RFR: JDK-8187597: WrongTypeException is occurred at CLHSDB jstack after JDK-8186837
David Holmes
david.holmes at oracle.com
Tue Sep 19 03:31:22 UTC 2017
On 19/09/2017 1:19 PM, Yasumasa Suenaga wrote:
> Thanks David,
>
> BTW, can I push this change after jdk10/master is opened?
> I cannot access JPRT.
I think we'd probably prefer this to go into jdk10/hs - once it is open
- and for that you need a sponsor.
Thanks,
David
>
> Yasumasa
>
>
> 2017/09/19 午後0:08 "David Holmes" <david.holmes at oracle.com
> <mailto:david.holmes at oracle.com>>:
>
> Hi Yasumasa,
>
> On 19/09/2017 12:55 PM, Yasumasa Suenaga wrote:
>
> Thanks Chris, Robbin,
>
> I'm waiting reviewer(s) for this change.
>
>
> Reviewed.
>
> This simply reverts the change of 8185102.
>
> Thanks,
> David
> -----
>
>
> Yasumasa
>
>
> 2017/09/19 午前7:14 "Chris Plummer" <chris.plummer at oracle.com
> <mailto:chris.plummer at oracle.com>
> <mailto:chris.plummer at oracle.com
> <mailto:chris.plummer at oracle.com>>>:
>
> Hi Yasumasa,
>
> Ok, I see now that CIntegerField is just an interface, so
> it's up to
> a class to implement getValue() to fetch the field. I'm a bit
> unclear on how that part works, but from responses by
> others, it
> seems this is ok.
>
> I've run all the tests I can find that use jstack or jhsdb,
> and the
> assert was not triggered. Probably need to have a NMethod
> on the
> stack to trigger the code you are fixing.
>
> thanks,
>
> Chris
>
>
> On 9/17/17 1:13 AM, Yasumasa Suenaga wrote:
>
> Hi Chris,
>
> I've tested this issue on Fedora 26 x86_64.
> I think we can sue CIntegerField at this point because
> CIntegerField is not specialized for various int size [1].
> In fact, CIntegerField had been used at this point [2],
> and HSDB
> worked fine.
>
>
> Thanks,
>
> Yasumasa
>
>
> [1]
> http://hg.openjdk.java.net/jdk10/master/file/fd36993f7bf5/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/types/CIntegerField.java#l29
> <http://hg.openjdk.java.net/jdk10/master/file/fd36993f7bf5/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/types/CIntegerField.java#l29>
>
> <http://hg.openjdk.java.net/jdk10/master/file/fd36993f7bf5/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/types/CIntegerField.java#l29
> <http://hg.openjdk.java.net/jdk10/master/file/fd36993f7bf5/src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/types/CIntegerField.java#l29>>
> [2]
> http://hg.openjdk.java.net/jdk10/master/rev/cbfdbefc6ea3
> <http://hg.openjdk.java.net/jdk10/master/rev/cbfdbefc6ea3>
>
> <http://hg.openjdk.java.net/jdk10/master/rev/cbfdbefc6ea3
> <http://hg.openjdk.java.net/jdk10/master/rev/cbfdbefc6ea3>>
>
>
> On 2017/09/17 3:58, Chris Plummer wrote:
>
> Hi Yasumasa,
>
> Is this on a 32-bit system? I don't see how you could
> otherwise call getCIntegerField() on a long type.
> jlong is
> always 64-bit and long is (generally) 32-bit on 32-bit
> systems, and 64-bit on 64-bit systems, at least
> that seems
> to be the case with linux.
>
> From what I can see, _stack_traversal_mark is now
> the only
> long type in vmStructs.cpp. I don't know that we have a
> mechanism to safely fetch it on both 32-bit and
> 64-bit systems.
>
> _stack_traversal_mark seems to be a long because
> _traversals
> is also a long.
>
> static long
> _traversals; //
> Stack scan count, also sweep ID.
>
> This too might be considered a bug. I'm not sure
> why you
> would want the size of this field to vary between
> 32-bit and
> 64-bit systems (adding compiler-dev to help answer
> that).
>
> So, while I would agree that your fix is generally
> in the
> right direction, I think we first need to revisit
> the use of
> long for these fields. If they can be changed to an
> int,
> then your fix is correct (pending the changes to
> int). If
> not, then maybe we need getCLongField() support.
>
> And lastly, we really should have a test to detect
> this bug.
> Maybe we already do, and it is failing but is going
> unnoticed for some reason. I'll try to look into
> that some
> more on Monday.
>
> thanks,
>
> Chris
>
> On 9/16/17 5:20 AM, Yasumasa Suenaga wrote:
>
> Hi all,
>
> I tried to get thread dump via jstack command
> on CLHSDB.
> But it was failed as below:
>
> ```
> Caused by:
> sun.jvm.hotspot.types.WrongTypeException:
> field "_stack_traversal_mark" in type nmethod
> is not of
> type jlong, but instead of type long
> at
>
> jdk.hotspot.agent/sun.jvm.hotspot.types.basic.BasicType.getField(BasicType.java:206)
> at
>
> jdk.hotspot.agent/sun.jvm.hotspot.types.basic.BasicType.getField(BasicType.java:212)
> at
>
> jdk.hotspot.agent/sun.jvm.hotspot.types.basic.BasicType.getJLongField(BasicType.java:249)
> at
>
> jdk.hotspot.agent/sun.jvm.hotspot.code.NMethod.initialize(NMethod.java:108)
> at
>
> jdk.hotspot.agent/sun.jvm.hotspot.code.NMethod.access$000(NMethod.java:35)
> at
>
> jdk.hotspot.agent/sun.jvm.hotspot.code.NMethod$1.update(NMethod.java:81)
>
> at
>
> jdk.hotspot.agent/sun.jvm.hotspot.runtime.VM.registerVMInitializedObserver(VM.java:451)
> at
>
> jdk.hotspot.agent/sun.jvm.hotspot.code.NMethod.<clinit>(NMethod.java:79)
> ... 23 more
> ```
>
> I think this exception is caused by JDK-8186837.
> This changeset has changed the type of
> `nmethod::_stack_traversal_mark` to `long` from
> `jlong`.
>
> SA should follow this change.
>
> I uploaded a webrev for this issue. This webrev is
> generated from consolidated repo (jdk10/master).
> Could you review it?
>
> http://cr.openjdk.java.net/~ysuenaga/JDK-8187597/webrev.00/
> <http://cr.openjdk.java.net/~ysuenaga/JDK-8187597/webrev.00/>
>
> <http://cr.openjdk.java.net/~ysuenaga/JDK-8187597/webrev.00/
> <http://cr.openjdk.java.net/~ysuenaga/JDK-8187597/webrev.00/>>
>
>
> I cannot access JPRT. So I need reviewer.
>
>
> Thanks,
>
> Yasumasa
>
>
>
>
>
>
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