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

[David Holmes]

I agree with Tom, -XX flags should be validated in arguments.cpp if 
practical, and errors should be reported in a consistent way. If you 
want this to be fatal you could add a verify_range check for it in 
check_vm_args_consistency; else generate a warning and use the default 
value. (You might need to be careful about the placement of the check 
and be sure no other flags depend on this flag's value.)

David Holmes

Tom Rodriguez said the following on 07/28/10 04:49:
> 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
> 
> 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:
>> http://cr.openjdk.java.net/~ptisnovs/StackShadowPagesCheck/
>>
>> When -XX:StackShadowPages is set to negative integer or zero value, JVM segfaulted on Linux and, according to http://bugs.sun.com/view_bug.do?bug_id=6885308, 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 (http://bugs.sun.com/view_bug.do?bug_id=6885308) 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
>>
>