A race condition exists in the implementation of
>>> Thread.sleep() and Thread.interrupt() on the
>>> Solaris platform. For historical reasons, the
>>> Solaris implementation of sleep() and interrupt()
>>> differs from the other Unices (Linux, BSD).
>>> It uses poll() calls while Linux and BSD are
>>> using ParkEvents.
>>>
>>> This changeset reconciles the Solaris code with
>>> Linux and BSD code. And instead of having three
>>> copies of this code, sleep() and interrupt()
>>> code are moved to the os_posix.cpp from
>>> os_[solaris|linux|bsd].cpp files.
>>>
>>> Note that with this changeset, the Solaris
>>> implementation of sleep() and interrupt()
>>> is loosing the support for UseVMInterruptibleIO
>>> but this is not an issue because this VM
>>> flag has been deprecated in JDK8 and will be
>>> removed in JDK9.
>>>
>>> The code has been tested with JPRT, vm.quick.testlist
>>> as well as jdk_lang, jdk_util, jdk_nio and jdk_awt
>>> (not a random list, all those jdk_* test suites are
>>> using Thread.sleep() and thread.interrupt()).
>>>
>>> The bug description:
>>> https://bugs.openjdk.java.net/browse/JDK-6546236
>>>
>>> The webrev:
>>> http://cr.openjdk.java.net/~fparain/6546236/webrev.00/
>>>
>>> Thank you,
>>>
>>> Fred
>>>
>>
>