diff --git a/include/uv.h b/include/uv.h
index 77503bde..17940e3d 100644
--- a/include/uv.h
+++ b/include/uv.h
@@ -797,6 +797,16 @@ UV_EXTERN void uv_pipe_connect(uv_connect_t* req,
                                uv_pipe_t* handle,
                                const char* name,
                                uv_connect_cb cb);
+#ifdef CONFIG_NET_RPMSG
+UV_EXTERN int uv_pipe_rpmsg_bind(uv_pipe_t* handle,
+                                 const char* name,
+                                 const char* cpu_name);
+UV_EXTERN void uv_pipe_rpmsg_connect(uv_connect_t* req,
+                                     uv_pipe_t* handle,
+                                     const char* name,
+                                     const char* cpu_name,
+                                     uv_connect_cb cb);
+#endif
 UV_EXTERN int uv_pipe_getsockname(const uv_pipe_t* handle,
                                   char* buffer,
                                   size_t* size);
diff --git a/include/uv/unix.h b/include/uv/unix.h
index e3cf7bdd..bf8dc32c 100644
--- a/include/uv/unix.h
+++ b/include/uv/unix.h
@@ -71,6 +71,8 @@
 # include "uv/posix.h"
 #elif defined(__QNX__)
 # include "uv/posix.h"
+#elif defined(__NuttX__)
+# include "uv/posix.h"
 #endif
 
 #ifndef NI_MAXHOST
diff --git a/src/fs-poll.c b/src/fs-poll.c
index 89864e23..ceb047cb 100644
--- a/src/fs-poll.c
+++ b/src/fs-poll.c
@@ -53,7 +53,7 @@ static void poll_cb(uv_fs_t* req);
 static void timer_cb(uv_timer_t* timer);
 static void timer_close_cb(uv_handle_t* handle);
 
-static uv_stat_t zero_statbuf;
+static const uv_stat_t zero_statbuf;
 
 
 int uv_fs_poll_init(uv_loop_t* loop, uv_fs_poll_t* handle) {
diff --git a/src/random.c b/src/random.c
index e75f77de..feef5a44 100644
--- a/src/random.c
+++ b/src/random.c
@@ -31,7 +31,7 @@
 static int uv__random(void* buf, size_t buflen) {
   int rc;
 
-#if defined(__PASE__)
+#if defined(__PASE__) || defined(__NuttX__)
   rc = uv__random_readpath("/dev/urandom", buf, buflen);
 #elif defined(_AIX) || defined(__QNX__)
   rc = uv__random_readpath("/dev/random", buf, buflen);
diff --git a/src/threadpool.c b/src/threadpool.c
index 869ae95f..8fabeba5 100644
--- a/src/threadpool.c
+++ b/src/threadpool.c
@@ -20,6 +20,7 @@
  */
 
 #include "uv-common.h"
+#include "uv-global.h"
 
 #if !defined(_WIN32)
 # include "unix/internal.h"
@@ -27,20 +28,11 @@
 
 #include <stdlib.h>
 
-#define MAX_THREADPOOL_SIZE 1024
+#ifndef DEF_THREADPOOL_SIZE
+# define DEF_THREADPOOL_SIZE 4
+#endif
 
-static uv_once_t once = UV_ONCE_INIT;
-static uv_cond_t cond;
-static uv_mutex_t mutex;
-static unsigned int idle_threads;
-static unsigned int slow_io_work_running;
-static unsigned int nthreads;
-static uv_thread_t* threads;
-static uv_thread_t default_threads[4];
-static QUEUE exit_message;
-static QUEUE wq;
-static QUEUE run_slow_work_message;
-static QUEUE slow_io_pending_wq;
+#define MAX_THREADPOOL_SIZE 1024
 
 static unsigned int slow_work_thread_threshold(void) {
   return (nthreads + 1) / 2;
@@ -68,16 +60,16 @@ static void worker(void* arg) {
 
     /* Keep waiting while either no work is present or only slow I/O
        and we're at the threshold for that. */
-    while (QUEUE_EMPTY(&wq) ||
-           (QUEUE_HEAD(&wq) == &run_slow_work_message &&
-            QUEUE_NEXT(&run_slow_work_message) == &wq &&
+    while (QUEUE_EMPTY(&lwq) ||
+           (QUEUE_HEAD(&lwq) == &run_slow_work_message &&
+            QUEUE_NEXT(&run_slow_work_message) == &lwq &&
             slow_io_work_running >= slow_work_thread_threshold())) {
       idle_threads += 1;
       uv_cond_wait(&cond, &mutex);
       idle_threads -= 1;
     }
 
-    q = QUEUE_HEAD(&wq);
+    q = QUEUE_HEAD(&lwq);
     if (q == &exit_message) {
       uv_cond_signal(&cond);
       uv_mutex_unlock(&mutex);
@@ -92,7 +84,7 @@ static void worker(void* arg) {
       /* If we're at the slow I/O threshold, re-schedule until after all
          other work in the queue is done. */
       if (slow_io_work_running >= slow_work_thread_threshold()) {
-        QUEUE_INSERT_TAIL(&wq, q);
+        QUEUE_INSERT_TAIL(&lwq, q);
         continue;
       }
 
@@ -110,7 +102,7 @@ static void worker(void* arg) {
 
       /* If there is more slow I/O work, schedule it to be run as well. */
       if (!QUEUE_EMPTY(&slow_io_pending_wq)) {
-        QUEUE_INSERT_TAIL(&wq, &run_slow_work_message);
+        QUEUE_INSERT_TAIL(&lwq, &run_slow_work_message);
         if (idle_threads > 0)
           uv_cond_signal(&cond);
       }
@@ -153,13 +145,21 @@ static void post(QUEUE* q, enum uv__work_kind kind) {
     q = &run_slow_work_message;
   }
 
-  QUEUE_INSERT_TAIL(&wq, q);
+  QUEUE_INSERT_TAIL(&lwq, q);
   if (idle_threads > 0)
     uv_cond_signal(&cond);
   uv_mutex_unlock(&mutex);
 }
 
 
+#ifndef _WIN32
+static void reset_once(void) {
+  uv_once_t child_once = UV_ONCE_INIT;
+  memcpy(&once, &child_once, sizeof(child_once));
+}
+#endif
+
+
 void uv__threadpool_cleanup(void) {
   unsigned int i;
 
@@ -180,6 +180,11 @@ void uv__threadpool_cleanup(void) {
 
   threads = NULL;
   nthreads = 0;
+
+#ifndef _WIN32
+  reset_once();
+#endif
+
 }
 
 
@@ -212,7 +217,7 @@ static void init_threads(void) {
   if (uv_mutex_init(&mutex))
     abort();
 
-  QUEUE_INIT(&wq);
+  QUEUE_INIT(&lwq);
   QUEUE_INIT(&slow_io_pending_wq);
   QUEUE_INIT(&run_slow_work_message);
 
@@ -230,14 +235,6 @@ static void init_threads(void) {
 }
 
 
-#ifndef _WIN32
-static void reset_once(void) {
-  uv_once_t child_once = UV_ONCE_INIT;
-  memcpy(&once, &child_once, sizeof(child_once));
-}
-#endif
-
-
 static void init_once(void) {
 #ifndef _WIN32
   /* Re-initialize the threadpool after fork.
diff --git a/src/unix/core.c b/src/unix/core.c
index 71e9c525..6859fe71 100644
--- a/src/unix/core.c
+++ b/src/unix/core.c
@@ -58,8 +58,6 @@
 # include <crt_externs.h>
 # include <mach-o/dyld.h> /* _NSGetExecutablePath */
 # define environ (*_NSGetEnviron())
-#else /* defined(__APPLE__) && !TARGET_OS_IPHONE */
-extern char** environ;
 #endif /* !(defined(__APPLE__) && !TARGET_OS_IPHONE) */
 
 
@@ -987,7 +985,7 @@ int uv_getrusage(uv_rusage_t* rusage) {
   rusage->ru_stime.tv_sec = usage.ru_stime.tv_sec;
   rusage->ru_stime.tv_usec = usage.ru_stime.tv_usec;
 
-#if !defined(__MVS__) && !defined(__HAIKU__)
+#if !defined(__MVS__) && !defined(__HAIKU__) && !defined(__NuttX__)
   rusage->ru_maxrss = usage.ru_maxrss;
   rusage->ru_ixrss = usage.ru_ixrss;
   rusage->ru_idrss = usage.ru_idrss;
diff --git a/src/unix/loop.c b/src/unix/loop.c
index a88e71c3..dad463b3 100644
--- a/src/unix/loop.c
+++ b/src/unix/loop.c
@@ -220,8 +220,10 @@ int uv__loop_configure(uv_loop_t* loop, uv_loop_option option, va_list ap) {
   if (option != UV_LOOP_BLOCK_SIGNAL)
     return UV_ENOSYS;
 
+#ifdef SIGPROF
   if (va_arg(ap, int) != SIGPROF)
     return UV_EINVAL;
+#endif
 
   loop->flags |= UV_LOOP_BLOCK_SIGPROF;
   return 0;
diff --git a/src/unix/nuttx.c b/src/unix/nuttx.c
new file mode 100644
index 00000000..728b57f6
--- /dev/null
+++ b/src/unix/nuttx.c
@@ -0,0 +1,284 @@
+/* Copyright Xiaomi, Inc. and other Node contributors. All rights reserved.
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+/* We lean on the fact that POLL{IN,OUT,ERR,HUP} correspond with their
+ * EPOLL* counterparts.  We use the POLL* variants in this file because that
+ * is what libuv uses elsewhere.
+ */
+
+#include "internal.h"
+#include "uv.h"
+#include "uv-global.h"
+
+#include <ifaddrs.h>
+#include <malloc.h>
+#include <net/if.h>
+#include <pthread.h>
+#include <sys/sysinfo.h>
+#include <unistd.h>
+
+int uv_exepath(char* buffer, size_t* size) {
+  return UV_ENOTSUP;
+}
+
+char** uv_setup_args(int argc, char** argv) {
+  return argv;
+}
+
+void uv__process_title_cleanup(void) {
+}
+
+int uv_set_process_title(const char* title) {
+  return UV__ERR(pthread_setname_np(pthread_self(), title));
+}
+
+int uv_get_process_title(char* buffer, size_t size) {
+  return UV__ERR(pthread_getname_np(pthread_self(), buffer, size));
+}
+
+uint64_t uv_get_constrained_memory(void) {
+  return 0;  /* Memory constraints are unknown. */
+}
+
+int uv_resident_set_memory(size_t* rss) {
+  struct sysinfo info;
+  int ret;
+
+  ret = sysinfo(&info);
+  if (ret >= 0)
+    {
+      *rss = (info.totalram - info.freeram) * info.mem_unit;
+    }
+  else
+    {
+      ret = UV__ERR(errno);
+    }
+
+  return ret;
+}
+
+int uv_uptime(double* uptime) {
+  struct sysinfo info;
+  int ret;
+
+
+  ret = sysinfo(&info);
+  if (ret >= 0)
+    {
+      *uptime = info.uptime;
+    }
+  else
+    {
+      ret = UV__ERR(errno);
+    }
+
+  return ret;
+}
+
+int uv_cpu_info(uv_cpu_info_t** cpu_infos, int* count) {
+  *count = sysconf(_SC_NPROCESSORS_ONLN);
+  *cpu_infos = uv__calloc(*count, sizeof(uv_cpu_info_t));
+  if (!*cpu_infos) {
+    return UV_ENOMEM;
+  }
+
+  return 0;
+}
+
+#ifndef CONFIG_NETDEV_IFINDEX
+unsigned int if_nametoindex(const char *ifname) {
+  return 0;
+}
+
+int uv_interface_addresses(uv_interface_address_t** addresses, int* count) {
+  return UV_ENOSYS;
+}
+
+void uv_free_interface_addresses(uv_interface_address_t* addresses, int count) {
+}
+#else
+static int uv__ifaddr_exclude(struct ifaddrs *ent) {
+  if (!((ent->ifa_flags & IFF_UP) && (ent->ifa_flags & IFF_RUNNING)))
+    return 1;
+  if (ent->ifa_addr == NULL)
+    return 1;
+  return 0;
+}
+
+int uv_interface_addresses(uv_interface_address_t** addresses, int* count) {
+  struct ifaddrs* addrs;
+  struct ifaddrs* ent;
+  uv_interface_address_t* address;
+
+  *count = 0;
+  *addresses = NULL;
+
+  if (getifaddrs(&addrs) != 0)
+    return UV__ERR(errno);
+
+  /* Count the number of interfaces */
+  for (ent = addrs; ent != NULL; ent = ent->ifa_next) {
+    if (uv__ifaddr_exclude(ent))
+      continue;
+    (*count)++;
+  }
+
+  if (*count == 0) {
+    freeifaddrs(addrs);
+    return 0;
+  }
+
+  /* Make sure the memory is initiallized to zero using calloc() */
+  *addresses = uv__calloc(*count, sizeof(**addresses));
+  if (*addresses == NULL) {
+    freeifaddrs(addrs);
+    return UV_ENOMEM;
+  }
+
+  address = *addresses;
+  for (ent = addrs; ent != NULL; ent = ent->ifa_next) {
+    if (uv__ifaddr_exclude(ent))
+      continue;
+
+    address->name = uv__strdup(ent->ifa_name);
+
+    if (ent->ifa_addr->sa_family == AF_INET6) {
+      address->address.address6 = *((struct sockaddr_in6*) ent->ifa_addr);
+    } else {
+      address->address.address4 = *((struct sockaddr_in*) ent->ifa_addr);
+    }
+
+    if (ent->ifa_netmask) {
+      if (ent->ifa_netmask->sa_family == AF_INET6) {
+        address->netmask.netmask6 = *((struct sockaddr_in6*) ent->ifa_netmask);
+      } else {
+        address->netmask.netmask4 = *((struct sockaddr_in*) ent->ifa_netmask);
+      }
+    }
+
+    if (ent->ifa_data) {
+      struct sockaddr* addr = ent->ifa_data;
+      memcpy(address->phys_addr, addr->sa_data, sizeof(address->phys_addr));
+    }
+
+    address->is_internal = !strcmp(address->name, "lo");
+    address++;
+  }
+
+  freeifaddrs(addrs);
+  return 0;
+}
+
+void uv_free_interface_addresses(uv_interface_address_t* addresses, int count) {
+  int i;
+
+  for (i = 0; i < count; i++) {
+    uv__free(addresses[i].name);
+  }
+
+  uv__free(addresses);
+}
+#endif
+
+#ifndef CONFIG_NET_SOCKOPTS
+int getsockopt(int sockfd, int level, int option, void *value, socklen_t *value_len) {
+  return UV_ENOTSUP;
+}
+#endif
+
+#ifndef CONFIG_NET
+int getsockname(int sockfd, struct sockaddr *addr, socklen_t *addrlen) {
+  return UV_ENOTSUP;
+}
+
+ssize_t recvmsg(int sockfd, struct msghdr *msg, int flags) {
+  return UV_ENOTSUP;
+}
+
+ssize_t sendmsg(int sockfd, struct msghdr *msg, int flags) {
+  return UV_ENOTSUP;
+}
+
+int shutdown(int sockfd, int how) {
+  return UV_ENOTSUP;
+}
+#endif
+
+#ifndef CONFIG_NET_TCP
+void uv__tcp_close(uv_tcp_t* handle) {
+}
+
+int uv__tcp_nodelay(int fd, int on) {
+  return UV_ENOTSUP;
+}
+
+int uv__tcp_keepalive(int fd, int on, unsigned int delay) {
+  return UV_ENOTSUP;
+}
+#endif
+
+#ifndef CONFIG_NET_UDP
+void uv__udp_close(uv_udp_t* handle) {
+}
+
+void uv__udp_finish_close(uv_udp_t* handle) {
+}
+#endif
+
+#if CONFIG_TLS_TASK_NELEM == 0
+#  error "libuv depends on CONFIG_TLS_TASK_NELEM, please enable it by menuconfig"
+#endif
+
+#undef once
+#undef uv__signal_global_init_guard
+#undef uv__signal_lock_pipefd
+
+static void uv__global_free(void* global) {
+  if (global) {
+    uv_library_shutdown();
+    uv__free(global);
+  }
+}
+
+uv__global_t* uv__global_get(void) {
+  static int index = -1;
+  uv__global_t* global = NULL;
+
+  if (index < 0) {
+    index = task_tls_alloc(uv__global_free);
+  }
+
+  if (index >= 0) {
+    global = (uv__global_t*)task_tls_get_value(index);
+    if (global == NULL) {
+      global = (uv__global_t*)uv__calloc(1, sizeof(uv__global_t));
+      if (global) {
+          global->once = UV_ONCE_INIT;
+          global->uv__signal_global_init_guard = UV_ONCE_INIT;
+          global->uv__signal_lock_pipefd[0] = -1;
+          global->uv__signal_lock_pipefd[1] = -1;
+          task_tls_set_value(index, (uintptr_t)global);
+      }
+    }
+  }
+
+  ASSERT(global != NULL);
+  return global;
+}
diff --git a/src/unix/pipe.c b/src/unix/pipe.c
index 788e038e..9104cb92 100644
--- a/src/unix/pipe.c
+++ b/src/unix/pipe.c
@@ -28,7 +28,9 @@
 #include <sys/un.h>
 #include <unistd.h>
 #include <stdlib.h>
-
+#ifdef CONFIG_NET_RPMSG
+#include <netpacket/rpmsg.h>
+#endif // CONFIG_NET_RPMSG
 
 int uv_pipe_init(uv_loop_t* loop, uv_pipe_t* handle, int ipc) {
   uv__stream_init(loop, (uv_stream_t*)handle, UV_NAMED_PIPE);
@@ -90,6 +92,48 @@ err_socket:
   return err;
 }
 
+#ifdef CONFIG_NET_RPMSG
+int uv_pipe_rpmsg_bind(uv_pipe_t* handle,
+                       const char* name,
+                       const char* cpu_name) {
+  struct sockaddr_rpmsg saddr;
+  int sockfd;
+  int err;
+
+  /* Already bound? */
+  if (uv__stream_fd(handle) >= 0)
+    return UV_EINVAL;
+
+  err = uv__socket(AF_RPMSG, SOCK_STREAM, 0);
+  if (err < 0)
+    goto err_socket;
+  sockfd = err;
+
+  memset(&saddr, 0, sizeof saddr);
+  uv__strscpy(saddr.rp_name, name, sizeof(saddr.rp_name));
+  uv__strscpy(saddr.rp_cpu, cpu_name, sizeof(saddr.rp_cpu));
+  saddr.rp_family = AF_RPMSG;
+
+  if (bind(sockfd, (struct sockaddr*)&saddr, sizeof saddr)) {
+    err = UV__ERR(errno);
+    /* Convert ENOENT to EACCES for compatibility with Windows. */
+    if (err == UV_ENOENT)
+      err = UV_EACCES;
+
+    uv__close(sockfd);
+    goto err_socket;
+  }
+
+  /* Success. */
+  handle->flags |= UV_HANDLE_BOUND;
+  handle->pipe_fname = NULL;
+  handle->io_watcher.fd = sockfd;
+  return 0;
+
+err_socket:
+  return err;
+}
+#endif
 
 int uv_pipe_listen(uv_pipe_t* handle, int backlog, uv_connection_cb cb) {
   if (uv__stream_fd(handle) == -1)
@@ -169,32 +213,18 @@ int uv_pipe_open(uv_pipe_t* handle, uv_file fd) {
   return uv__stream_open((uv_stream_t*)handle, fd, flags);
 }
 
-
-void uv_pipe_connect(uv_connect_t* req,
-                    uv_pipe_t* handle,
-                    const char* name,
-                    uv_connect_cb cb) {
-  struct sockaddr_un saddr;
-  int new_sock;
+static inline int uv__connect(uv_connect_t* req,
+                               uv_pipe_t* handle,
+                               struct sockaddr* saddr,
+                               socklen_t addrlen,
+                               int new_sock,
+                               uv_connect_cb cb)
+{
   int err;
   int r;
 
-  new_sock = (uv__stream_fd(handle) == -1);
-
-  if (new_sock) {
-    err = uv__socket(AF_UNIX, SOCK_STREAM, 0);
-    if (err < 0)
-      goto out;
-    handle->io_watcher.fd = err;
-  }
-
-  memset(&saddr, 0, sizeof saddr);
-  uv__strscpy(saddr.sun_path, name, sizeof(saddr.sun_path));
-  saddr.sun_family = AF_UNIX;
-
   do {
-    r = connect(uv__stream_fd(handle),
-                (struct sockaddr*)&saddr, sizeof saddr);
+    r = connect(uv__stream_fd(handle), saddr, addrlen);
   }
   while (r == -1 && errno == EINTR);
 
@@ -222,6 +252,14 @@ void uv_pipe_connect(uv_connect_t* req,
     uv__io_start(handle->loop, &handle->io_watcher, POLLOUT);
 
 out:
+  return err;
+}
+
+static inline void uv__connect_handle_err(uv_connect_t* req,
+                                          uv_pipe_t* handle,
+                                          int err,
+                                          uv_connect_cb cb)
+{
   handle->delayed_error = err;
   handle->connect_req = req;
 
@@ -233,9 +271,66 @@ out:
   /* Force callback to run on next tick in case of error. */
   if (err)
     uv__io_feed(handle->loop, &handle->io_watcher);
+}
+
+void uv_pipe_connect(uv_connect_t* req,
+                    uv_pipe_t* handle,
+                    const char* name,
+                    uv_connect_cb cb) {
+  struct sockaddr_un saddr;
+  int new_sock;
+  int err;
+
+  new_sock = (uv__stream_fd(handle) == -1);
+
+  if (new_sock) {
+    err = uv__socket(AF_UNIX, SOCK_STREAM, 0);
+    if (err < 0)
+      goto out;
+    handle->io_watcher.fd = err;
+  }
+
+  memset(&saddr, 0, sizeof saddr);
+  uv__strscpy(saddr.sun_path, name, sizeof(saddr.sun_path));
+  saddr.sun_family = AF_UNIX;
+
+  err = uv__connect(req, handle, (struct sockaddr*)&saddr, sizeof saddr,
+                    new_sock, cb);
 
+out:
+    uv__connect_handle_err(req, handle, err, cb);
 }
 
+#ifdef CONFIG_NET_RPMSG
+void uv_pipe_rpmsg_connect(uv_connect_t* req,
+                           uv_pipe_t* handle,
+                           const char* name,
+                           const char* cpu_name,
+                           uv_connect_cb cb) {
+  struct sockaddr_rpmsg saddr;
+  int new_sock;
+  int err;
+
+  new_sock = (uv__stream_fd(handle) == -1);
+
+  if (new_sock) {
+    err = uv__socket(AF_RPMSG, SOCK_STREAM, 0);
+    if (err < 0)
+      goto out;
+    handle->io_watcher.fd = err;
+  }
+
+  memset(&saddr, 0, sizeof saddr);
+  uv__strscpy(saddr.rp_name, name, sizeof(saddr.rp_name));
+  uv__strscpy(saddr.rp_cpu, cpu_name, sizeof(saddr.rp_cpu));
+  saddr.rp_family = AF_RPMSG;
+  err = uv__connect(req, handle, (struct sockaddr*)&saddr, sizeof saddr,
+                    new_sock, cb);
+
+out:
+    uv__connect_handle_err(req, handle, err, cb);
+}
+#endif // CONFIG_NET_RPMSG
 
 static int uv__pipe_getsockpeername(const uv_pipe_t* handle,
                                     uv__peersockfunc func,
diff --git a/src/unix/posix-poll.c b/src/unix/posix-poll.c
index 0f4bf938..dd36028b 100644
--- a/src/unix/posix-poll.c
+++ b/src/unix/posix-poll.c
@@ -144,7 +144,7 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
   int have_signals;
   struct pollfd* pe;
   int fd;
-  int user_timeout;
+  int user_timeout = 0;
   int reset_timeout;
 
   if (loop->nfds == 0) {
@@ -170,11 +170,15 @@ void uv__io_poll(uv_loop_t* loop, int timeout) {
 
   /* Prepare a set of signals to block around poll(), if any.  */
   pset = NULL;
+#ifdef SIGPROF
   if (loop->flags & UV_LOOP_BLOCK_SIGPROF) {
     pset = &set;
     sigemptyset(pset);
     sigaddset(pset, SIGPROF);
   }
+#else
+  (void) set;
+#endif
 
   assert(timeout >= -1);
   time_base = loop->time;
diff --git a/src/unix/process.c b/src/unix/process.c
index f4aebb04..00409cbc 100644
--- a/src/unix/process.c
+++ b/src/unix/process.c
@@ -36,8 +36,6 @@
 #if defined(__APPLE__) && !TARGET_OS_IPHONE
 # include <crt_externs.h>
 # define environ (*_NSGetEnviron())
-#else
-extern char **environ;
 #endif
 
 #if defined(__linux__) || defined(__GLIBC__)
@@ -48,7 +46,7 @@ extern char **environ;
 # include "zos-base.h"
 #endif
 
-
+#if !(defined(__APPLE__) && (TARGET_OS_TV || TARGET_OS_WATCH)) && !defined(__NuttX__)
 static void uv__chld(uv_signal_t* handle, int signum) {
   uv_process_t* process;
   uv_loop_t* loop;
@@ -207,7 +205,6 @@ static void uv__write_errno(int error_fd) {
 }
 
 
-#if !(defined(__APPLE__) && (TARGET_OS_TV || TARGET_OS_WATCH))
 /* execvp is marked __WATCHOS_PROHIBITED __TVOS_PROHIBITED, so must be
  * avoided. Since this isn't called on those targets, the function
  * doesn't even need to be defined for them.
@@ -345,7 +342,7 @@ static void uv__process_child_init(const uv_process_options_t* options,
 int uv_spawn(uv_loop_t* loop,
              uv_process_t* process,
              const uv_process_options_t* options) {
-#if defined(__APPLE__) && (TARGET_OS_TV || TARGET_OS_WATCH)
+#if (defined(__APPLE__) && (TARGET_OS_TV || TARGET_OS_WATCH)) || defined(__NuttX__)
   /* fork is marked __WATCHOS_PROHIBITED __TVOS_PROHIBITED. */
   return UV_ENOSYS;
 #else
diff --git a/src/unix/signal.c b/src/unix/signal.c
index 1133c73a..1827832b 100644
--- a/src/unix/signal.c
+++ b/src/unix/signal.c
@@ -20,6 +20,7 @@
 
 #include "uv.h"
 #include "internal.h"
+#include "uv-global.h"
 
 #include <assert.h>
 #include <errno.h>
@@ -32,14 +33,6 @@
 # define SA_RESTART 0
 #endif
 
-typedef struct {
-  uv_signal_t* handle;
-  int signum;
-} uv__signal_msg_t;
-
-RB_HEAD(uv__signal_tree_s, uv_signal_s);
-
-
 static int uv__signal_unlock(void);
 static int uv__signal_start(uv_signal_t* handle,
                             uv_signal_cb signal_cb,
@@ -50,12 +43,6 @@ static int uv__signal_compare(uv_signal_t* w1, uv_signal_t* w2);
 static void uv__signal_stop(uv_signal_t* handle);
 static void uv__signal_unregister_handler(int signum);
 
-
-static uv_once_t uv__signal_global_init_guard = UV_ONCE_INIT;
-static struct uv__signal_tree_s uv__signal_tree =
-    RB_INITIALIZER(uv__signal_tree);
-static int uv__signal_lock_pipefd[2] = { -1, -1 };
-
 RB_GENERATE_STATIC(uv__signal_tree_s,
                    uv_signal_s, tree_entry,
                    uv__signal_compare)
diff --git a/src/unix/thread.c b/src/unix/thread.c
old mode 100644
new mode 100755
diff --git a/src/unix/tty.c b/src/unix/tty.c
index 9442cf16..bb7170bc 100644
--- a/src/unix/tty.c
+++ b/src/unix/tty.c
@@ -66,6 +66,7 @@ static int orig_termios_fd = -1;
 static struct termios orig_termios;
 static uv_spinlock_t termios_spinlock = UV_SPINLOCK_INITIALIZER;
 
+#ifndef __NuttX__
 static int uv__tty_is_slave(const int fd) {
   int result;
 #if defined(__linux__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
@@ -119,15 +120,13 @@ static int uv__tty_is_slave(const int fd) {
 #endif
   return result;
 }
+#endif
 
 int uv_tty_init(uv_loop_t* loop, uv_tty_t* tty, int fd, int unused) {
   uv_handle_type type;
   int flags;
-  int newfd;
-  int r;
   int saved_flags;
   int mode;
-  char path[256];
   (void)unused; /* deprecated parameter is no longer needed */
 
   /* File descriptors that refer to files cannot be monitored with epoll.
@@ -139,7 +138,6 @@ int uv_tty_init(uv_loop_t* loop, uv_tty_t* tty, int fd, int unused) {
     return UV_EINVAL;
 
   flags = 0;
-  newfd = -1;
 
   /* Save the fd flags in case we need to restore them due to an error. */
   do
@@ -150,6 +148,7 @@ int uv_tty_init(uv_loop_t* loop, uv_tty_t* tty, int fd, int unused) {
     return UV__ERR(errno);
   mode = saved_flags & O_ACCMODE;
 
+#ifndef __NuttX__
   /* Reopen the file descriptor when it refers to a tty. This lets us put the
    * tty in non-blocking mode without affecting other processes that share it
    * with us.
@@ -161,6 +160,10 @@ int uv_tty_init(uv_loop_t* loop, uv_tty_t* tty, int fd, int unused) {
    * other processes.
    */
   if (type == UV_TTY) {
+    int newfd;
+    int r;
+    char path[256];
+
     /* Reopening a pty in master mode won't work either because the reopened
      * pty will be in slave mode (*BSD) or reopening will allocate a new
      * master/slave pair (Linux). Therefore check if the fd points to a
@@ -194,6 +197,7 @@ int uv_tty_init(uv_loop_t* loop, uv_tty_t* tty, int fd, int unused) {
   }
 
 skip:
+#endif
   uv__stream_init(loop, (uv_stream_t*) tty, UV_TTY);
 
   /* If anything fails beyond this point we need to remove the handle from
diff --git a/src/unix/udp.c b/src/unix/udp.c
index 49051c07..dbd8a2c7 100644
--- a/src/unix/udp.c
+++ b/src/unix/udp.c
@@ -932,6 +932,7 @@ static int uv__udp_set_source_membership6(uv_udp_t* handle,
                                           const char* interface_addr,
                                           const struct sockaddr_in6* source_addr,
                                           uv_membership membership) {
+#ifndef __NuttX__
   struct group_source_req mreq;
   struct sockaddr_in6 addr6;
   int optname;
@@ -973,6 +974,9 @@ static int uv__udp_set_source_membership6(uv_udp_t* handle,
   }
 
   return 0;
+#else
+  return UV_ENOSYS;
+#endif
 }
 #endif
 
diff --git a/src/uv-common.c b/src/uv-common.c
index e81ed79b..d105db1f 100644
--- a/src/uv-common.c
+++ b/src/uv-common.c
@@ -21,6 +21,7 @@
 
 #include "uv.h"
 #include "uv-common.h"
+#include "uv-global.h"
 
 #include <assert.h>
 #include <errno.h>
@@ -756,10 +757,6 @@ int uv_loop_configure(uv_loop_t* loop, uv_loop_option option, ...) {
 }
 
 
-static uv_loop_t default_loop_struct;
-static uv_loop_t* default_loop_ptr;
-
-
 uv_loop_t* uv_default_loop(void) {
   if (default_loop_ptr != NULL)
     return default_loop_ptr;
@@ -880,8 +877,6 @@ void uv_free_cpu_info(uv_cpu_info_t* cpu_infos, int count) {
 __attribute__((destructor))
 #endif
 void uv_library_shutdown(void) {
-  static int was_shutdown;
-
   if (uv__load_relaxed(&was_shutdown))
     return;
 
@@ -949,3 +944,22 @@ uint64_t uv_metrics_idle_time(uv_loop_t* loop) {
     idle_time += uv_hrtime() - entry_time;
   return idle_time;
 }
+
+/* Add uv_global_get here since all system need it but NuttX */
+
+#ifndef __NuttX__
+#undef once
+#undef uv__signal_global_init_guard
+#undef uv__signal_lock_pipefd
+
+uv__global_t* uv__global_get(void)
+{
+  static uv__global_t g_uv_common_global = {
+    .once = UV_ONCE_INIT,
+    .uv__signal_global_init_guard = UV_ONCE_INIT,
+    .uv__signal_lock_pipefd = {-1, -1},
+  };
+
+  return &g_uv_common_global;
+}
+#endif
diff --git a/src/uv-global.h b/src/uv-global.h
new file mode 100644
index 00000000..458fe8ef
--- /dev/null
+++ b/src/uv-global.h
@@ -0,0 +1,92 @@
+/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef UV_GLOBAL_H
+#define UV_GLOBAL_H
+
+#include "uv.h"
+
+#if !defined(_WIN32)
+typedef struct {
+  uv_signal_t* handle;
+  int signum;
+} uv__signal_msg_t;
+
+RB_HEAD(uv__signal_tree_s, uv_signal_s);
+#endif
+
+typedef struct {
+  /* Member in threadpool.c */
+  uv_once_t once;
+  uv_cond_t cond;
+  uv_mutex_t mutex;
+  unsigned int idle_threads;
+  unsigned int slow_io_work_running;
+  unsigned int nthreads;
+  uv_thread_t* threads;
+  uv_thread_t default_threads[4];
+  QUEUE exit_message;
+  QUEUE wq;
+  QUEUE run_slow_work_message;
+  QUEUE slow_io_pending_wq;
+  /* Member in uv-common.c */
+  int was_shutdown;
+  uv_loop_t default_loop_struct;
+  uv_loop_t* default_loop_ptr;
+#if !defined(_WIN32)
+  /* Member in signal.c */
+  uv_once_t uv__signal_global_init_guard;
+  struct uv__signal_tree_s uv__signal_tree;
+  int uv__signal_lock_pipefd[2];
+#endif
+} uv__global_t;
+
+uv__global_t* uv__global_get(void);
+
+/* Used in threadpool.c */
+
+#define once uv__global_get()->once
+#define cond uv__global_get()->cond
+#define mutex uv__global_get()->mutex
+#define idle_threads uv__global_get()->idle_threads
+#define slow_io_work_running uv__global_get()->slow_io_work_running
+#define nthreads uv__global_get()->nthreads
+#define threads uv__global_get()->threads
+#define default_threads uv__global_get()->default_threads
+#define exit_message uv__global_get()->exit_message
+#define lwq uv__global_get()->wq
+#define run_slow_work_message uv__global_get()->run_slow_work_message
+#define slow_io_pending_wq uv__global_get()->slow_io_pending_wq
+
+/* Used in uv-common.c */
+
+#define was_shutdown uv__global_get()->was_shutdown
+#define default_loop_struct uv__global_get()->default_loop_struct
+#define default_loop_ptr uv__global_get()->default_loop_ptr
+
+#if !defined(_WIN32)
+/* Used in signal.c */
+
+#define uv__signal_global_init_guard uv__global_get()->uv__signal_global_init_guard
+#define uv__signal_tree uv__global_get()->uv__signal_tree
+#define uv__signal_lock_pipefd uv__global_get()->uv__signal_lock_pipefd
+#endif
+
+#endif
diff --git a/test/run-tests.c b/test/run-tests.c
index 5e53aaa8..cc7c1e81 100644
--- a/test/run-tests.c
+++ b/test/run-tests.c
@@ -66,7 +66,7 @@ typedef BOOL (WINAPI *sCompareObjectHandles)(_In_ HANDLE, _In_ HANDLE);
 
 
 int main(int argc, char **argv) {
-#ifndef _WIN32
+#if !defined(_WIN32) && !defined(__NuttX__)
   if (0 == geteuid() && NULL == getenv("UV_RUN_AS_ROOT")) {
     fprintf(stderr, "The libuv test suite cannot be run as root.\n");
     return EXIT_FAILURE;
diff --git a/test/runner-unix.c b/test/runner-unix.c
index a13648bc..c0b33b41 100644
--- a/test/runner-unix.c
+++ b/test/runner-unix.c
@@ -39,8 +39,7 @@
 #include <sys/select.h>
 #include <sys/time.h>
 #include <pthread.h>
-
-extern char** environ;
+#include <spawn.h>
 
 static void closefd(int fd) {
   if (close(fd) == 0 || errno == EINTR || errno == EINPROGRESS)
@@ -79,6 +78,7 @@ void platform_init(int argc, char **argv) {
 /* Invoke "argv[0] test-name [test-part]". Store process info in *p. Make sure
  * that all stdio output of the processes is buffered up. */
 int process_start(char* name, char* part, process_info_t* p, int is_helper) {
+  posix_spawn_file_actions_t file_actions;
   FILE* stdout_file;
   int stdout_fd;
   const char* arg;
@@ -115,12 +115,17 @@ int process_start(char* name, char* part, process_info_t* p, int is_helper) {
     return -1;
   }
 
+  posix_spawn_file_actions_init(&file_actions);
+  posix_spawn_file_actions_adddup2(&file_actions, stdout_fd, STDOUT_FILENO);
+  posix_spawn_file_actions_adddup2(&file_actions, stdout_fd, STDERR_FILENO);
+
   if (is_helper) {
     if (pipe(pipefd)) {
       perror("pipe");
       return -1;
     }
 
+    posix_spawn_file_actions_addclose(&file_actions, pipefd[0]);
     snprintf(fdstr, sizeof(fdstr), "%d", pipefd[1]);
     if (setenv("UV_TEST_RUNNER_FD", fdstr, /* overwrite */ 1)) {
       perror("setenv");
@@ -131,25 +136,13 @@ int process_start(char* name, char* part, process_info_t* p, int is_helper) {
   p->terminated = 0;
   p->status = 0;
 
-  pid = fork();
-
-  if (pid < 0) {
-    perror("fork");
+  n = posix_spawn(&pid, args[0], &file_actions, NULL, args, environ);
+  posix_spawn_file_actions_destroy(&file_actions);
+  if (n != 0) {
+    fprintf(stderr, "posix_spawn: %s\n", strerror(n));
     return -1;
   }
 
-  if (pid == 0) {
-    /* child */
-    if (is_helper)
-      closefd(pipefd[0]);
-    dup2(stdout_fd, STDOUT_FILENO);
-    dup2(stdout_fd, STDERR_FILENO);
-    execve(args[0], args, environ);
-    perror("execve()");
-    _exit(127);
-  }
-
-  /* parent */
   p->pid = pid;
   p->name = strdup(name);
   p->stdout_file = stdout_file;
diff --git a/test/task.h b/test/task.h
index a02c8931..997e55b2 100644
--- a/test/task.h
+++ b/test/task.h
@@ -100,6 +100,7 @@ typedef enum {
 /* Have our own assert, so we are sure it does not get optimized away in
  * a release build.
  */
+#undef ASSERT
 #define ASSERT(expr)                                      \
  do {                                                     \
   if (!(expr)) {                                          \
@@ -313,6 +314,7 @@ enum test_status {
 extern int snprintf(char*, size_t, const char*, ...);
 #endif
 
+#undef UNUSED
 #if defined(__clang__) ||                                \
     defined(__GNUC__) ||                                 \
     defined(__INTEL_COMPILER)
diff --git a/test/test-active.c b/test/test-active.c
index 38438956..aed8a36e 100644
--- a/test/test-active.c
+++ b/test/test-active.c
@@ -44,6 +44,8 @@ TEST_IMPL(active) {
   int r;
   uv_timer_t timer;
 
+  close_cb_called = 0;
+
   r = uv_timer_init(uv_default_loop(), &timer);
   ASSERT(r == 0);
 
diff --git a/test/test-async-null-cb.c b/test/test-async-null-cb.c
index 52652d91..2b341c4a 100644
--- a/test/test-async-null-cb.c
+++ b/test/test-async-null-cb.c
@@ -52,6 +52,8 @@ TEST_IMPL(async_null_cb) {
    */
   memset(&async_handle, 0xff, sizeof(async_handle));
 
+  check_cb_called = 0;
+
   ASSERT(0 == uv_async_init(uv_default_loop(), &async_handle, NULL));
   ASSERT(0 == uv_check_init(uv_default_loop(), &check_handle));
   ASSERT(0 == uv_check_start(&check_handle, check_cb));
diff --git a/test/test-async.c b/test/test-async.c
index 619be620..fee1ddd1 100644
--- a/test/test-async.c
+++ b/test/test-async.c
@@ -108,6 +108,10 @@ static void prepare_cb(uv_prepare_t* handle) {
 TEST_IMPL(async) {
   int r;
 
+  async_cb_called = 0;
+  close_cb_called = 0;
+  prepare_cb_called = 0;
+
   r = uv_mutex_init(&mutex);
   ASSERT(r == 0);
   uv_mutex_lock(&mutex);
diff --git a/test/test-close-order.c b/test/test-close-order.c
index c2fd6c3d..7a8111f0 100644
--- a/test/test-close-order.c
+++ b/test/test-close-order.c
@@ -56,6 +56,11 @@ static void timer_cb(uv_timer_t* handle) {
 
 TEST_IMPL(close_order) {
   uv_loop_t* loop;
+
+  check_cb_called = 0;
+  timer_cb_called = 0;
+  close_cb_called = 0;
+
   loop = uv_default_loop();
 
   uv_check_init(loop, &check_handle);
diff --git a/test/test-default-loop-close.c b/test/test-default-loop-close.c
index 51e1e7dc..fd9ad810 100644
--- a/test/test-default-loop-close.c
+++ b/test/test-default-loop-close.c
@@ -36,6 +36,8 @@ TEST_IMPL(default_loop_close) {
   uv_loop_t* loop;
   uv_timer_t timer_handle;
 
+  timer_cb_called = 0;
+
   loop = uv_default_loop();
   ASSERT_NOT_NULL(loop);
 
diff --git a/test/test-fs-copyfile.c b/test/test-fs-copyfile.c
index fa00fe4e..e7e1a409 100644
--- a/test/test-fs-copyfile.c
+++ b/test/test-fs-copyfile.c
@@ -25,7 +25,8 @@
 #if defined(__unix__) || defined(__POSIX__) || \
     defined(__APPLE__) || defined(__sun) || \
     defined(_AIX) || defined(__MVS__) || \
-    defined(__HAIKU__) || defined(__QNX__)
+    defined(__HAIKU__) || defined(__QNX__) || \
+    defined(__NuttX__)
 #include <unistd.h> /* unlink, etc. */
 #else
 # include <direct.h>
diff --git a/test/test-idle.c b/test/test-idle.c
index f49d1964..91a20bd2 100644
--- a/test/test-idle.c
+++ b/test/test-idle.c
@@ -72,6 +72,11 @@ static void check_cb(uv_check_t* handle) {
 TEST_IMPL(idle_starvation) {
   int r;
 
+  idle_cb_called = 0;
+  check_cb_called = 0;
+  timer_cb_called = 0;
+  close_cb_called = 0;
+
   r = uv_idle_init(uv_default_loop(), &idle_handle);
   ASSERT(r == 0);
   r = uv_idle_start(&idle_handle, idle_cb);
diff --git a/test/test-list.h b/test/test-list.h
index 59b95da9..33867697 100644
--- a/test/test-list.h
+++ b/test/test-list.h
@@ -573,7 +573,7 @@ TASK_LIST_START
   TEST_ENTRY  (pipe_connect_on_prepare)
 
   TEST_ENTRY  (pipe_server_close)
-#ifndef _WIN32
+#if !defined(_WIN32) && !defined(__NuttX__)
   TEST_ENTRY  (pipe_close_stdout_read_stdin)
 #endif
   /* Seems to be either about 0.5s or 5s, depending on the OS. */
@@ -1112,7 +1112,7 @@ TASK_LIST_START
   TEST_ENTRY  (req_type_name)
   TEST_ENTRY  (getters_setters)
 
-#ifndef _WIN32
+#if !defined(_WIN32) && !defined(__NuttX__)
   TEST_ENTRY  (fork_timer)
   TEST_ENTRY  (fork_socketpair)
   TEST_ENTRY  (fork_socketpair_started)
diff --git a/test/test-loop-alive.c b/test/test-loop-alive.c
index cf4d3019..9a7b1024 100644
--- a/test/test-loop-alive.c
+++ b/test/test-loop-alive.c
@@ -63,5 +63,6 @@ TEST_IMPL(loop_alive) {
   ASSERT(r == 0);
   ASSERT(!uv_loop_alive(uv_default_loop()));
 
+  MAKE_VALGRIND_HAPPY();
   return 0;
 }
diff --git a/test/test-loop-close.c b/test/test-loop-close.c
index f0f3e627..d3f8748f 100644
--- a/test/test-loop-close.c
+++ b/test/test-loop-close.c
@@ -53,6 +53,7 @@ TEST_IMPL(loop_close) {
   ASSERT(0 == uv_loop_close(&loop));
   ASSERT(loop.data == (void*) &loop);
 
+  MAKE_VALGRIND_HAPPY();
   return 0;
 }
 
diff --git a/test/test-loop-configure.c b/test/test-loop-configure.c
index d057c1ed..1633f597 100644
--- a/test/test-loop-configure.c
+++ b/test/test-loop-configure.c
@@ -25,7 +25,7 @@ TEST_IMPL(loop_configure) {
   uv_timer_t timer_handle;
   uv_loop_t loop;
   ASSERT(0 == uv_loop_init(&loop));
-#ifdef _WIN32
+#ifndef SIGPROF
   ASSERT(UV_ENOSYS == uv_loop_configure(&loop, UV_LOOP_BLOCK_SIGNAL, 0));
 #else
   ASSERT(0 == uv_loop_configure(&loop, UV_LOOP_BLOCK_SIGNAL, SIGPROF));
diff --git a/test/test-loop-handles.c b/test/test-loop-handles.c
index 05cb8466..5db583b5 100644
--- a/test/test-loop-handles.c
+++ b/test/test-loop-handles.c
@@ -282,6 +282,21 @@ TEST_IMPL(loop_handles) {
   int i;
   int r;
 
+  loop_iteration = 0;
+  prepare_1_cb_called = 0;
+  prepare_1_close_cb_called = 0;
+  prepare_2_cb_called = 0;
+  prepare_2_close_cb_called = 0;
+  check_cb_called = 0;
+  check_close_cb_called = 0;
+  idle_1_cb_called = 0;
+  idle_1_close_cb_called = 0;
+  idles_1_active = 0;
+  idle_2_cb_called = 0;
+  idle_2_close_cb_called = 0;
+  idle_2_cb_started = 0;
+  idle_2_is_active = 0;
+
   r = uv_prepare_init(uv_default_loop(), &prepare_1_handle);
   ASSERT(r == 0);
   r = uv_prepare_start(&prepare_1_handle, prepare_1_cb);
diff --git a/test/test-loop-stop.c b/test/test-loop-stop.c
index 14b8c111..6aa251fd 100644
--- a/test/test-loop-stop.c
+++ b/test/test-loop-stop.c
@@ -49,6 +49,11 @@ static void timer_cb(uv_timer_t* handle) {
 
 TEST_IMPL(loop_stop) {
   int r;
+
+  prepare_called = 0;
+  timer_called = 0;
+  num_ticks = 10;
+
   uv_prepare_init(uv_default_loop(), &prepare_handle);
   uv_prepare_start(&prepare_handle, prepare_cb);
   uv_timer_init(uv_default_loop(), &timer_handle);
@@ -67,5 +72,6 @@ TEST_IMPL(loop_stop) {
   ASSERT(timer_called == 10);
   ASSERT(prepare_called == 10);
 
+  MAKE_VALGRIND_HAPPY();
   return 0;
 }
diff --git a/test/test-pipe-connect-error.c b/test/test-pipe-connect-error.c
index 30c270d9..0e9eea30 100644
--- a/test/test-pipe-connect-error.c
+++ b/test/test-pipe-connect-error.c
@@ -35,6 +35,11 @@
 static int close_cb_called = 0;
 static int connect_cb_called = 0;
 
+static void init_globals(void)
+{
+  close_cb_called = 0;
+  connect_cb_called = 0;
+}
 
 static void close_cb(uv_handle_t* handle) {
   ASSERT_NOT_NULL(handle);
@@ -61,6 +66,7 @@ TEST_IMPL(pipe_connect_bad_name) {
   uv_connect_t req;
   int r;
 
+  init_globals();
   r = uv_pipe_init(uv_default_loop(), &client, 0);
   ASSERT(r == 0);
   uv_pipe_connect(&req, &client, BAD_PIPENAME, connect_cb);
@@ -84,6 +90,7 @@ TEST_IMPL(pipe_connect_to_file) {
   uv_connect_t req;
   int r;
 
+  init_globals();
   r = uv_pipe_init(uv_default_loop(), &client, 0);
   ASSERT(r == 0);
   uv_pipe_connect(&req, &client, path, connect_cb_file);
diff --git a/test/test-pipe-connect-prepare.c b/test/test-pipe-connect-prepare.c
index 08b57cbf..e6975b95 100644
--- a/test/test-pipe-connect-prepare.c
+++ b/test/test-pipe-connect-prepare.c
@@ -64,6 +64,9 @@ static void prepare_cb(uv_prepare_t* handle) {
 TEST_IMPL(pipe_connect_on_prepare) {
   int r;
 
+  close_cb_called = 0;
+  connect_cb_called = 0;
+
   r = uv_pipe_init(uv_default_loop(), &pipe_handle, 0);
   ASSERT(r == 0);
 
diff --git a/test/test-queue-foreach-delete.c b/test/test-queue-foreach-delete.c
index 049ea776..2b54de1d 100644
--- a/test/test-queue-foreach-delete.c
+++ b/test/test-queue-foreach-delete.c
@@ -101,6 +101,9 @@ static const unsigned first_handle_number_fs_event = 0;
 #define INIT_AND_START(name, loop)                                            \
   do {                                                                        \
     size_t i;                                                                 \
+    name##_cb_calls[0] = 0;                                                   \
+    name##_cb_calls[1] = 0;                                                   \
+    name##_cb_calls[2] = 0;                                                   \
     for (i = 0; i < ARRAY_SIZE(name); i++) {                                  \
       int r;                                                                  \
       r = uv_##name##_init((loop), &(name)[i]);                               \
diff --git a/test/test-random.c b/test/test-random.c
index 2e3ce442..6736c342 100644
--- a/test/test-random.c
+++ b/test/test-random.c
@@ -53,6 +53,9 @@ TEST_IMPL(random_async) {
   uv_random_t req;
   uv_loop_t* loop;
 
+  random_cb_called = 0;
+  memset(scratch, 0, sizeof(scratch));
+
   loop = uv_default_loop();
   ASSERT(UV_EINVAL == uv_random(loop, &req, scratch, sizeof(scratch), -1,
                                 random_cb));
@@ -79,6 +82,9 @@ TEST_IMPL(random_sync) {
   char zero[256];
   char buf[256];
 
+  random_cb_called = 0;
+  memset(scratch, 0, sizeof(scratch));
+
   ASSERT(UV_EINVAL == uv_random(NULL, NULL, buf, sizeof(buf), -1, NULL));
   ASSERT(UV_E2BIG == uv_random(NULL, NULL, buf, -1, -1, NULL));
 
diff --git a/test/test-run-nowait.c b/test/test-run-nowait.c
index 43524f63..9f2645b5 100644
--- a/test/test-run-nowait.c
+++ b/test/test-run-nowait.c
@@ -34,6 +34,9 @@ static void timer_cb(uv_timer_t* handle) {
 
 TEST_IMPL(run_nowait) {
   int r;
+
+  timer_called = 0;
+
   uv_timer_init(uv_default_loop(), &timer_handle);
   uv_timer_start(&timer_handle, timer_cb, 100, 100);
 
@@ -41,5 +44,6 @@ TEST_IMPL(run_nowait) {
   ASSERT(r != 0);
   ASSERT(timer_called == 0);
 
+  MAKE_VALGRIND_HAPPY();
   return 0;
 }
diff --git a/test/test-run-once.c b/test/test-run-once.c
index 10cbf95e..7de04a91 100644
--- a/test/test-run-once.c
+++ b/test/test-run-once.c
@@ -37,6 +37,9 @@ static void idle_cb(uv_idle_t* handle) {
 
 
 TEST_IMPL(run_once) {
+
+  idle_counter = 0;
+
   uv_idle_init(uv_default_loop(), &idle_handle);
   uv_idle_start(&idle_handle, idle_cb);
 
diff --git a/test/test-strscpy.c b/test/test-strscpy.c
index 4e7db6ff..f1d3e3ac 100644
--- a/test/test-strscpy.c
+++ b/test/test-strscpy.c
@@ -24,7 +24,9 @@
 #include <string.h>
 
 #include "../src/strscpy.h"
+#ifndef __NuttX__
 #include "../src/strscpy.c"
+#endif
 
 TEST_IMPL(strscpy) {
   char d[4];
diff --git a/test/test-thread.c b/test/test-thread.c
index 8de5a6f0..11e3cf80 100644
--- a/test/test-thread.c
+++ b/test/test-thread.c
@@ -61,6 +61,11 @@ static void fs_cb(uv_fs_t* handle);
 static int thread_called;
 static uv_key_t tls_key;
 
+static void init_globals(void)
+{
+  thread_called = 0;
+  tls_key = 0;
+}
 
 static void getaddrinfo_do(struct getaddrinfo_req* req) {
   int r;
@@ -151,6 +156,8 @@ TEST_IMPL(thread_create) {
   uv_thread_t tid;
   int r;
 
+  init_globals();
+
   r = uv_thread_create(&tid, thread_entry, (void *) 42);
   ASSERT(r == 0);
 
@@ -172,6 +179,7 @@ TEST_IMPL(threadpool_multiple_event_loops) {
   RETURN_SKIP("Test does not currently work in QEMU");
 #endif
   
+  init_globals();
   struct test_thread threads[8];
   size_t i;
   int r;
@@ -205,6 +213,7 @@ static void tls_thread(void* arg) {
 TEST_IMPL(thread_local_storage) {
   char name[] = "main";
   uv_thread_t threads[2];
+  init_globals();
   ASSERT(0 == uv_key_create(&tls_key));
   ASSERT_NULL(uv_key_get(&tls_key));
   uv_key_set(&tls_key, name);
@@ -248,6 +257,7 @@ static void thread_check_stack(void* arg) {
 
 TEST_IMPL(thread_stack_size) {
   uv_thread_t thread;
+  init_globals();
   ASSERT(0 == uv_thread_create(&thread, thread_check_stack, NULL));
   ASSERT(0 == uv_thread_join(&thread));
   return 0;
@@ -257,6 +267,7 @@ TEST_IMPL(thread_stack_size_explicit) {
   uv_thread_t thread;
   uv_thread_options_t options;
 
+  init_globals();
   options.flags = UV_THREAD_HAS_STACK_SIZE;
   options.stack_size = 1024 * 1024;
   ASSERT(0 == uv_thread_create_ex(&thread, &options,
diff --git a/test/test-threadpool-cancel.c b/test/test-threadpool-cancel.c
index 1e867c51..955d49b3 100644
--- a/test/test-threadpool-cancel.c
+++ b/test/test-threadpool-cancel.c
@@ -49,6 +49,13 @@ static unsigned timer_cb_called;
 static uv_work_t pause_reqs[4];
 static uv_sem_t pause_sems[ARRAY_SIZE(pause_reqs)];
 
+static void init_globals(void)
+{
+  fs_cb_called = 0;
+  done_cb_called = 0;
+  done2_cb_called = 0;
+  timer_cb_called = 0;
+}
 
 static void work_cb(uv_work_t* req) {
   uv_sem_wait(pause_sems + (req - pause_reqs));
@@ -168,6 +175,8 @@ TEST_IMPL(threadpool_cancel_getaddrinfo) {
   uv_loop_t* loop;
   int r;
 
+  init_globals();
+
   INIT_CANCEL_INFO(&ci, reqs);
   loop = uv_default_loop();
   saturate_threadpool();
@@ -201,6 +210,8 @@ TEST_IMPL(threadpool_cancel_getnameinfo) {
   uv_loop_t* loop;
   int r;
 
+  init_globals();
+
   r = uv_ip4_addr("127.0.0.1", 80, &addr4);
   ASSERT(r == 0);
 
@@ -234,6 +245,8 @@ TEST_IMPL(threadpool_cancel_random) {
   struct random_info req;
   uv_loop_t* loop;
 
+  init_globals();
+
   saturate_threadpool();
   loop = uv_default_loop();
   ASSERT(0 == uv_random(loop,
@@ -259,6 +272,8 @@ TEST_IMPL(threadpool_cancel_work) {
   uv_loop_t* loop;
   unsigned i;
 
+  init_globals();
+
   INIT_CANCEL_INFO(&ci, reqs);
   loop = uv_default_loop();
   saturate_threadpool();
@@ -284,6 +299,8 @@ TEST_IMPL(threadpool_cancel_fs) {
   unsigned n;
   uv_buf_t iov;
 
+  init_globals();
+
   INIT_CANCEL_INFO(&ci, reqs);
   loop = uv_default_loop();
   saturate_threadpool();
@@ -335,6 +352,8 @@ TEST_IMPL(threadpool_cancel_single) {
   uv_loop_t* loop;
   uv_work_t req;
 
+  init_globals();
+
   saturate_threadpool();
   loop = uv_default_loop();
   ASSERT(0 == uv_queue_work(loop, &req, (uv_work_cb) abort, nop_done_cb));
diff --git a/test/test-threadpool.c b/test/test-threadpool.c
index e3d17d75..845c4b6a 100644
--- a/test/test-threadpool.c
+++ b/test/test-threadpool.c
@@ -27,6 +27,11 @@ static int after_work_cb_count;
 static uv_work_t work_req;
 static char data;
 
+static void init_globals(void)
+{
+  work_cb_count = 0;
+  after_work_cb_count = 0;
+}
 
 static void work_cb(uv_work_t* req) {
   ASSERT(req == &work_req);
@@ -46,6 +51,8 @@ static void after_work_cb(uv_work_t* req, int status) {
 TEST_IMPL(threadpool_queue_work_simple) {
   int r;
 
+  init_globals();
+
   work_req.data = &data;
   r = uv_queue_work(uv_default_loop(), &work_req, work_cb, after_work_cb);
   ASSERT(r == 0);
@@ -62,6 +69,8 @@ TEST_IMPL(threadpool_queue_work_simple) {
 TEST_IMPL(threadpool_queue_work_einval) {
   int r;
 
+  init_globals();
+
   work_req.data = &data;
   r = uv_queue_work(uv_default_loop(), &work_req, NULL, after_work_cb);
   ASSERT(r == UV_EINVAL);
diff --git a/test/test-timer-again.c b/test/test-timer-again.c
index 834b59d7..cffc2e07 100644
--- a/test/test-timer-again.c
+++ b/test/test-timer-again.c
@@ -95,6 +95,11 @@ static void repeat_2_cb(uv_timer_t* handle) {
 TEST_IMPL(timer_again) {
   int r;
 
+  close_cb_called = 0;
+  repeat_1_cb_called = 0;
+  repeat_2_cb_called = 0;
+  repeat_2_cb_allowed = 0;
+
   start_time = uv_now(uv_default_loop());
   ASSERT(0 < start_time);
 
diff --git a/test/test-timer-from-check.c b/test/test-timer-from-check.c
index a18c7e1f..745eec4d 100644
--- a/test/test-timer-from-check.c
+++ b/test/test-timer-from-check.c
@@ -62,6 +62,11 @@ static void check_cb(uv_check_t* handle) {
 
 
 TEST_IMPL(timer_from_check) {
+
+  prepare_cb_called = 0;
+  check_cb_called = 0;
+  timer_cb_called = 0;
+
   ASSERT(0 == uv_prepare_init(uv_default_loop(), &prepare_handle));
   ASSERT(0 == uv_check_init(uv_default_loop(), &check_handle));
   ASSERT(0 == uv_check_start(&check_handle, check_cb));
diff --git a/test/test-timer.c b/test/test-timer.c
index d0921a96..a9cb2731 100644
--- a/test/test-timer.c
+++ b/test/test-timer.c
@@ -32,6 +32,17 @@ static uint64_t start_time;
 static uv_timer_t tiny_timer;
 static uv_timer_t huge_timer1;
 static uv_timer_t huge_timer2;
+static int ncalls = 0;
+
+void init_globals(void)
+{
+  once_cb_called = 0;
+  once_close_cb_called = 0;
+  repeat_cb_called = 0;
+  repeat_close_cb_called = 0;
+  order_cb_called = 0;
+  ncalls = 0;
+}
 
 
 static void once_close_cb(uv_handle_t* handle) {
@@ -94,6 +105,8 @@ TEST_IMPL(timer) {
   unsigned int i;
   int r;
 
+  init_globals();
+
   start_time = uv_now(uv_default_loop());
   ASSERT(0 < start_time);
 
@@ -140,6 +153,8 @@ TEST_IMPL(timer_start_twice) {
   uv_timer_t once;
   int r;
 
+  init_globals();
+
   r = uv_timer_init(uv_default_loop(), &once);
   ASSERT(r == 0);
   r = uv_timer_start(&once, never_cb, 86400 * 1000, 0);
@@ -159,6 +174,8 @@ TEST_IMPL(timer_start_twice) {
 TEST_IMPL(timer_init) {
   uv_timer_t handle;
 
+  init_globals();
+
   ASSERT(0 == uv_timer_init(uv_default_loop(), &handle));
   ASSERT(0 == uv_timer_get_repeat(&handle));
   ASSERT_UINT64_LE(0, uv_timer_get_due_in(&handle));
@@ -185,6 +202,8 @@ TEST_IMPL(timer_order) {
   uv_timer_t handle_a;
   uv_timer_t handle_b;
 
+  init_globals();
+
   first = 0;
   second = 1;
   ASSERT(0 == uv_timer_init(uv_default_loop(), &handle_a));
@@ -227,6 +246,9 @@ static void tiny_timer_cb(uv_timer_t* handle) {
 
 
 TEST_IMPL(timer_huge_timeout) {
+
+  init_globals();
+
   ASSERT(0 == uv_timer_init(uv_default_loop(), &tiny_timer));
   ASSERT(0 == uv_timer_init(uv_default_loop(), &huge_timer1));
   ASSERT(0 == uv_timer_init(uv_default_loop(), &huge_timer2));
@@ -243,7 +265,6 @@ TEST_IMPL(timer_huge_timeout) {
 
 
 static void huge_repeat_cb(uv_timer_t* handle) {
-  static int ncalls;
 
   if (ncalls == 0)
     ASSERT(handle == &huge_timer1);
@@ -258,6 +279,9 @@ static void huge_repeat_cb(uv_timer_t* handle) {
 
 
 TEST_IMPL(timer_huge_repeat) {
+
+  init_globals();
+
   ASSERT(0 == uv_timer_init(uv_default_loop(), &tiny_timer));
   ASSERT(0 == uv_timer_init(uv_default_loop(), &huge_timer1));
   ASSERT(0 == uv_timer_start(&tiny_timer, huge_repeat_cb, 2, 2));
@@ -279,6 +303,10 @@ static void timer_run_once_timer_cb(uv_timer_t* handle) {
 TEST_IMPL(timer_run_once) {
   uv_timer_t timer_handle;
 
+  init_globals();
+
+  timer_run_once_timer_cb_called = 0;
+
   ASSERT(0 == uv_timer_init(uv_default_loop(), &timer_handle));
   ASSERT(0 == uv_timer_start(&timer_handle, timer_run_once_timer_cb, 0, 0));
   ASSERT(0 == uv_run(uv_default_loop(), UV_RUN_ONCE));
@@ -299,6 +327,8 @@ TEST_IMPL(timer_run_once) {
 TEST_IMPL(timer_is_closing) {
   uv_timer_t handle;
 
+  init_globals();
+
   ASSERT(0 == uv_timer_init(uv_default_loop(), &handle));
   uv_close((uv_handle_t *)&handle, NULL);
 
@@ -312,6 +342,8 @@ TEST_IMPL(timer_is_closing) {
 TEST_IMPL(timer_null_callback) {
   uv_timer_t handle;
 
+  init_globals();
+
   ASSERT(0 == uv_timer_init(uv_default_loop(), &handle));
   ASSERT(UV_EINVAL == uv_timer_start(&handle, NULL, 100, 100));
 
@@ -333,6 +365,8 @@ TEST_IMPL(timer_early_check) {
   uv_timer_t timer_handle;
   const uint64_t timeout_ms = 10;
 
+  init_globals();
+
   timer_early_check_expected_time = uv_now(uv_default_loop()) + timeout_ms;
 
   ASSERT(0 == uv_timer_init(uv_default_loop(), &timer_handle));