Apply patch to fix hanging test on uniprocessor machines

Resolves: RHEL-86470

tbb-2021-avoid-zero-threads.patch

@@ -0,0 +1,29 @@
+From 8c968ef74bb804200cd25fa6e078d5aabed7a5e6 Mon Sep 17 00:00:00 2001
+From: Petter Reinholdtsen <pere@debian.org>
+Date: Tue, 31 Mar 2026 10:07:49 +0200
+Subject: [PATCH] Adjusted test_lightweight to avoid zero threads in test.
+
+When the hardware only support one core, hardware_concurrency() return 1,
+which when deviced by 2 using integer division end up as 0, a useless
+number of threads.  Instead, ensure it end up as 1, while the other
+return values still end up with a sensible number by changing
+(i/2) to ((i+1)/2).
+
+This fix is related to #2027.
+---
+ test/common/graph_utils.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/test/common/graph_utils.h b/test/common/graph_utils.h
+index 26a0c0ada0..714a27f79b 100644
+--- a/test/common/graph_utils.h
++++ b/test/common/graph_utils.h
+@@ -953,7 +953,7 @@ template<typename NodeType>
+ void test_lightweight(unsigned N) {
+     test_unlimited_lightweight_execution<NodeType>(N);
+     test_limited_lightweight_execution<NodeType>(N, tbb::flow::serial);
+-    test_limited_lightweight_execution<NodeType>(N, (std::min)(std::thread::hardware_concurrency() / 2, N/2));
++    test_limited_lightweight_execution<NodeType>(N, (std::min)((std::thread::hardware_concurrency()+1) / 2, N/2));
+ 
+     test_limited_lightweight_execution_with_throwing_body<NodeType>(N, tbb::flow::serial);
+ }

tbb.spec

@@ -5,7 +5,7 @@
 Name:    tbb
 Summary: The Threading Building Blocks library abstracts low-level threading details
 Version: 2021.11.0
-Release: 7%{?dist}
+Release: 8%{?dist}
 License: Apache-2.0 AND BSD-3-Clause
 URL:     http://threadingbuildingblocks.org/
 
@@ -21,6 +21,10 @@ Patch0: tbb-2021-Werror.patch
 # Fix code that violates the strict aliasing rules.
 Patch1: tbb-2021-strict-aliasing.patch
 
+# https://github.com/uxlfoundation/oneTBB/pull/2033
+# https://issues.redhat.com/browse/RHEL-86470
+Patch3: tbb-2021-avoid-zero-threads.patch
+
 BuildRequires: cmake
 BuildRequires: gcc-c++
 BuildRequires: hwloc
@@ -187,6 +191,10 @@ ctest --output-on-failure --force-new-ctest-process
 %{python3_sitearch}/__pycache__/TBB*
 
 %changelog
+* Tue Apr 21 2026 Jonathan Wakely <jwakely@redhat.com> - 2021.11.0-8
+- Apply patch to fix hanging test on uniprocessor machines.
+  Resolves: RHEL-86470
+
 * Tue Oct 29 2024 Troy Dawson <tdawson@redhat.com> - 2021.11.0-7
 - Bump release for October 2024 mass rebuild:
   Resolves: RHEL-64018