[jdk25u-dev] RFR: 8370502: C2: segfault while adding node to IGVN worklist

[Ozan Cetin]

On Tue, 24 Feb 2026 16:17:33 GMT, Goetz Lindenmaier <goetz at openjdk.org> wrote:

>> Backporting JDK-8370502: C2: segfault while adding node to IGVN worklist. 
>> 
>> This PR backports a fix for a C2 segmentation fault that occurs when expanding an UnlockNode with a null memory projection. The fix adds a necessary null check to ensure fallthrough_memproj is valid before attempting to replace it in the IGVN worklist.
>> 
>> make run-test TEST=tier1
>> make run-test TEST=hotspot_compiler 
>> make run-test TEST=test/hotspot/jtreg/compiler/c2/TestUnlockNodeNullMemprof.java 
>> 
>> Results: 
>> [hotspot_compiler_report.html](https://github.com/user-attachments/files/25494824/hotspot_compiler_report.html)
>> [TestUnlockNodeNullMemprof_report.html](https://github.com/user-attachments/files/25494831/TestUnlockNodeNullMemprof_report.html)
>
> Hi @0zzy0sbourne 
> please backport to 26 first. removing the label in the meantime.

> Hi @GoeLin, raised a [PR](https://github.com/openjdk/jdk26u/pull/75) against 26.

@GoeLin, the fix is backported to 26.

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PR Comment: https://git.openjdk.org/jdk25u-dev/pull/304#issuecomment-3966745173