Integrated: 8352112: [ubsan] hotspot/share/code/relocInfo.cpp:130:37: runtime error: applying non-zero offset 18446744073709551614 to null pointer

[Vladimir Kozlov]

On Tue, 18 Mar 2025 18:35:06 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

> Before [JDK-8343789](https://bugs.openjdk.org/browse/JDK-8343789) `relocation_begin()` was never null even when there was no relocations - it pointed to the beginning of constant or code section in such case. It was used by relocation code to simplify code and avoid null checks.
> With that fix `relocation_begin()` points to address in `CodeBlob::_mutable_data` field which could be `nullptr` if there is no relocation and metadata.
> 
> There easy fix is to avoid `nullptr` in `CodeBlob::_mutable_data`. We could do that similar to what we do for `nmethod::_immutable_data`: [nmethod.cpp#L1514](https://github.com/openjdk/jdk/blob/master/src/hotspot/share/code/nmethod.cpp#L1514).
> 
> Tested tier1-4, stress, xcomp. Verified with failed tests listed in bug report.

This pull request has now been integrated.

Changeset: 22182f71
Author:    Vladimir Kozlov <kvn at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/22182f71ed520150b1ee05e5b788ecddfb0a6508
Stats:     9 lines in 1 file changed: 5 ins; 0 del; 4 mod

8352112: [ubsan] hotspot/share/code/relocInfo.cpp:130:37: runtime error: applying non-zero offset 18446744073709551614 to null pointer

Reviewed-by: dlong, bulasevich

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PR: https://git.openjdk.org/jdk/pull/24102