diff --git a/Utilities/cmlibuv/include/uv.h b/Utilities/cmlibuv/include/uv.h
index 8e45dae82e..654a45c30c 100644
--- a/Utilities/cmlibuv/include/uv.h
+++ b/Utilities/cmlibuv/include/uv.h
@@ -1228,7 +1228,7 @@ struct uv_cpu_times_s {
 };
 
 struct uv_cpu_info_s {
-  char* model;
+  const char* model;
   int speed;
   struct uv_cpu_times_s cpu_times;
 };
diff --git a/Utilities/cmlibuv/include/uv/version.h b/Utilities/cmlibuv/include/uv/version.h
index b70cd6f60d..70f071a478 100644
--- a/Utilities/cmlibuv/include/uv/version.h
+++ b/Utilities/cmlibuv/include/uv/version.h
@@ -32,7 +32,7 @@
 
 #define UV_VERSION_MAJOR 1
 #define UV_VERSION_MINOR 52
-#define UV_VERSION_PATCH 0
+#define UV_VERSION_PATCH 1
 #define UV_VERSION_IS_RELEASE 1
 #define UV_VERSION_SUFFIX ""
 
diff --git a/Utilities/cmlibuv/src/inet.c b/Utilities/cmlibuv/src/inet.c
index 8c890dd0e4..f7416b46e9 100644
--- a/Utilities/cmlibuv/src/inet.c
+++ b/Utilities/cmlibuv/src/inet.c
@@ -151,19 +151,19 @@ int uv_inet_pton(int af, const char* src, void* dst) {
   case AF_INET:
     return (inet_pton4(src, dst));
   case AF_INET6: {
-    int len;
-    char tmp[UV__INET6_ADDRSTRLEN], *s, *p;
-    s = (char*) src;
+    const char *p;
     p = strchr(src, '%');
     if (p != NULL) {
-      s = tmp;
+      int len;
+      char s[UV__INET6_ADDRSTRLEN];
       len = p - src;
       if (len > UV__INET6_ADDRSTRLEN-1)
         return UV_EINVAL;
       memcpy(s, src, len);
       s[len] = '\0';
-    }
-    return inet_pton6(s, dst);
+      return inet_pton6(s, dst);
+    } else
+      return inet_pton6(src, dst);
   }
   default:
     return UV_EAFNOSUPPORT;
diff --git a/Utilities/cmlibuv/src/unix/aix.c b/Utilities/cmlibuv/src/unix/aix.c
index 30a2a894f2..4c0f4adb4c 100644
--- a/Utilities/cmlibuv/src/unix/aix.c
+++ b/Utilities/cmlibuv/src/unix/aix.c
@@ -380,7 +380,7 @@ uint64_t uv_get_total_memory(void) {
 
 
 uint64_t uv_get_constrained_memory(void) {
-  return 0;  /* Memory constraints are unknown. */
+  return uv__get_rlimit_max_memory();
 }
 
 
diff --git a/Utilities/cmlibuv/src/unix/core.c b/Utilities/cmlibuv/src/unix/core.c
index 0f997a2da9..08fdae0e46 100644
--- a/Utilities/cmlibuv/src/unix/core.c
+++ b/Utilities/cmlibuv/src/unix/core.c
@@ -2192,3 +2192,27 @@ int uv__sock_reuseport(int fd) {
 
   return 0;
 }
+
+/* Check if rlimit has any expressed restrictions on usable memory. */
+uint64_t uv__get_rlimit_max_memory(void) {
+  struct rlimit rl;
+  uint64_t result = 0;
+  uint64_t rlimit_value;
+
+#if defined(RLIMIT_AS)
+  if (getrlimit(RLIMIT_AS, &rl) == 0 && rl.rlim_cur != RLIM_INFINITY) {
+    rlimit_value = rl.rlim_cur;
+    result = rlimit_value;
+  }
+#endif
+
+#if defined(RLIMIT_DATA)
+  if (getrlimit(RLIMIT_DATA, &rl) == 0 && rl.rlim_cur != RLIM_INFINITY) {
+    rlimit_value = rl.rlim_cur;
+    if (result == 0 || rlimit_value < result)
+      result = rlimit_value;
+  }
+#endif
+
+  return result;
+}
diff --git a/Utilities/cmlibuv/src/unix/cygwin.c b/Utilities/cmlibuv/src/unix/cygwin.c
index 4913108223..29861ce8be 100644
--- a/Utilities/cmlibuv/src/unix/cygwin.c
+++ b/Utilities/cmlibuv/src/unix/cygwin.c
@@ -85,7 +85,7 @@ int uv_cpu_info(uv_cpu_info_t** cpu_infos, int* count) {
 }
 
 uint64_t uv_get_constrained_memory(void) {
-  return 0;  /* Memory constraints are unknown. */
+  return uv__get_rlimit_max_memory();
 }
 
 uint64_t uv_get_available_memory(void) {
diff --git a/Utilities/cmlibuv/src/unix/darwin.c b/Utilities/cmlibuv/src/unix/darwin.c
index a4e8129c39..e0d06bfebb 100644
--- a/Utilities/cmlibuv/src/unix/darwin.c
+++ b/Utilities/cmlibuv/src/unix/darwin.c
@@ -133,7 +133,7 @@ uint64_t uv_get_total_memory(void) {
 
 
 uint64_t uv_get_constrained_memory(void) {
-  return 0;  /* Memory constraints are unknown. */
+  return uv__get_rlimit_max_memory();
 }
 
 
diff --git a/Utilities/cmlibuv/src/unix/freebsd.c b/Utilities/cmlibuv/src/unix/freebsd.c
index a6de29c558..d7ac94b0c2 100644
--- a/Utilities/cmlibuv/src/unix/freebsd.c
+++ b/Utilities/cmlibuv/src/unix/freebsd.c
@@ -117,7 +117,7 @@ uint64_t uv_get_total_memory(void) {
 
 
 uint64_t uv_get_constrained_memory(void) {
-  return 0;  /* Memory constraints are unknown. */
+  return uv__get_rlimit_max_memory();
 }
 
 
diff --git a/Utilities/cmlibuv/src/unix/fs.c b/Utilities/cmlibuv/src/unix/fs.c
index dea3a55c9f..4900869580 100644
--- a/Utilities/cmlibuv/src/unix/fs.c
+++ b/Utilities/cmlibuv/src/unix/fs.c
@@ -487,27 +487,28 @@ static ssize_t uv__preadv_or_pwritev(int fd,
                                      off_t off,
                                      _Atomic uintptr_t* cache,
                                      int is_pread) {
-  ssize_t (*f)(int, const struct iovec*, uv__iovcnt, off_t);
-  void* p;
+  union {
+    ssize_t (*f)(int, const struct iovec*, uv__iovcnt, off_t);
+    void* p;
+  } u;
 
-  p = (void*) atomic_load_explicit(cache, memory_order_relaxed);
-  if (p == NULL) {
+  u.p = (void*) atomic_load_explicit(cache, memory_order_relaxed);
+  if (u.p == NULL) {
 #ifdef RTLD_DEFAULT
     /* Try _LARGEFILE_SOURCE version of preadv/pwritev first,
      * then fall back to the plain version, for libcs like musl.
      */
-    p = dlsym(RTLD_DEFAULT, is_pread ? "preadv64" : "pwritev64");
-    if (p == NULL)
-      p = dlsym(RTLD_DEFAULT, is_pread ? "preadv" : "pwritev");
+    u.p = dlsym(RTLD_DEFAULT, is_pread ? "preadv64" : "pwritev64");
+    if (u.p == NULL)
+      u.p = dlsym(RTLD_DEFAULT, is_pread ? "preadv" : "pwritev");
     dlerror();  /* Clear errors. */
 #endif  /* RTLD_DEFAULT */
-    if (p == NULL)
-      p = is_pread ? uv__preadv_emul : uv__pwritev_emul;
-    atomic_store_explicit(cache, (uintptr_t) p, memory_order_relaxed);
+    if (u.p == NULL)
+      u.f = is_pread ? uv__preadv_emul : uv__pwritev_emul;
+    atomic_store_explicit(cache, (uintptr_t) u.p, memory_order_relaxed);
   }
 
-  f = p;
-  return f(fd, bufs, nbufs, off);
+  return u.f(fd, bufs, nbufs, off);
 }
 
 
diff --git a/Utilities/cmlibuv/src/unix/getaddrinfo.c b/Utilities/cmlibuv/src/unix/getaddrinfo.c
index 6c44012726..5d90c7a59b 100644
--- a/Utilities/cmlibuv/src/unix/getaddrinfo.c
+++ b/Utilities/cmlibuv/src/unix/getaddrinfo.c
@@ -107,7 +107,9 @@ static void uv__getaddrinfo_done(struct uv__work* w, int status) {
   uv_getaddrinfo_t* req;
 
   req = container_of(w, uv_getaddrinfo_t, work_req);
-  uv__req_unregister(req->loop);
+
+  if (req->loop != NULL)
+    uv__req_unregister(req->loop);
 
   /* See initialization in uv_getaddrinfo(). */
   if (req->hints)
@@ -149,6 +151,8 @@ int uv_getaddrinfo(uv_loop_t* loop,
 
   if (req == NULL || (hostname == NULL && service == NULL))
     return UV_EINVAL;
+  if (loop == NULL && cb != NULL)
+    return UV_EINVAL;
 
   /* FIXME(bnoordhuis) IDNA does not seem to work z/OS,
    * probably because it uses EBCDIC rather than ASCII.
@@ -175,7 +179,10 @@ int uv_getaddrinfo(uv_loop_t* loop,
   if (buf == NULL)
     return UV_ENOMEM;
 
-  uv__req_init(loop, req, UV_GETADDRINFO);
+  UV_REQ_INIT(req, UV_GETADDRINFO);
+  if (loop != NULL)
+    uv__req_register(loop);
+
   req->loop = loop;
   req->cb = cb;
   req->addrinfo = NULL;
diff --git a/Utilities/cmlibuv/src/unix/haiku.c b/Utilities/cmlibuv/src/unix/haiku.c
index 0d3645f014..22c165916a 100644
--- a/Utilities/cmlibuv/src/unix/haiku.c
+++ b/Utilities/cmlibuv/src/unix/haiku.c
@@ -80,7 +80,7 @@ uint64_t uv_get_total_memory(void) {
 
 
 uint64_t uv_get_constrained_memory(void) {
-  return 0;  /* Memory constraints are unknown. */
+  return uv__get_rlimit_max_memory();
 }
 
 
diff --git a/Utilities/cmlibuv/src/unix/hurd.c b/Utilities/cmlibuv/src/unix/hurd.c
index 63c878123f..99f4f2ae48 100644
--- a/Utilities/cmlibuv/src/unix/hurd.c
+++ b/Utilities/cmlibuv/src/unix/hurd.c
@@ -163,7 +163,7 @@ int uv_cpu_info(uv_cpu_info_t** cpu_infos, int* count) {
 }
 
 uint64_t uv_get_constrained_memory(void) {
-  return 0;  /* Memory constraints are unknown. */
+  return uv__get_rlimit_max_memory();
 }
 
 
diff --git a/Utilities/cmlibuv/src/unix/ibmi.c b/Utilities/cmlibuv/src/unix/ibmi.c
index d5adaad137..2ede46b7f0 100644
--- a/Utilities/cmlibuv/src/unix/ibmi.c
+++ b/Utilities/cmlibuv/src/unix/ibmi.c
@@ -245,7 +245,7 @@ uint64_t uv_get_total_memory(void) {
 
 
 uint64_t uv_get_constrained_memory(void) {
-  return 0;  /* Memory constraints are unknown. */
+  return uv__get_rlimit_max_memory();
 }
 
 
diff --git a/Utilities/cmlibuv/src/unix/internal.h b/Utilities/cmlibuv/src/unix/internal.h
index 55af6d4d9d..1abbff0258 100644
--- a/Utilities/cmlibuv/src/unix/internal.h
+++ b/Utilities/cmlibuv/src/unix/internal.h
@@ -391,6 +391,7 @@ int uv__signal_loop_fork(uv_loop_t* loop);
 
 /* platform specific */
 uint64_t uv__hrtime(uv_clocktype_t type);
+uint64_t uv__get_rlimit_max_memory(void);
 int uv__kqueue_init(uv_loop_t* loop);
 int uv__platform_loop_init(uv_loop_t* loop);
 void uv__platform_loop_delete(uv_loop_t* loop);
@@ -481,12 +482,12 @@ UV_UNUSED(static void uv__update_time(uv_loop_t* loop)) {
   loop->time = uv__hrtime(UV_CLOCK_FAST) / 1000000;
 }
 
-UV_UNUSED(static char* uv__basename_r(const char* path)) {
-  char* s;
+UV_UNUSED(static const char* uv__basename_r(const char* path)) {
+  const char* s;
 
   s = strrchr(path, '/');
   if (s == NULL)
-    return (char*) path;
+    return path;
 
   return s + 1;
 }
diff --git a/Utilities/cmlibuv/src/unix/linux.c b/Utilities/cmlibuv/src/unix/linux.c
index 0ba2e987a3..6d1eb91a70 100644
--- a/Utilities/cmlibuv/src/unix/linux.c
+++ b/Utilities/cmlibuv/src/unix/linux.c
@@ -1742,7 +1742,7 @@ int uv_cpu_info(uv_cpu_info_t** ci, int* count) {
     unsigned model;
   };
   FILE* fp;
-  char* p;
+  const char* p;
   int found;
   int n;
   unsigned i;
@@ -2204,11 +2204,20 @@ static uint64_t uv__get_cgroup_constrained_memory(char buf[static 1024]) {
 
 uint64_t uv_get_constrained_memory(void) {
   char buf[1024];
+  uint64_t cgroup_limit;
+  uint64_t rlimit_limit;
 
-  if (uv__slurp("/proc/self/cgroup", buf, sizeof(buf)))
-    return 0;
+  cgroup_limit = 0;
+  if (uv__slurp("/proc/self/cgroup", buf, sizeof(buf)) == 0)
+    cgroup_limit = uv__get_cgroup_constrained_memory(buf);
+  rlimit_limit = uv__get_rlimit_max_memory();
 
-  return uv__get_cgroup_constrained_memory(buf);
+  /* Return the minimum of cgroup and rlimit constraints. */
+  if (cgroup_limit == 0)
+    return rlimit_limit;
+  if (rlimit_limit == 0)
+    return cgroup_limit;
+  return cgroup_limit < rlimit_limit ? cgroup_limit : rlimit_limit;
 }
 
 
@@ -2365,10 +2374,10 @@ next:
   return 0;
 }
 
-static char* uv__cgroup1_find_cpu_controller(const char* cgroup,
+static const char* uv__cgroup1_find_cpu_controller(const char* cgroup,
                                              int* cgroup_size) {
   /* Seek to the cpu controller line. */
-  char* cgroup_cpu = strstr(cgroup, ":cpu,");
+  const char* cgroup_cpu = strstr(cgroup, ":cpu,");
 
   if (cgroup_cpu != NULL) {
     /* Skip the controller prefix to the start of the cgroup path. */
@@ -2385,7 +2394,7 @@ static int uv__get_cgroupv1_constrained_cpu(const char* cgroup,
   char path[256];
   char buf[1024];
   int cgroup_size;
-  char* cgroup_cpu;
+  const char* cgroup_cpu;
   long long period_length;
   long long quota_per_period;
 
diff --git a/Utilities/cmlibuv/src/unix/netbsd.c b/Utilities/cmlibuv/src/unix/netbsd.c
index fa21e98e41..37d962c4b1 100644
--- a/Utilities/cmlibuv/src/unix/netbsd.c
+++ b/Utilities/cmlibuv/src/unix/netbsd.c
@@ -127,7 +127,7 @@ uint64_t uv_get_total_memory(void) {
 
 
 uint64_t uv_get_constrained_memory(void) {
-  return 0;  /* Memory constraints are unknown. */
+  return uv__get_rlimit_max_memory();
 }
 
 
diff --git a/Utilities/cmlibuv/src/unix/openbsd.c b/Utilities/cmlibuv/src/unix/openbsd.c
index a6d58b948e..bc66316955 100644
--- a/Utilities/cmlibuv/src/unix/openbsd.c
+++ b/Utilities/cmlibuv/src/unix/openbsd.c
@@ -94,7 +94,7 @@ uint64_t uv_get_total_memory(void) {
 
 
 uint64_t uv_get_constrained_memory(void) {
-  return 0;  /* Memory constraints are unknown. */
+  return uv__get_rlimit_max_memory();
 }
 
 
diff --git a/Utilities/cmlibuv/src/unix/os390.c b/Utilities/cmlibuv/src/unix/os390.c
index c049884c4b..6ba2f9158b 100644
--- a/Utilities/cmlibuv/src/unix/os390.c
+++ b/Utilities/cmlibuv/src/unix/os390.c
@@ -188,12 +188,23 @@ uint64_t uv_get_total_memory(void) {
 
 uint64_t uv_get_constrained_memory(void) {
   struct rlimit rl;
+  uint64_t memlimit;
+  uint64_t rlimit_limit;
 
   /* RLIMIT_MEMLIMIT return value is in megabytes rather than bytes. */
-  if (getrlimit(RLIMIT_MEMLIMIT, &rl) == 0)
-    return rl.rlim_cur * 1024 * 1024;
+  memlimit = 0;
+  if (getrlimit(RLIMIT_MEMLIMIT, &rl) == 0 && rl.rlim_cur != RLIM_INFINITY)
+    memlimit = rl.rlim_cur * 1024 * 1024;
 
-  return 0; /* There is no memory limit set. */
+  /* Also check RLIMIT_AS and RLIMIT_DATA. */
+  rlimit_limit = uv__get_rlimit_max_memory();
+
+  /* Return the minimum of RLIMIT_MEMLIMIT and other rlimits. */
+  if (memlimit == 0)
+    return rlimit_limit;
+  if (rlimit_limit == 0)
+    return memlimit;
+  return memlimit < rlimit_limit ? memlimit : rlimit_limit;
 }
 
 
diff --git a/Utilities/cmlibuv/src/unix/qnx.c b/Utilities/cmlibuv/src/unix/qnx.c
index d873165fee..c1030caf74 100644
--- a/Utilities/cmlibuv/src/unix/qnx.c
+++ b/Utilities/cmlibuv/src/unix/qnx.c
@@ -118,7 +118,7 @@ uint64_t uv_get_total_memory(void) {
 
 
 uint64_t uv_get_constrained_memory(void) {
-  return 0;
+  return uv__get_rlimit_max_memory();
 }
 
 
diff --git a/Utilities/cmlibuv/src/unix/sunos.c b/Utilities/cmlibuv/src/unix/sunos.c
index 0793122976..5abe077d57 100644
--- a/Utilities/cmlibuv/src/unix/sunos.c
+++ b/Utilities/cmlibuv/src/unix/sunos.c
@@ -397,7 +397,7 @@ uint64_t uv_get_total_memory(void) {
 
 
 uint64_t uv_get_constrained_memory(void) {
-  return 0;  /* Memory constraints are unknown. */
+  return uv__get_rlimit_max_memory();
 }
 
 
diff --git a/Utilities/cmlibuv/src/unix/udp.c b/Utilities/cmlibuv/src/unix/udp.c
index 20dc85fc3f..d473469f0f 100644
--- a/Utilities/cmlibuv/src/unix/udp.c
+++ b/Utilities/cmlibuv/src/unix/udp.c
@@ -183,7 +183,11 @@ void uv__udp_io(uv_loop_t* loop, uv__io_t* w, unsigned int revents) {
 
   /* Just Linux support for now. */
 #if defined(__linux__)
-  if (revents & POLLERR)
+  /* Guard against the case where the POLLIN callback above (e.g. via
+   * uv_udp_recv_stop + uv_close) already cleared recv_cb in the same
+   * revents iteration.  uv__udp_recvmsg asserts recv_cb != NULL, so
+   * calling it with a NULL recv_cb would be wrong regardless of POLLERR. */
+  if ((revents & POLLERR) && uv__is_active(handle))
     uv__udp_recvmsg(handle, MSG_ERRQUEUE);
 #endif
 
diff --git a/Utilities/cmlibuv/src/uv-common.c b/Utilities/cmlibuv/src/uv-common.c
index 050bc9dd9b..c0d850f3b3 100644
--- a/Utilities/cmlibuv/src/uv-common.c
+++ b/Utilities/cmlibuv/src/uv-common.c
@@ -959,7 +959,7 @@ void uv_free_cpu_info(uv_cpu_info_t* cpu_infos, int count) {
   int i;
 
   for (i = 0; i < count; i++)
-    uv__free(cpu_infos[i].model);
+    uv__free((char*) cpu_infos[i].model);
 
   uv__free(cpu_infos);
 #endif  /* __linux__ */
diff --git a/Utilities/cmlibuv/src/win/getaddrinfo.c b/Utilities/cmlibuv/src/win/getaddrinfo.c
index 4b8ee75a06..9404ccf70f 100644
--- a/Utilities/cmlibuv/src/win/getaddrinfo.c
+++ b/Utilities/cmlibuv/src/win/getaddrinfo.c
@@ -208,7 +208,8 @@ static void uv__getaddrinfo_done(struct uv__work* w, int status) {
   }
 
 complete:
-  uv__req_unregister(req->loop);
+  if (req->loop != NULL)
+    uv__req_unregister(req->loop);
 
   /* finally do callback with converted result */
   if (req->getaddrinfo_cb)
@@ -239,7 +240,7 @@ void uv_freeaddrinfo(struct addrinfo* ai) {
  */
 int uv_getaddrinfo(uv_loop_t* loop,
                    uv_getaddrinfo_t* req,
-                   uv_getaddrinfo_cb getaddrinfo_cb,
+                   uv_getaddrinfo_cb cb,
                    const char* node,
                    const char* service,
                    const struct addrinfo* hints) {
@@ -252,12 +253,15 @@ int uv_getaddrinfo(uv_loop_t* loop,
   size_t hintoff = 0;
   ssize_t rc;
 
-  if (req == NULL || (node == NULL && service == NULL)) {
+  if (req == NULL || (node == NULL && service == NULL))
     return UV_EINVAL;
-  }
+  if (loop == NULL && cb != NULL)
+    return UV_EINVAL;
+
+  uv__once_init();
 
   UV_REQ_INIT(req, UV_GETADDRINFO);
-  req->getaddrinfo_cb = getaddrinfo_cb;
+  req->getaddrinfo_cb = cb;
   req->addrinfo = NULL;
   req->loop = loop;
   req->retcode = 0;
@@ -330,9 +334,10 @@ int uv_getaddrinfo(uv_loop_t* loop,
     req->addrinfow = NULL;
   }
 
-  uv__req_register(loop);
+  if (loop != NULL)
+    uv__req_register(loop);
 
-  if (getaddrinfo_cb) {
+  if (cb) {
     uv__work_submit(loop,
                     &req->work_req,
                     UV__WORK_SLOW_IO,
diff --git a/Utilities/cmlibuv/src/win/util.c b/Utilities/cmlibuv/src/win/util.c
index fec07b269f..436bf30557 100644
--- a/Utilities/cmlibuv/src/win/util.c
+++ b/Utilities/cmlibuv/src/win/util.c
@@ -627,7 +627,7 @@ int uv_cpu_info(uv_cpu_info_t** cpu_infos_ptr, int* cpu_count_ptr) {
 
     uv__convert_utf16_to_utf8(cpu_brand,
                               cpu_brand_size / sizeof(WCHAR),
-                              &(cpu_info->model));
+                              (char**) &(cpu_info->model));
   }
 
   uv__free(sppi);
@@ -639,12 +639,8 @@ int uv_cpu_info(uv_cpu_info_t** cpu_infos_ptr, int* cpu_count_ptr) {
 
  error:
   if (cpu_infos != NULL) {
-    /* This is safe because the cpu_infos array is zeroed on allocation. */
-    for (i = 0; i < cpu_count; i++)
-      uv__free(cpu_infos[i].model);
+    uv_free_cpu_info(cpu_infos, cpu_count);
   }
-
-  uv__free(cpu_infos);
   uv__free(sppi);
 
   return uv_translate_sys_error(err);