Looks good.
--alex
On 04/13/2020 11:45, Chris Plummer wrote:
Ping! Can I get one more review please.
thanks,
Chris
On 4/9/20 10:21 PM, Ioi Lam wrote:
Hi Chris,
Thanks for fixing this. It looks good to me.
- Ioi
On 4/9/20 9:44 PM, Chris Plummer wrote:
Hello,
Please review the following:
https://bugs.openjdk.java.net/browse/JDK-8235220
http://cr.openjdk.java.net/~cjplummer/8235220/webrev.00
First off, thanks to Ioi for tracking this one down and proposing the
fix.
The test is executing the clhsdb "scanoops" command, which scans the
specified heap address range looking for objects of the specified
type (or all objects if no type is specified). The test determines
the address range by first using clhsdb "universe" to get the start
and end of the eden space. scanoops then iterates over this entire
range, calling RobustOopDeterminator.oopLooksValid() on each oop as
it iterates over the range. The problem is eventually you'll end up
past the initialized part of the heap. That causes
VirtualBaseConstructor.findDynamicTypeForAddress() to return null,
resulting in throwing a WrongTypeException.
RobustOopDeterminator.oopLooksValid() should catch this exception and
return false when it happens.
The CR mentions a few different failure modes. This only fixes the
WrongTypeException failure. The NullPointerException is only on OSX
and I believe is the same as JDK-8241158 [1], which happens when
dumping the heap, so it seems probable that it is also turning up
when scanning part of the heap. I think this bug was preventing us
from ever seeing the WrongTypeException on OSX. Then there also
JDK-8230731 [2] on Windows, which seems to prevent ever seeing the
WrongTypeException on Windows.
[1] https://bugs.openjdk.java.net/browse/JDK-8241158
[2] https://bugs.openjdk.java.net/browse/JDK-8230731
thanks,
Chris
