[crac] RFR: Don't crash the VM if checkpointing fails

[Anton Kozlov]

On Wed, 29 Jun 2022 08:23:21 GMT, Volker Simonis <simonis at openjdk.org> wrote:

> Currently, if checkpointing is failing (because the `criu` executable can't be find or if `criu dump` returns an error) the JVM will crash with:
> 
> $ java -XX:+CRPrintResourcesOnCheckpoint -XX:CCheckpointTo=/tmp/crac HelloWait
> HelloWorld
> JVM: FD fd=0 type=character: details1="/dev/pts/9" OK: inherited from process env
> JVM: FD fd=1 type=character: details1="/dev/pts/9" OK: inherited from process env
> JVM: FD fd=2 type=character: details1="/dev/pts/9" OK: inherited from process env
> JVM: FD fd=3 type=regular: details1="/output/crac-dbg/images/jdk/lib/modules" OK: inherited from process env
> CR: Checkpoint ...

The change looks good. Thanks for fixing this. I was trying to optimize failure case, but at some point it apparently went out of sync with the usual path.

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Marked as reviewed by akozlov (Lead).

PR: https://git.openjdk.org/crac/pull/25