[8u] RFR: JFR possible generate same symbol/cstring id for different symbol/string

[Mario Torre]

Hi Kalinshi,

Can we please keep the reviews all in one thread? It's rather
difficult to reconstruct the review as the messages seem to be
scattered across multiple replies and threads.

Cheers,
Mario

Il giorno lun 19 ott 2020 alle ore 14:31 kalinshi(施慧)
<kalinshi at tencent.com> ha scritto:
>
> Hi All,
>
> Please help review this JFR issue again in 8u. This problem can be easily reproduced with CDS and reproduce steps in JBS.
>
> Fix includes:
> 1.  Remove map_symbol/map_cstring methods with only hashcode, all lookup must pass symbol or cstring with hashcode.
> 2.  In JfrSymbolId::equals methods, compare symbol reference or cstring contents when hashcodes are same.
> 3.  Rebuild anonymous klass cstring when search its sctring entry id.
>
> JBS: https://bugs.openjdk.java.net/browse/JDK-8253837
> Webrev: http://cr.openjdk.java.net/~hshi/8253837/webrev_2/
>
>
> Early review threads https://mail.openjdk.java.net/pipermail/jdk8u-dev/2020-October/012754.html  https://mail.openjdk.java.net/pipermail/jdk8u-dev/2020-October/012782.html
> In early discussion, jdk11u fix equals method in https://bugs.openjdk.java.net/browse/JDK-8231081, major concern is if the entire change need be backported.
> Actually partial change is included such as changes in mark_unsafe_anonymous_klass_name and create_unsafe_anonymous_klass_symbol.
> It might not easy to backport it cleanly at this time.
>
>
> Regards
> Hui



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