RFR (S): 8026775: nsk/jvmti/RedefineClasses/StressRedefine crashes due to EXCEPTION_ACCESS_VIOLATION

[Mikael Vidstedt]

Please review:

Bug: https://bugs.openjdk.java.net/browse/JDK-8026775
webrev: http://cr.openjdk.java.net/~mikael/webrevs/8026775/webrev.01/webrev/

Exec summary:

The stack banging code in the UncommonTrapBlob is not pre-touching all 
the stack shadow pages as it should. The result is that under some 
circumstances it may leave unmapped "holes" on the stack, and when a 
compiled method later touches a stack page on the other side of the hole 
Windows will raise an exception because it requires all stack pages to 
be touched/mapped in order.


Details:

The code in MacroAssembler::bang_stack_size() is supposed to generate 
code which touches enough stack pages to make room for the interpreter 
frame for the deoptimized method and then touch an additional 
StackShadowPages pages. However, the code fails to do this because:

a) it touches the same page twice (the last page touched in the first 
loop is the exact same address touched the first time in the second 
loop), and
b) it doesn't loop all the way up to *and including* StackShadowPages 
(the "-1" is incorrect, and so is the less than)

The corresponding code in 
AbstractInterpreterGenerator::bang_stack_shadow_pages() touches all 
pages from 1 page below sp all the way down to StackShadowPages below sp 
*inclusive*. The UncommonTrapBlob is supposed to mimic that exact same 
behavior.

Cheers,
Mikael