Mismatched ciMethodData in replay file.

[Tobias Hartmann]

Hi,

Thanks for reporting this, I see that you now file https://bugs.openjdk.java.net/browse/JDK-8287046.

Best regards,
Tobias

On 19.05.22 08:14, Liu, Xin wrote:
> hi,
> 
> I get a weird replay, which was generated by 17.0.3+6-LTS. I don't see
> relevant code have changed since then, so I think it is still applicable
> to the tip of HotSpot.
> 
> A customer shared the replay file
> with(https://github.com/corretto/corretto-17/issues/57#issuecomment-1130042063)
> and I am trying to reproduce his failure. it is written from
> VMError::report_and_die().
> 
> One obstacle is that weird entries of ciMethodData. eg. line
> 14130, It declares that there will 2 non-null oops followed(see '2'
> after tag 'oops'. however, one only is recorded.
> 
> ciMethodData kotlin/coroutines/jvm/internal/ContinuationImpl <init>
> (Lkotlin/coroutines/Continuation;)V 2 21538 orig 80 0 0 0 0 0 0 0 0 0 0
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 data
> 26 0x40007 0x402 0x70 0x4e9c 0x70005 0x4d55 0x0 0x7f6a5841c3c0 0xa3
> 0x7f6a5841c470 0xa4 0xc0003 0x4e9c 0x18 0x110002 0x529e 0x0 0x0 0x0 0x0
> 0x0 0x0 0x9 0x2 0x6 0x0 oops 2 7
> com/example/ProductAttRouter$withRequestLoggingContext$1 methods 0
> 
> Another mismatched entry is at line 14203. it says there are 11
> oops but only 6 are there.
> 
> Those mismatched entries leave uninitialized elements of rec->_classes
> and eventually crash ciReplay::initialize(). Have you seen them before?
> I can patch up hotspot to handle this mismatch, but I wonder how that
> happens?
> 
> ciMethodData::dump_replay_data() iterates
> _data 2 rounds. The 1st round counts them and second round dumps them.
> https://github.com/openjdk/jdk/blob/master/src/hotspot/share/ci/ciMethodData.cpp#L728
> 
> Is that possible that the underlying data get updated on the fly? This
> case is kotlin coroutine. I am not
> sure whether it is same threading environment as classic Java.
> 
> thanks,
> --lx
>