On Thu, 28 Aug 2025 15:10:03 GMT, Aleksey Shipilev <sh...@openjdk.org> wrote:
>> See the bug for more investigation. >> >> The symptom of the problem is apparent `SIGSEGV` in `dlerror`. We were able >> to debug it to older glibc issue, which makes `dlerror` not thread-safe when >> pthreads are not yet loaded. This bug seems to uniquely affect custom >> launchers. We figured this is because custom launchers are not linked with >> `pthread`. JLI seems to be avoiding this issue, because it does link with >> `pthread`. Therefore the fix on the JDK side is to always link custom >> launchers with `pthread`. >> >> Reproducing the issue is a bit awkward. It requires compiling with older GCC >> (7.3.1 in my case), so that `libsimdsort` would not expose `avx2_sort` >> symbol, so that compiler stub initialization sequence would get its own >> erroneous `dlerror`, which would conflict inside of glibc. The compilations >> with newer GCC (10, at very least) are not exposed to this. This is why the >> issue is so elusive. But now that we understand it, we know this is a >> ticking time bomb that can fire at any time in the future, once any >> concurrent thread inside of VM gets a non-zero `dlerror` for whatever reason. >> >> Additional testing: >> - [x] Linux AArch64 server fastdebug, `sun/management/jmxremote`, 100x, no >> failures >> - [ ] Linux AArch64 server fastdebug, `tools/jpackage`, 20x, no failures >> - [x] Linux AArch64 server fastdebug, `jdk_all`, no failures > > Aleksey Shipilev has updated the pull request with a new target base due to a > merge or a rebase. The incremental webrev excludes the unrelated changes > brought in by the merge/rebase. The pull request contains four additional > commits since the last revision: > > - Broader pthread linkage for all JDK jtreg executables, similar to how > Hotspot jtreg executables do it > - Merge branch 'master' into JDK-8345810-custom-launcher-dlerror > - Change to LIB* variables > - Fix Doing the same as hotspot looks good. ------------- Marked as reviewed by dholmes (Reviewer). PR Review: https://git.openjdk.org/jdk/pull/26978#pullrequestreview-3167095097
