diff --git a/petsc-use_int64_t_with_mpiuni.patch b/petsc-use_int64_t_with_mpiuni.patch
new file mode 100644
index 0000000..e63e3d6
--- /dev/null
+++ b/petsc-use_int64_t_with_mpiuni.patch
@@ -0,0 +1,47 @@
+From ab86aa04d4d69fee965a3829143bef835b6ec081 Mon Sep 17 00:00:00 2001
+From: Satish Balay <balay@mcs.anl.gov>
+Date: Tue, 6 Feb 2024 15:17:17 -0600
+Subject: [PATCH] petsc64: use int64_t with mpiuni [in sync with metis]
+
+---
+ include/petsc/mpiuni/mpi.h | 1 +
+ include/petscsystypes.h    | 4 ++--
+ 2 files changed, 3 insertions(+), 2 deletions(-)
+
+diff --git a/include/petsc/mpiuni/mpi.h b/include/petsc/mpiuni/mpi.h
+index ea27c6628f4..d51a924e089 100644
+--- a/include/petsc/mpiuni/mpi.h
++++ b/include/petsc/mpiuni/mpi.h
+@@ -229,6 +229,7 @@ typedef int MPI_Datatype;
+ #define MPI_INT8_T        (5 << 20 | 1 << 8 | (int)sizeof(int8_t))
+ #define MPI_INT16_T       (5 << 20 | 1 << 8 | (int)sizeof(int16_t))
+ #define MPI_INT32_T       (5 << 20 | 1 << 8 | (int)sizeof(int32_t))
++#define MPI_INT64_T       (5 << 20 | 1 << 8 | (int)sizeof(int64_t))
+ 
+ #define MPI_UNSIGNED_SHORT     (5 << 20 | 1 << 8 | (int)sizeof(unsigned short))
+ #define MPI_UNSIGNED           (5 << 20 | 1 << 8 | (int)sizeof(unsigned))
+diff --git a/include/petscsystypes.h b/include/petscsystypes.h
+index 86f7dba1c33..6e4d549bbe6 100644
+--- a/include/petscsystypes.h
++++ b/include/petscsystypes.h
+@@ -253,7 +253,7 @@ M*/
+   #endif
+ #endif
+ 
+-#if defined(PETSC_HAVE_STDINT_H) && defined(PETSC_HAVE_INTTYPES_H) && defined(PETSC_HAVE_MPI_INT64_T) /* MPI_INT64_T is not guaranteed to be a macro */
++#if defined(PETSC_HAVE_STDINT_H) && defined(PETSC_HAVE_INTTYPES_H) && (defined(PETSC_HAVE_MPIUNI) || defined(PETSC_HAVE_MPI_INT64_T)) /* MPI_INT64_T is not guaranteed to be a macro */
+ typedef int64_t PetscInt64;
+ 
+   #define PETSC_INT64_MIN INT64_MIN
+@@ -300,7 +300,7 @@ enum {
+ #define PETSC_MAX_INT    PETSC_INT_MAX
+ #define PETSC_MAX_UINT16 65535
+ 
+-#if defined(PETSC_HAVE_STDINT_H) && defined(PETSC_HAVE_INTTYPES_H) && defined(PETSC_HAVE_MPI_INT64_T) /* MPI_INT64_T is not guaranteed to be a macro */
++#if defined(PETSC_HAVE_STDINT_H) && defined(PETSC_HAVE_INTTYPES_H) && (defined(PETSC_HAVE_MPIUNI) || defined(PETSC_HAVE_MPI_INT64_T)) /* MPI_INT64_T is not guaranteed to be a macro */
+   #define MPIU_INT64     MPI_INT64_T
+   #define PetscInt64_FMT PRId64
+ #elif (PETSC_SIZEOF_LONG_LONG == 8)
+-- 
+GitLab
+
diff --git a/petsc.spec b/petsc.spec
index f9da141..4998bce 100644
--- a/petsc.spec
+++ b/petsc.spec
@@ -318,6 +318,9 @@ Patch4:  %{name}-3.19.4-fix_metis64.patch
 Patch6:  %{name}-3.14.1-fix_pkgconfig_file.patch
 Patch7:  %{name}-3.17.0-avoid_fake_MKL_detection.patch
 
+# https://gitlab.com/petsc/petsc/-/issues/1542
+Patch8:  %{name}-use_int64_t_with_mpiuni.patch
+
 %if %{with superlu}
 BuildRequires: SuperLU-devel >= 5.2.0
 %endif
@@ -606,6 +609,7 @@ popd
 pushd %{name}-%{version}
 %patch -P 0 -p0 -b .backup
 %patch -P 6 -p1 -b .backup
+%patch -P 8 -p1 -b .backup
 popd
 
 %if %{with openmpi}