[Buildroot] [git commit branch/2025.08.x] support/testing: TestZfsUclibc: use internal backend for uClibc-ng toolchain

[Thomas Perale]

commit: https://git.buildroot.net/buildroot/commit/?id=5ceb38f69299113765a5c1c5f10e75a5edd0b511
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2025.08.x

As reported on the mailing list [1] while investigating the
TestZfsUclibc Gitlab-CI failure, the python 3.13 interpreter itsef
segfault at runtime:

  Fatal Python error: _PyThreadState_Attach: non-NULL old thread state
  Python runtime state: preinitialized
  Thread 0xSegmentation fault

This issue is related to the python 3.13 version bump [2] were several
internal changes were added [3] to support PEP 703 [4].
PEP 793 is about CPython’s global interpreter lock (“GIL”) removal
for multi-threads support that requires a working C11 "thread_local"
for thread-local storage [5].

The new uclibc-ng 1.0.55 release contains a fix for this issue [6].
This version is included in Buildroot commit [7].

Since the prebuilt Bootling aarch64 uclibc stable 2025.08-1 is based
on previous uClibc-ng release (1.0.54) we have to use the internal
toolchain backend to build a new uClibc-ng toolchain using uclibc-ng
1.0.55. Note: the toolchain config defined in this commit reflects
the options enabled in the Bootling aarch64 uclibc external
toolchains.

Fixes:
https://gitlab.com/buildroot.org/buildroot/-/jobs/11271124859 (TestZfsUclibc)

[1] https://lore.kernel.org/buildroot/7a4d245d-1556-43c9-8997-6b1f791afbfe@gmail.com/ (TestZfsUclibc)
[2] https://gitlab.com/buildroot.org/buildroot/-/commit/d63e207eb869063f82c867658676c2903beb08cb
[3] https://github.com/python/cpython/commit/6e97a9647ae028facb392d12fc24973503693bd6
[4] https://peps.python.org/pep-0703/
[5] https://gcc.gnu.org/onlinedocs/gcc-15.1.0/gcc/Thread-Local.html
[6] https://github.com/wbx-github/uclibc-ng/commit/94c1297d52263e20cd9715601afa37f49d008d93
[7] https://gitlab.com/buildroot.org/buildroot/-/commit/5250bba8e5b1aaeb58977baf1d91e2be66656476

Cc: José Luis Salvador Rufo <salvador.joseluis at gmail.com>
Tested-by: José Luis Salvador Rufo <salvador.joseluis at gmail.com>
Cc: Waldemar Brodkorb <wbx at openadk.org>
Signed-off-by: Romain Naour <romain.naour at smile.fr>
[Julien:
 - add link to buildroot commit updating uclibc-ng to 1.0.55
 - add a note in the commit log about the toolchain config
]
Signed-off-by: Julien Olivain <ju.o at free.fr>
(cherry picked from commit 5208b7a1bde348c60a40ca6a62526d95a9ce93f6)
Signed-off-by: Thomas Perale <thomas.perale at mind.be>
---
 support/testing/tests/package/test_zfs.py | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/support/testing/tests/package/test_zfs.py b/support/testing/tests/package/test_zfs.py
index 1b907ac4de..c218cc36a8 100644
--- a/support/testing/tests/package/test_zfs.py
+++ b/support/testing/tests/package/test_zfs.py
@@ -74,9 +74,18 @@ class TestZfsGlibc(TestZfsBase):
 
 
 class TestZfsUclibc(TestZfsBase):
-    config = TestZfsBase.config + \
+    # The Bootling aarch64 uclibc stable 2025.08-1 needs to be
+    # rebuild with uClibc-ng 1.0.55.
+    # See: https://github.com/wbx-github/uclibc-ng/commit/94c1297d52263e20cd9715601afa37f49d008d93
+    config = TestZfsBase.config.replace('BR2_TOOLCHAIN_EXTERNAL=y\n', '')
+    config = config.replace('BR2_TOOLCHAIN_EXTERNAL_BOOTLIN=y\n', '') + \
         """
-        BR2_TOOLCHAIN_EXTERNAL_BOOTLIN_AARCH64_UCLIBC_STABLE=y
+        BR2_TOOLCHAIN_BUILDROOT_UCLIBC=y
+        BR2_KERNEL_HEADERS_5_4=y
+        BR2_TOOLCHAIN_BUILDROOT_LOCALE=y
+        BR2_PTHREAD_DEBUG=y
+        BR2_TOOLCHAIN_BUILDROOT_CXX=y
+        BR2_GCC_ENABLE_OPENMP=y
         """
 
     def test_run(self):