C2 crash in PhaseIdealLoop::build_loop_late_post_work

[Christian Hagedorn]

Hi Martin

Yes that's unfortunate. I was able to reproduce it now by only running 
the benchmark dec-tree which also leads to the same assertion failure.

Best regards,
Christian

On 28.10.20 15:05, Doerr, Martin wrote:
> Hi Christian,
> 
> JDK-8251994 doesn't resolve this issue. The crash has occurred after it was fixed.
> 
> Seems like replay doesn't help, because we'd need a generated Scala class:
> java.lang.NoClassDefFoundError: org/apache/spark/sql/catalyst/expressions/GeneratedClass$SpecificUnsafeProjection
> Error while parsing line 6957: Can't find holder klass
> 
> Debugging with gdb and core file is not easy, either.
> 
> Best regards,
> Martin
> 
> 
>> -----Original Message-----
>> From: Christian Hagedorn <christian.hagedorn at oracle.com>
>> Sent: Dienstag, 27. Oktober 2020 16:31
>> To: Doerr, Martin <martin.doerr at sap.com>; 'hotspot-compiler-
>> dev at openjdk.java.net' <hotspot-compiler-dev at openjdk.java.net>
>> Subject: Re: C2 crash in PhaseIdealLoop::build_loop_late_post_work
>>
>> Hi Martin
>>
>> Thanks for the pointer! I will have a look at that.
>>
>> Best regards,
>> Christian
>>
>> On 27.10.20 16:28, Doerr, Martin wrote:
>>> Hi Christian,
>>>
>>> thanks for your reply.
>>>
>>> Interesting. Another issue related to JDK-8249749 was recently fixed:
>>> 8251994: VM crashed running TestComplexAddrExpr.java test with -
>> XX:UseAVX=X
>>> https://bugs.openjdk.java.net/browse/JDK-8251994
>>> Maybe it helps for this, too.
>>>
>>> I don’t have a fast reproducer atm.
>>>
>>> Best regards,
>>> Martin
>>>
>>>
>>>> -----Original Message-----
>>>> From: Christian Hagedorn <christian.hagedorn at oracle.com>
>>>> Sent: Dienstag, 27. Oktober 2020 13:03
>>>> To: Doerr, Martin <martin.doerr at sap.com>; 'hotspot-compiler-
>>>> dev at openjdk.java.net' <hotspot-compiler-dev at openjdk.java.net>
>>>> Subject: Re: C2 crash in PhaseIdealLoop::build_loop_late_post_work
>>>>
>>>> Hi Martin
>>>>
>>>> Yes, this is a known problem (see JDK-8251925). We also see it failing
>>>> with only this benchmark, often in log-regression. I played around with
>>>> different settings by just running log-regression, for example, which
>>>> did not seem to trigger it, though. Do you have a fast reproducer?
>>>>
>>>> It started to fail after JDK-8249749 which, however, just seem to have
>>>> revealed the problem.
>>>>
>>>> Best regards,
>>>> Christian
>>>>
>>>> On 27.10.20 12:07, Doerr, Martin wrote:
>>>>> Hi,
>>>>>
>>>>> we observe C2 crashes on all x86_64 platforms when running
>> Renaissance
>>>> Benchmark "log-regression" since 2020-08-10.
>>>>> (hg was at "8250848: [aarch64] nativeGotJump_at() missing call to
>> verify()."
>>>> when we've seen it first.)
>>>>>
>>>>>
>>>>> #  EXCEPTION_ACCESS_VIOLATION (0xc0000005) at
>>>> pc=0x00007ffd594e9322, pid=1439804, tid=1516348
>>>>>
>>>>> #
>>>>>
>>>>> # JRE version: OpenJDK Runtime Environment (16.0.0.1) (build 16.0.0.1-
>>>> internal+0-adhoc.openjdk.jdk-dev)
>>>>>
>>>>> # Java VM: OpenJDK 64-Bit Server VM (16.0.0.1-internal+0-
>>>> adhoc.openjdk.jdk-dev, mixed mode, sharing, tiered, compressed oops,
>> g1
>>>> gc, windows-amd64)
>>>>>
>>>>> # Problematic frame:
>>>>>
>>>>> # V  [jvm.dll+0x559322]
>>>> PhaseIdealLoop::build_loop_late_post_work+0x212
>>>>>
>>>>>
>>>>>
>>>>> Host: Intel(R) Xeon(R) CPU E7-8880 v4 @ 2.20GHz, 8 cores, 15G,
>> Windows
>>>> Server 2016 , 64 bit Build 14393 (10.0.14393.3630)
>>>>>
>>>>> Time: Sat Oct 24 19:40:57 2020 W. Europe Daylight Time elapsed time:
>>>> 16.016253 seconds (0d 0h 0m 16s)
>>>>>
>>>>>
>>>>> V  [jvm.dll+0x559322]
>> PhaseIdealLoop::build_loop_late_post_work+0x212
>>>> (loopnode.cpp:5312)
>>>>>
>>>>> V  [jvm.dll+0x5590b4]  PhaseIdealLoop::build_loop_late+0x214
>>>> (loopnode.cpp:5159)
>>>>>
>>>>> V  [jvm.dll+0x558418]  PhaseIdealLoop::build_and_optimize+0x7b8
>>>> (loopnode.cpp:3874)
>>>>>
>>>>> V  [jvm.dll+0x21410a]  Compile::optimize_loops+0x15a
>> (compile.cpp:1960)
>>>>>
>>>>> V  [jvm.dll+0x20d900]  Compile::Optimize+0xf90  (compile.cpp:2184)
>>>>>
>>>>> V  [jvm.dll+0x20b105]  Compile::Compile+0xba5  (compile.cpp:735)
>>>>>
>>>>> V  [jvm.dll+0x19de6b]  C2Compiler::compile_method+0xab
>>>> (c2compiler.cpp:104)
>>>>>
>>>>> Is this a known problem?
>>>>>
>>>>> Best regards,
>>>>> Martin
>>>>>