diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -10158,6 +10158,19 @@
 #define INIT_ARGP_PARSE
 #endif
 
+#if SANITIZER_INTERCEPT_CPUSET_GETAFFINITY
+INTERCEPTOR(int, cpuset_getaffinity, int level, int which, __int64_t id, SIZE_T cpusetsize, __sanitizer_cpuset_t *mask) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, cpuset_getaffinity, level, which, id, cpusetsize, mask);
+  int res = REAL(cpuset_getaffinity)(level, which, id, cpusetsize, mask);
+  if (mask && !res) COMMON_INTERCEPTOR_WRITE_RANGE(ctx, mask, cpusetsize);
+  return res;
+}
+#define INIT_CPUSET_GETAFFINITY COMMON_INTERCEPT_FUNCTION(cpuset_getaffinity);
+#else
+#define INIT_CPUSET_GETAFFINITY
+#endif
+
 #include "sanitizer_common_interceptors_netbsd_compat.inc"
 
 namespace __sanitizer {
@@ -10476,6 +10489,7 @@
   INIT___XUNAME;
   INIT_HEXDUMP;
   INIT_ARGP_PARSE;
+  INIT_CPUSET_GETAFFINITY;
 
   INIT___PRINTF_CHK;
 }
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
@@ -594,6 +594,7 @@
 #define SANITIZER_INTERCEPT_PROCCTL SI_FREEBSD
 #define SANITIZER_INTERCEPT_HEXDUMP SI_FREEBSD
 #define SANITIZER_INTERCEPT_ARGP_PARSE SI_GLIBC
+#define SANITIZER_INTERCEPT_CPUSET_GETAFFINITY SI_FREEBSD
 
 // This macro gives a way for downstream users to override the above
 // interceptor macros irrespective of the platform they are on. They have
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.h
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.h
@@ -715,6 +715,13 @@
 
 extern unsigned struct_fstab_sz;
 extern unsigned struct_StringList_sz;
+
+struct __sanitizer_cpuset {
+  long __bits[(256 + (sizeof(long) * 8) - 1) / (sizeof(long) * 8)];
+};
+
+typedef struct __sanitizer_cpuset __sanitizer_cpuset_t;
+extern unsigned struct_cpuset_sz;
 }  // namespace __sanitizer
 
 #  define CHECK_TYPE_SIZE(TYPE) \
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.cpp
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_freebsd.cpp
@@ -17,6 +17,7 @@
 
 #include <sys/capsicum.h>
 #include <sys/consio.h>
+#include <sys/cpuset.h>
 #include <sys/filio.h>
 #include <sys/ipc.h>
 #include <sys/kbio.h>
@@ -103,6 +104,7 @@
   return internal_dlinfo(handle, RTLD_DI_LINKMAP, &p) == 0 ? p : nullptr;
 }
 
+unsigned struct_cpuset_sz = sizeof(cpuset_t);
 unsigned struct_cap_rights_sz = sizeof(cap_rights_t);
 unsigned struct_utsname_sz = sizeof(struct utsname);
 unsigned struct_stat_sz = sizeof(struct stat);
@@ -564,4 +566,5 @@
 CHECK_TYPE_SIZE(sem_t);
 
 COMPILER_CHECK(sizeof(__sanitizer_cap_rights_t) >= sizeof(cap_rights_t));
+COMPILER_CHECK(sizeof(__sanitizer_cpuset_t) >= sizeof(cpuset_t));
 #endif  // SANITIZER_FREEBSD