RFR: 8376284: New test serviceability/sa/TestJhsdbJstackMixedCore.java from JDK-8374482 fails on Linux Alpine

[Chris Plummer]

On Thu, 29 Jan 2026 06:20:57 GMT, Yasumasa Suenaga <ysuenaga at openjdk.org> wrote:

> TestJhsdbJstackMixedCore.java introduced in [JDK-8374482](https://bugs.openjdk.org/browse/JDK-8374482) failed on Alpine because musl-c does not provide the symbol of signal trampoline (`__restore_rt` on Linux Kernel for AMD64) as following:
> 
> 
> java.lang.RuntimeException: '<signal handler called>' missing from stdout/stderr
> at jdk.test.lib.process.OutputAnalyzer.shouldContain(OutputAnalyzer.java:253)
> at TestJhsdbJstackMixedCore.runJstackMixed(TestJhsdbJstackMixedCore.java:62)
> at TestJhsdbJstackMixedCore.main(TestJhsdbJstackMixedCore.java:74)
> at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
> at java.base/java.lang.reflect.Method.invoke(Method.java:565)
> at com.sun.javatest.regtest.agent.MainActionHelper$AgentVMRunnable.run(MainActionHelper.java:335)
> at java.base/java.lang.Thread.run(Thread.java:1516)
> 
> 
> It would success if debuginfo is installed, but it should be skipped if the symbol is not available.
> See JBS for details.

test/hotspot/jtreg/serviceability/sa/TestJhsdbJstackMixedCore.java line 71:

> 69:         // Check whether the symbol of signal trampoline is available.
> 70:         var libc = SATestUtils.getLibCPath();
> 71:         if (!SATestUtils.isSymbolAvailable(libc, "__restore_rt")) {

Do we have any reason to support the lookup of symbols not in libc? I'm just wondering if `SATestUtils.isSymbolAvailable()` should just take the symbol argument not the libc argument.

test/lib/jdk/test/lib/SA/SATestUtils.java line 272:

> 270:     /**
> 271:      * Find library file what provides address of strlen(3), then returns it as libc.
> 272:      * This method would work on Linux only.

Suggestion:

     * Find library file that provides strlen(3), then returns it as libc.
     * This method works on Linux only.

test/lib/jdk/test/lib/SA/SATestUtils.java line 300:

> 298:             var info = arena.allocate(structDLInfo);
> 299:             int result = (int)dladdr.invoke(ptrStrlen, info);
> 300:             if(result == 0){

Suggestion:

            if (result == 0) {

test/lib/jdk/test/lib/SA/SATestUtils.java line 315:

> 313:     /**
> 314:      * Find debuginfo file from the library.
> 315:      * This method would work on Linux only.

Suggestion:

     * Find debuginfo file for the library.
     * This method will work on Linux only.

test/lib/jdk/test/lib/SA/SATestUtils.java line 345:

> 343:     }
> 344: 
> 345:     private static boolean isSymbolAvailableInternal(String lib, String symbol) throws IOException {

Should `lib` be named something more like `debugInfoPath`?

test/lib/jdk/test/lib/SA/SATestUtils.java line 354:

> 352: 
> 353:     /**
> 354:      * This method would work on Linux only.

Suggestion:

     * This method will work on Linux only.

test/lib/jdk/test/lib/SA/SATestUtils.java line 356:

> 354:      * This method would work on Linux only.
> 355:      * Both "readelf" and "nm" have to be available.
> 356:      * @return true if given symbol is available on given lib.

Suggestion:

     * @return true if given symbol is available in given lib.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/29480#discussion_r2748141842
PR Review Comment: https://git.openjdk.org/jdk/pull/29480#discussion_r2748107517
PR Review Comment: https://git.openjdk.org/jdk/pull/29480#discussion_r2748164779
PR Review Comment: https://git.openjdk.org/jdk/pull/29480#discussion_r2748145164
PR Review Comment: https://git.openjdk.org/jdk/pull/29480#discussion_r2748160452
PR Review Comment: https://git.openjdk.org/jdk/pull/29480#discussion_r2748135231
PR Review Comment: https://git.openjdk.org/jdk/pull/29480#discussion_r2748143118