Segfault when running compiled Truffle method.

[Wei Zhang]

Thanks to Bernhard and Andreas for the fix.

I probably should be more careful with frame creation....

Cheers,
/Wei


On Thu, Jan 23, 2014 at 6:52 AM, Andreas Woess <andreas.woess at jku.at> wrote:
> Thanks to Bernhard for debugging the crash.
> The problem is how you create the materialized frame for the generator.
> In the PGenerator constructor you have:
>>  MaterializedFrame generatorFrame = new
>> DefaultVirtualFrame(frameDescriptor, null,
>> PArguments.EMPTY_ARGUMENT).materialize();
>
> Please replace this with:
> Truffle.getRuntime().createMaterializedFrame(...) -- Bernhard has sent
> you a pull request.
> Otherwise the unsafeFrameCast which you have in PArguments is not
> correct. The reason it worked in the other case is probably that you
> don't have the unsafeFrameCast in GeneratorArguments.getGeneratorFrame().
>
> In general, never create frames yourself, always use the methods in
> TruffleRuntime (there's also one for virtual frames nowadays, should you
> need it).
>
> - andreas
>
> On 23.01.2014 07:06, Wei Zhang wrote:
>> Hi,
>>
>> I was able to extract a smaller Python program that reproduces crash
>> that I reported earlier.
>>
>> ---------------------------------------------------------
>> def generator(n):
>>     alist = [j for j in range(n)]
>>     for i in range(n):
>>         yield list(alist[x] for x in range(i))
>>
>> for i in generator(10000):
>>     result = i
>>
>> print(i[-1])
>> ---------------------------------------------------------
>>
>> The following command runs the test program shown above and reproduces
>> the crash (with the latest commit from ZipPy):
>> ./mx.sh python graal/edu.uci.python.test/src/tests/generator-yield-call-with-genexp-test.py
>> -OptimizeGeneratorExpressions:false
>>
>> I can confirm that the generator expression in the yield statement of
>> the 'generator' function causes the problem.
>> Because if I do not disable -OptimizeGeneratorExpressions options, the
>> generator expression semantic is optimized away and it works fine.
>>
>> As soon as that generator expression is compiled, the crash happens.
>> I believe the pattern is that if there is a subscript (list indexing)
>> operation in the generator expression, something is wrong after it is
>> compiled.
>> The program run as expected in interpreter mode.
>>
>> Hopefully this will make it easier for anybody who wants to take a
>> look at the problem.
>> Thanks,
>> /Wei
>>
>>
>> On Wed, Jan 22, 2014 at 11:39 AM, Wei Zhang <ndrzmansn at gmail.com> wrote:
>>> Hi,
>>>
>>> The error log was dropped by the mailing list.
>>> I uploaded it to here:
>>> https://db.tt/SnWrKZ3I
>>>
>>> Thanks,
>>> /Wei
>>>
>>>
>>> On Tue, Jan 21, 2014 at 7:41 PM, Wei Zhang <ndrzmansn at gmail.com> wrote:
>>>> Hi,
>>>>
>>>> I keep ran into the same crash when I try run a couple of benchmarks on ZipPy.
>>>>
>>>> The benchmarks that I have problem with are Python generator
>>>> intensive, which relies heavily on MaterializedFrames.
>>>> I believe it has something to do with compiled code that accesses
>>>> MaterializedFrame.
>>>> Sometime, com.oracle.truffle.api.impl.DefaultMaterializedFrame::setInt
>>>> shows up in the error message.
>>>>
>>>> The error message:
>>>>
>>>> #
>>>> # A fatal error has been detected by the Java Runtime Environment:
>>>> #
>>>> #  SIGSEGV (0xb) at pc=0x0000000107a06c0b, pid=40193, tid=6403
>>>> #
>>>> # JRE version: Java(TM) SE Runtime Environment (7.0_45-b18) (build 1.7.0_45-b18)
>>>> # Java VM: OpenJDK 64-Bit Server VM (25.0-b63-internal mixed mode
>>>> bsd-amd64 compressed oops)
>>>> # Problematic frame:
>>>> # J -1 Graal com.oracle.graal.truffle.OptimizedCallTarget.executeHelper(Lcom/oracle/truffle/api/frame/PackedFrame;Lcom/oracle/truffle/api/Arguments;)Ljava/lang/Object;
>>>> (22 bytes) @ 0x0000000107a06c0b [0x0000000107a06800+0x40b]
>>>> #
>>>> # Failed to write core dump. Core dumps have been disabled. To enable
>>>> core dumping, try "ulimit -c unlimited" before starting Java again
>>>> #
>>>> # An error report file with more information is saved as:
>>>> # /Users/zwei/Workspace/zippy/hs_err_pid40193.log
>>>> #
>>>> # If you would like to submit a bug report, please visit:
>>>> #   http://bugreport.sun.com/bugreport/crash.jsp
>>>> #
>>>>
>>>> The error log is attached.
>>>>
>>>> The problem can be reproduced with this command:
>>>> ./mx.sh --vm server python
>>>> graal/edu.uci.python.benchmark/src/benchmarks/bm-ai.py @-esa @-ea
>>>>
>>>> The latest commits of zippy can be pulled from:
>>>> ssh://hg@bitbucket.org/ssllab/zippy
>>>>
>>>> I'm not sure what would be the best way to debug this from my side,
>>>> since it went through the entire compilation phases and crashed at
>>>> runtime.
>>>> Does anybody has experienced the similar problem?
>>>> Any help is appreciated.
>>>> Thanks,
>>>>
>>>> /Wei
>
>
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