RFR: 8338883: Show warning when CreateCoredumpOnCrash set, but core dump will not happen [v15]

[Johan Sjölen]

On Mon, 7 Oct 2024 21:35:53 GMT, Gerard Ziemski <gziemski at openjdk.org> wrote:

>> We add a small feature, which prints a warning if user explicitly requests `CreateCoredumpOnCrash`, but it's disabled on the os level.
>> 
>> This behavior is the same as other VM features that can be turned on by runtime flags, but are unavailable. For example we show `"UseCRC32 specified, but not supported on this CPU"` if `UseCRC32` is set, but unavailable.
>> 
>> Example of output:
>> 
>> 
>> # ulimit -c 0                                                         
>> # ./build/xcode/build/jdk/bin/java -XX:+CreateCoredumpOnCrash -version
>> OpenJDK 64-Bit Server VM warning: CreateCoredumpOnCrash specified, but Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
>> openjdk version "24-internal" 2025-03-18
>> OpenJDK Runtime Environment (build 24-internal-adhoc.gerard.jdk)
>> OpenJDK 64-Bit Server VM (build 24-internal-adhoc.gerard.jdk, mixed mode, sharing)
>> 
>> # ulimit -c 1024                                                      
>> # ./build/xcode/build/jdk/bin/java -XX:+CreateCoredumpOnCrash -version
>> OpenJDK 64-Bit Server VM warning: CreateCoredumpOnCrash specified, but /cores/core.66547 (max size 512 k). To ensure a full core dump, try "ulimit -c unlimited" before starting Java again
>> openjdk version "24-internal" 2025-03-18
>> OpenJDK Runtime Environment (build 24-internal-adhoc.gerard.jdk)
>> OpenJDK 64-Bit Server VM (build 24-internal-adhoc.gerard.jdk, mixed mode, sharing)
>> 
>> # ulimit -c unlimited
>> # ./build/xcode/build/jdk/bin/java -XX:+CreateCoredumpOnCrash -version
>> openjdk version "24-internal" 2025-03-18
>> OpenJDK Runtime Environment (build 24-internal-adhoc.gerard.jdk)
>> OpenJDK 64-Bit Server VM (build 24-internal-adhoc.gerard.jdk, mixed mode, sharing)
>> 
>> 
>> 
>> 
>> 
>> Testing:
>> - passes `gtest runtime/ErrorHandling/CreateCoredumpOnCrash.java`
>> - passes MACH5 tier1,tier2,tier3,tier4,tier5
>
> Gerard Ziemski has updated the pull request incrementally with one additional commit since the last revision:
> 
>   final tweaks

Marked as reviewed by jsjolen (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/20734#pullrequestreview-2356768872