Fix signed overflow issue in npy_gcd for INT_MIN on s390x

Resolves: RHEL-193000

fix-signed-overflow-s390x.patch

@@ -0,0 +1,70 @@
+From 80071371601233408b4d919dfe7cc05cfee93d02 Mon Sep 17 00:00:00 2001
+From: AnkitAhlawat <Ankit.Ahlawat@ibm.com>
+Date: Thu, 30 Apr 2026 19:18:10 +0530
+Subject: [PATCH] BUG: Fix signed overflow issue in npy_gcd for INT_MIN on
+ s390x (#31360)
+
+This PR fixes signed overflow issue in npy_gcd when one of the inputs is the minimum value of a signed integer type (INT_MIN) on s390x architecture.
+
+issue was the expression a < 0 ? -a : a in npy_math_internal.h.src causes undefined behavior when a = INT_MIN because negating INT_MIN overflows a signed integer on s390x. i see it is working fine with other arch so fix only provided to s390x
+---
+ numpy/_core/src/npymath/npy_math_internal.h.src | 11 ++++++++++-
+ numpy/_core/tests/test_umath.py                 | 12 ++++++++----
+ 2 files changed, 18 insertions(+), 5 deletions(-)
+
+diff --git a/numpy/_core/src/npymath/npy_math_internal.h.src b/numpy/_core/src/npymath/npy_math_internal.h.src
+index 2f38497..787f7e6 100644
+--- a/numpy/_core/src/npymath/npy_math_internal.h.src
++++ b/numpy/_core/src/npymath/npy_math_internal.h.src
+@@ -650,12 +650,21 @@ npy_lcm@c@(@type@ a, @type@ b)
+  *
+  * #type = (npy_int, npy_long, npy_longlong)*2#
+  * #c = (,l,ll)*2#
++ * #utype = (npy_uint, npy_ulong, npy_ulonglong)*2#
+  * #func=gcd*3,lcm*3#
+  */
+ NPY_INPLACE @type@
+ npy_@func@@c@(@type@ a, @type@ b)
+ {
+-    return npy_@func@u@c@(a < 0 ? -a : a, b < 0 ? -b : b);
++    /*
++     * Cast to unsigned to avoid overflow when negating minimum signed value.
++     * For negative values, cast to unsigned first, then apply negation in
++     * unsigned arithmetic to avoid undefined behavior.
++     * This ensures correct behavior across all architectures. #31359
++     */
++    @utype@ a_abs = a < 0 ? (@utype@)(0) - (@utype@)a : (@utype@)a;
++    @utype@ b_abs = b < 0 ? (@utype@)(0) - (@utype@)b : (@utype@)b;
++    return (@type@)npy_@func@u@c@(a_abs, b_abs);
+ }
+ /**end repeat**/
+ 
+diff --git a/numpy/_core/tests/test_umath.py b/numpy/_core/tests/test_umath.py
+index 8eac236..1575dd6 100644
+--- a/numpy/_core/tests/test_umath.py
++++ b/numpy/_core/tests/test_umath.py
+@@ -4131,13 +4131,17 @@ def test_lcm_overflow(self):
+         assert_equal(np.lcm(a, b), 10 * big)
+ 
+     def test_gcd_overflow(self):
+-        for dtype in (np.int32, np.int64):
+-            # verify that we don't overflow when taking abs(x)
+-            # not relevant for lcm, where the result is unrepresentable anyway
+-            a = dtype(np.iinfo(dtype).min)  # negative power of two
++        # verify that we don't overflow when taking abs(x) for INT_MIN
++        # this was undefined behavior that manifested on s390x with GCC 11.5
++        for dtype in (np.int8, np.int16, np.int32, np.int64):
++            a = dtype(np.iinfo(dtype).min)  # INT_MIN
+             q = -(a // 4)
++            # Test with INT_MIN as first argument
+             assert_equal(np.gcd(a,  q * 3), q)
+             assert_equal(np.gcd(a, -q * 3), q)
++            # Test with INT_MIN as second argument
++            assert_equal(np.gcd(q * 3,  a), q)
++            assert_equal(np.gcd(-q * 3, a), q)
+ 
+     def test_decimal(self):
+         from decimal import Decimal
+-- 
+2.54.0
+

python3.14-numpy.spec

@@ -48,6 +48,11 @@ Patch:          coverity-fixes.patch
 # Sent upstream: https://github.com/numpy/numpy/pull/31333
 Patch:          fix-test_validate_transcendentals-x86_64.patch
 
+# Fix signed overflow issue in npy_gcd for INT_MIN on s390x
+# Resolved upstream:
+# https://github.com/numpy/numpy/pull/31360
+Patch:          fix-signed-overflow-s390x.patch
+
 BuildRequires:  python%{python3_pkgversion}-devel
 BuildRequires:  gcc-gfortran gcc gcc-c++
 BuildRequires:  lapack-devel
@@ -246,7 +251,8 @@ export PYTHONPATH=%{buildroot}%{python3_sitearch}
 * Tue Jul 07 2026 Charalampos Stratakis <cstratak@redhat.com> - 2.3.4-2
 - Fix issues identified via Coverity static analysis
 - Fix test_validate_transcendentals skip to match SVML dispatch
-- Fixes: RHEL-193002, RHEL-193001
+- Fix signed overflow issue in npy_gcd for INT_MIN on s390x
+- Fixes: RHEL-193002, RHEL-193001, RHEL-193000
 
 * Thu Oct 23 2025 Tomáš Hrnčiar <thrnciar@redhat.com> - 2.3.4-1
 - Initial import