(9) RFR: 8064815 Zero+PPC64: Stack overflow when running Maven

[Vladimir Kozlov]

I mean next guarantee:

   guarantee(Thread::current() == thread, "should run in the same thread");

otherwise 'thread->stack_base() - (address) &stack_used' will give wrong result if threads are different.

Thanks,
Vladimir

On 11/17/14 9:00 AM, Severin Gehwolf wrote:
> Hi Vladimir,
>
> On Fri, 2014-11-14 at 09:25 -0800, Vladimir Kozlov wrote:
>> So this code assumes that 'stack_used' local is allocated on stack and
>> uses its address to calculated used space. But where is a guarantee
>> that passed 'thread' is the current thread?
>
> Yes, in src/cpu/zero/vm/stubGenerator_zero.cpp the stack is alloca'ed. I
> don't think there is currently a guarantee that the passed thread is the
> current thread. What kind of guarantee are you looking for? Any
> suggestions?
>
> Cheers,
> Severin
>
>> Thanks,
>> Vladimir
>>
>> On 11/14/14 5:46 AM, Volker Simonis wrote:
>>> Hi Severin,
>>>
>>> I can sponsor this change if we get one more review.
>>>
>>> The only comment I have is that in ZeroStack::suggest_size() there
>>> doesn't seem to be a handling for the potentially negative values
>>> returned by ZeroStack::abi_stack_available().
>>>
>>> Regards,
>>> Volker
>>>
>>>
>>> On Fri, Nov 14, 2014 at 2:18 PM, Severin Gehwolf <sgehwolf at redhat.com> wrote:
>>>> Hi,
>>>>
>>>> Could I please get a review and sponsor for the following fix:
>>>>
>>>> bug: https://bugs.openjdk.java.net/browse/JDK-8064815
>>>> webrev:
>>>> https://jerboaa.fedorapeople.org/bugs/openjdk/JDK-8064815/webrev.0/
>>>>
>>>> When running Maven ("mvn") on a Zero variant build on PPC/PPC64 hardware
>>>> it throws a StackOverflowError. This is because the stack bound
>>>> calculation does not account for red and yellow pages.
>>>>
>>>> The bug has a slightly different patch attached. The changes to
>>>> hotspot/src/os/linux/vm/os_linux.cpp aren't needed for this bug.
>>>>
>>>> Testing done: A Zero variant build of OpenJDK 9 on PPC/PPC64 throws
>>>> StackOverflowError without this fix and works fine with this fix
>>>> applied.
>>>>
>>>> Note that this problem seems to surface on architectures where pages are
>>>> large. PPC is one such instance. Page size there is 64KB and Zero
>>>> initially sets its minimal stack allowance to 64KB (one page),
>>>> src/os_cpu/linux_zero/vm/os_linux_zero.cpp. In os::init_2 this gets
>>>> potentially increased if min_stack_allowed is small. The case on PPC
>>>> Zero.
>>>>
>>>> However, then later at runtime the calculation of available stack is
>>>> wrong since it does not account for red and yellow pages. Thus it thinks
>>>> there is too little stack available where in fact more stack is
>>>> available.
>>>>
>>>> Thanks,
>>>> Severin
>>>>
>
>
>