Need reviewers for changes in JVM initialization code (added check for -XX:StackShadowPages option)

Coleen Phillimore coleen.phillimore at
Tue Aug 17 13:17:40 PDT 2010

Yes, I agree they should stay intx.  Thank you for the change.  It looks 
fine to me.  If you update the patch, I will push it through JPRT.  Let 
me know when it is ready.

Paul Hohensee wrote:
>  Leave them as intx, imo.  Their high bound value isn't anywhere near 
> maxint,
> and if you change them to uintx you'll have to cast them to intx for the
> calls to verify_min_value.  Plus there's some places where their 
> values are
> assigned to ints that would have to be changed.
> Also, pls use INTX_FORMAT instead of UINTX_FORMAT in verify_min_value.
> Paul
> On 8/17/10 3:50 PM, Tom Rodriguez wrote:
>> On Aug 6, 2010, at 7:05 AM, Pavel Tisnovsky wrote:
>>> Tom Rodriguez wrote:
>>>> I think you could put this check into arguments.cpp since I all 
>>>> platforms would require a positive number for the 
>>>> StackShadowPages.  The same should be true of StackRedPages and 
>>>> StackYellowPages.  Actually they all should be required to greater 
>>>> than 0 I think.  Other than that I don't see other obvious 
>>>> constraints on the values.  That bug report doesn't really show 
>>>> other problematic values, though I'm not sure I follow the point of 
>>>> the guarantee that's failing either.  What does the min stack size 
>>>> have to do with the number of guard pages?  I would expect it to be 
>>>> checking against ThreadStackSize and returning an error if it was 
>>>> too small like the other places that check against TheadStackSize.
>>>> tom
>>> Hi Tom,
>>> I've added check for all Stack*Pages parameters to arguments.cpp. Can
>>> you please review the changes?
>>> Is there any reason why Stack*Pages parameters are of type int and not
>>> unsigned int? I'm able to change its types (these variables are
>>> generated by macro which accepts type as one of its parameter) but I'm
>>> not sure if it would be correct in all cases.
>> Would someone from runtime want to comment on this?  It seems ok to 
>> me.  Changing to uintx would also be ok but it might require other 
>> uses to be converted to unsigned as well.  I'd probably just leave it 
>> alone myself.
>> tom
>>> Cheers
>>> Pavel
>>>> On Jul 27, 2010, at 8:15 AM, Pavel Tisnovsky wrote:
>>>>> Hi all,
>>>>> can anybody please review two quite simple changes in JVM 
>>>>> initialization code? Webrev is available at:
>>>>> When -XX:StackShadowPages is set to negative integer or zero 
>>>>> value, JVM segfaulted on Linux and, according to 
>>>>>, hangs up on 
>>>>> Solaris (although I only check this issue on Linux)
>>>>> I also would like to add more check for -XX:StackRedPages, 
>>>>> -XX:StackShadowPages and -XX:StackYellowPages options to avoid 
>>>>> issue described in the bug report mentioned above 
>>>>> ( but I'm unable to 
>>>>> find relevant information about proper conditions (it may depends 
>>>>> on page sizes, VM stack size etc.). Any ideas?
>>>>> Cheers
>>>>> Pavel Tisnovsky

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