diff --git a/lib/common/mock.c b/lib/common/mock.c
index 6a57fa0f7a..b55b780cb6 100644
--- a/lib/common/mock.c
+++ b/lib/common/mock.c
@@ -1,52 +1,57 @@
 /*
- * Copyright 2021 the Pacemaker project contributors
+ * Copyright 2021-2022 the Pacemaker project contributors
  *
  * The version control history for this file may have further details.
  *
  * This source code is licensed under the GNU Lesser General Public License
  * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
  */
 
 #include <stdlib.h>
 #include <sys/utsname.h>
 
 #include "mock_private.h"
 
 /* This file is only used when running "make check".  It is built into
  * libcrmcommon_test.a, not into libcrmcommon.so.  It is used to support
  * constructing mock versions of library functions for unit testing.
  *
  * Each unit test will only ever want to use a mocked version of one or two
  * library functions.  However, we need to mark all the mocked functions as
  * wrapped (with -Wl,--wrap= in the LDFLAGS) in libcrmcommon_test.a so that
  * all those unit tests can share the same special test library.  The unit
  * test then defines its own wrapped function.  Because a unit test won't
  * define every single wrapped function, there will be undefined references
  * at link time.
  *
  * This file takes care of those undefined references.  It defines a
  * wrapped version of every function that simply calls the real libc
  * version.  These wrapped versions are defined with a weak attribute,
  * which means the unit tests can define another wrapped version for
  * unit testing that will override the version defined here.
  *
  * IN SUMMARY:
  *
  * - Define two functions for each function listed in WRAPPED in mock.mk.
  *   One function is a weakly defined __wrap_X function that just calls
  *   __real_X.
  * - Add a __real_X and __wrap_X function prototype for each function to
  *   mock_private.h.
  * - Each unit test defines its own __wrap_X for whatever function it's
  *   mocking that overrides the version here.
  */
 
+void *__attribute__((weak))
+__wrap_calloc(size_t nmemb, size_t size) {
+    return __real_calloc(nmemb, size);
+}
+
 char *__attribute__((weak))
 __wrap_getenv(const char *name) {
     return __real_getenv(name);
 }
 
 int __attribute__((weak))
 __wrap_uname(struct utsname *buf) {
     return __real_uname(buf);
 }
diff --git a/lib/common/mock.mk b/lib/common/mock.mk
index 9fcdbccf8e..c4817717ac 100644
--- a/lib/common/mock.mk
+++ b/lib/common/mock.mk
@@ -1,2 +1,2 @@
-WRAPPED = getenv uname
+WRAPPED = calloc getenv uname
 WRAPPED_FLAGS = $(foreach fn,$(WRAPPED),-Wl,--wrap=$(fn))
diff --git a/lib/common/mock_private.h b/lib/common/mock_private.h
index 8b455ec40b..4f33f21817 100644
--- a/lib/common/mock_private.h
+++ b/lib/common/mock_private.h
@@ -1,23 +1,27 @@
 /*
- * Copyright 2021 the Pacemaker project contributors
+ * Copyright 2021-2022 the Pacemaker project contributors
  *
  * The version control history for this file may have further details.
  *
  * This source code is licensed under the GNU Lesser General Public License
  * version 2.1 or later (LGPLv2.1+) WITHOUT ANY WARRANTY.
  */
 
 #ifndef MOCK_PRIVATE__H
 #  define MOCK_PRIVATE__H
 
+#include <stdlib.h>
 #include <sys/utsname.h>
 
 /* This header is for the sole use of libcrmcommon_test. */
 
+void *__real_calloc(size_t nmemb, size_t size);
+void *__wrap_calloc(size_t nmemb, size_t size);
+
 char *__real_getenv(const char *name);
 char *__wrap_getenv(const char *name);
 
 int __real_uname(struct utsname *buf);
 int __wrap_uname(struct utsname *buf);
 
 #endif  // MOCK_PRIVATE__H