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

[Vladimir Kozlov]

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?

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
>>