diff --git a/deps/uv/config-unix.mk b/deps/uv/config-unix.mk
index 73c9827a741..85605b85949 100644
--- a/deps/uv/config-unix.mk
+++ b/deps/uv/config-unix.mk
@@ -98,7 +98,7 @@ src/ev/ev.o: src/ev/ev.c
 
 EIO_CPPFLAGS += $(CPPFLAGS)
 EIO_CPPFLAGS += -DEIO_CONFIG_H=\"$(EIO_CONFIG)\"
-EIO_CPPFLAGS += -DEIO_STACKSIZE=65536
+EIO_CPPFLAGS += -DEIO_STACKSIZE=262144
 EIO_CPPFLAGS += -D_GNU_SOURCE
 
 src/eio/eio.o: src/eio/eio.c
diff --git a/deps/uv/include/uv-unix.h b/deps/uv/include/uv-unix.h
index 72c66a9f71f..2f084b27e78 100644
--- a/deps/uv/include/uv-unix.h
+++ b/deps/uv/include/uv-unix.h
@@ -88,6 +88,7 @@ typedef struct {
 #define UV_PIPE_PRIVATE_FIELDS \
   UV_TCP_PRIVATE_FIELDS \
   const char* pipe_fname; /* strdup'ed */ \
+  void* pipe_flock;
 
 
 /* UV_PREPARE */ \
diff --git a/deps/uv/include/uv.h b/deps/uv/include/uv.h
index d72caa6df83..46b03e1124f 100644
--- a/deps/uv/include/uv.h
+++ b/deps/uv/include/uv.h
@@ -508,9 +508,8 @@ typedef struct uv_process_options_s {
   char** env;
   char* cwd;
   /*
-   * The user should supply pointers to uninitialized uv_pipe_t structs for
-   * stdio. They will be initialized by uv_spawn. The user is reponsible for
-   * calling uv_close on them.
+   * The user should supply pointers to initialized uv_pipe_t structs for
+   * stdio. The user is reponsible for calling uv_close on them.
    */
   uv_pipe_t* stdin_stream;
   uv_pipe_t* stdout_stream;
diff --git a/deps/uv/src/eio/eio.c b/deps/uv/src/eio/eio.c
index 7f48add4019..9464e62ced3 100644
--- a/deps/uv/src/eio/eio.c
+++ b/deps/uv/src/eio/eio.c
@@ -40,7 +40,7 @@
 #include "eio.h"
 
 #ifdef EIO_STACKSIZE
-# define XTHREAD_STACKSIZE EIO_STACKSIZE
+# define X_STACKSIZE EIO_STACKSIZE
 #endif
 
 // For statically-linked pthreads-w32, use:
@@ -1270,6 +1270,10 @@ eio__scandir (eio_req *req, etp_worker *self)
   X_LOCK (wrklock);
   /* the corresponding closedir is in ETP_WORKER_CLEAR */
   self->dirp = dirp = opendir (req->ptr1);
+
+  if (req->flags & EIO_FLAG_PTR1_FREE)
+    free (req->ptr1);
+
   req->flags |= EIO_FLAG_PTR1_FREE | EIO_FLAG_PTR2_FREE;
   req->ptr1 = dents = flags ? malloc (dentalloc * sizeof (eio_dirent)) : 0;
   req->ptr2 = names = malloc (namesalloc);
diff --git a/deps/uv/src/uv-unix.c b/deps/uv/src/uv-unix.c
index 8d1c9420297..33903e0152d 100644
--- a/deps/uv/src/uv-unix.c
+++ b/deps/uv/src/uv-unix.c
@@ -35,6 +35,7 @@
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/file.h>
 #include <fcntl.h>
 #include <sys/socket.h>
 #include <sys/un.h>
@@ -42,6 +43,11 @@
 #include <arpa/inet.h>
 #include <limits.h> /* PATH_MAX */
 
+#ifdef __sun
+# include <sys/types.h>
+# include <sys/wait.h>
+#endif
+
 #if defined(__APPLE__)
 #include <mach-o/dyld.h> /* _NSGetExecutablePath */
 #endif
@@ -73,6 +79,32 @@ struct uv_ares_data_s {
 
 static struct uv_ares_data_s ares_data;
 
+typedef struct {
+  const char* lockfile;
+  int lockfd;
+} uv_flock_t;
+
+
+/* Create a new advisory file lock for `filename`.
+ * Call `uv_flock_acquire()` to actually acquire the lock.
+ */
+int uv_flock_init(uv_flock_t* lock, const char* filename);
+
+/* Try to acquire the file lock. Returns 0 on success, -1 on error.
+ * Does not wait for the lock to be released if it is held by another process.
+ *
+ * If `locked` is not NULL, the memory pointed it points to is set to 1 if
+ * the file is locked by another process. Only relevant in error scenarios.
+ */
+int uv_flock_acquire(uv_flock_t* lock, int* locked);
+
+/* Release the file lock. Returns 0 on success, -1 on error.
+ */
+int uv_flock_release(uv_flock_t* lock);
+
+/* Destroy the file lock. Releases the file lock and associated resources.
+ */
+int uv_flock_destroy(uv_flock_t* lock);
 
 void uv__req_init(uv_req_t*);
 void uv__next(EV_P_ ev_idle* watcher, int revents);
@@ -82,6 +114,7 @@ static uv_err_t uv_err_new(uv_handle_t* handle, int sys_error);
 
 static int uv_tcp_listen(uv_tcp_t* tcp, int backlog, uv_connection_cb cb);
 static int uv_pipe_listen(uv_pipe_t* handle, int backlog, uv_connection_cb cb);
+static int uv_pipe_cleanup(uv_pipe_t* handle);
 static uv_write_t* uv__write(uv_stream_t* stream);
 static void uv__read(uv_stream_t* stream);
 static void uv__stream_connect(uv_stream_t*);
@@ -241,17 +274,8 @@ void uv_close(uv_handle_t* handle, uv_close_cb close_cb) {
 
     case UV_NAMED_PIPE:
       pipe = (uv_pipe_t*)handle;
-      if (pipe->pipe_fname) {
-        /*
-         * Unlink the file system entity before closing the file descriptor.
-         * Doing it the other way around introduces a race where our process
-         * unlinks a socket with the same name that's just been created by
-         * another thread or process.
-         */
-        unlink(pipe->pipe_fname);
-        free((void*)pipe->pipe_fname);
-      }
-      uv_read_stop((uv_stream_t*)pipe);
+      uv_pipe_cleanup(pipe);
+      uv_read_stop((uv_stream_t*)handle);
       ev_io_stop(EV_DEFAULT_ &pipe->write_watcher);
       break;
 
@@ -1807,6 +1831,7 @@ int uv_pipe_init(uv_pipe_t* handle) {
   uv_counters()->pipe_init++;
 
   handle->type = UV_NAMED_PIPE;
+  handle->pipe_flock = NULL; /* Only set by listener. */
   handle->pipe_fname = NULL; /* Only set by listener. */
 
   ev_init(&handle->write_watcher, uv__stream_io);
@@ -1825,13 +1850,16 @@ int uv_pipe_init(uv_pipe_t* handle) {
 int uv_pipe_bind(uv_pipe_t* handle, const char* name) {
   struct sockaddr_un sun;
   const char* pipe_fname;
+  uv_flock_t* pipe_flock;
   int saved_errno;
+  int locked;
   int sockfd;
   int status;
   int bound;
 
   saved_errno = errno;
   pipe_fname = NULL;
+  pipe_flock = NULL;
   sockfd = -1;
   status = -1;
   bound = 0;
@@ -1851,6 +1879,20 @@ int uv_pipe_bind(uv_pipe_t* handle, const char* name) {
   /* We've got a copy, don't touch the original any more. */
   name = NULL;
 
+  /* Create and acquire a file lock for this UNIX socket. */
+  if ((pipe_flock = malloc(sizeof *pipe_flock)) == NULL
+      || uv_flock_init(pipe_flock, pipe_fname) == -1) {
+    uv_err_new((uv_handle_t*)handle, ENOMEM);
+    goto out;
+  }
+
+  if (uv_flock_acquire(pipe_flock, &locked) == -1) {
+    /* Another process holds the lock so the socket is in use. */
+    uv_err_new_artificial((uv_handle_t*)handle,
+                          locked ? UV_EADDRINUSE : UV_EACCESS);
+    goto out;
+  }
+
   if ((sockfd = uv__socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
     uv_err_new((uv_handle_t*)handle, errno);
     goto out;
@@ -1861,17 +1903,13 @@ int uv_pipe_bind(uv_pipe_t* handle, const char* name) {
   sun.sun_family = AF_UNIX;
 
   if (bind(sockfd, (struct sockaddr*)&sun, sizeof sun) == -1) {
-#ifdef DONT_RACE_ME_BRO
-    /*
-     * Try to bind the socket. Note that we explicitly don't act
-     * on EADDRINUSE. Unlinking and trying to bind again opens
-     * a window for races with other threads and processes.
-     */
-    uv_err_new((uv_handle_t*)handle, (errno == ENOENT) ? EACCES : errno);
-    goto out;
-#else
-    /*
-     * Try to re-purpose the socket. This is a potential race window.
+    /* On EADDRINUSE:
+     *
+     * We hold the file lock so there is no other process listening
+     * on the socket. Ergo, it's stale - remove it.
+     *
+     * This assumes that the other process uses locking too
+     * but that's a good enough assumption for now.
      */
     if (errno != EADDRINUSE
         || unlink(pipe_fname) == -1
@@ -1880,7 +1918,6 @@ int uv_pipe_bind(uv_pipe_t* handle, const char* name) {
       uv_err_new((uv_handle_t*)handle, (errno == ENOENT) ? EACCES : errno);
       goto out;
     }
-#endif
   }
   bound = 1;
 
@@ -1898,6 +1935,11 @@ out:
       unlink(pipe_fname);
     }
     uv__close(sockfd);
+
+    if (pipe_flock) {
+      uv_flock_destroy(pipe_flock);
+    }
+
     free((void*)pipe_fname);
   }
 
@@ -1914,7 +1956,7 @@ static int uv_pipe_listen(uv_pipe_t* handle, int backlog, uv_connection_cb cb) {
   status = -1;
 
   if (handle->fd == -1) {
-    uv_err_new_artificial((uv_handle_t*)handle, UV_ENOTCONN);
+    uv_err_new_artificial((uv_handle_t*)handle, UV_EINVAL);
     goto out;
   }
   assert(handle->fd >= 0);
@@ -1933,6 +1975,37 @@ out:
 }
 
 
+static int uv_pipe_cleanup(uv_pipe_t* handle) {
+  int saved_errno;
+  int status;
+
+  saved_errno = errno;
+  status = -1;
+
+  if (handle->pipe_fname) {
+    /*
+     * Unlink the file system entity before closing the file descriptor.
+     * Doing it the other way around introduces a race where our process
+     * unlinks a socket with the same name that's just been created by
+     * another thread or process.
+     *
+     * This is less of an issue now that we attach a file lock
+     * to the socket but it's still a best practice.
+     */
+    unlink(handle->pipe_fname);
+    free((void*)handle->pipe_fname);
+  }
+
+  if (handle->pipe_flock) {
+    uv_flock_destroy((uv_flock_t*)handle->pipe_flock);
+    free(handle->pipe_flock);
+  }
+
+  errno = saved_errno;
+  return status;
+}
+
+
 int uv_pipe_connect(uv_connect_t* req,
                     uv_pipe_t* handle,
                     const char* name,
@@ -2198,17 +2271,37 @@ int uv_spawn(uv_process_t* process, uv_process_options_t options) {
 
   process->exit_cb = options.exit_cb;
 
+  if (options.stdin_stream) {
+    if (options.stdin_stream->type != UV_NAMED_PIPE) {
+      errno = EINVAL;
+      goto error;
+    }
 
-  if (options.stdin_stream && pipe(stdin_pipe) < 0) {
-    goto error;
+    if (pipe(stdin_pipe) < 0) {
+      goto error;
+    }
   }
 
-  if (options.stdout_stream && pipe(stdout_pipe) < 0) {
-    goto error;
+  if (options.stdout_stream) {
+    if (options.stdout_stream->type != UV_NAMED_PIPE) {
+      errno = EINVAL;
+      goto error;
+    }
+
+    if (pipe(stdout_pipe) < 0) {
+      goto error;
+    }
   }
 
-  if (options.stderr_stream && pipe(stderr_pipe) < 0) {
-    goto error;
+  if (options.stderr_stream) {
+    if (options.stderr_stream->type != UV_NAMED_PIPE) {
+      errno = EINVAL;
+      goto error;
+    }
+
+    if (pipe(stderr_pipe) < 0) {
+      goto error;
+    }
   }
 
   pid = fork();
@@ -2262,7 +2355,6 @@ int uv_spawn(uv_process_t* process, uv_process_options_t options) {
     assert(stdin_pipe[0] >= 0);
     close(stdin_pipe[0]);
     uv__nonblock(stdin_pipe[1], 1);
-    uv_pipe_init(options.stdin_stream);
     uv__stream_open((uv_stream_t*)options.stdin_stream, stdin_pipe[1]);
   }
 
@@ -2271,7 +2363,6 @@ int uv_spawn(uv_process_t* process, uv_process_options_t options) {
     assert(stdout_pipe[1] >= 0);
     close(stdout_pipe[1]);
     uv__nonblock(stdout_pipe[0], 1);
-    uv_pipe_init(options.stdout_stream);
     uv__stream_open((uv_stream_t*)options.stdout_stream, stdout_pipe[0]);
   }
 
@@ -2280,7 +2371,6 @@ int uv_spawn(uv_process_t* process, uv_process_options_t options) {
     assert(stderr_pipe[1] >= 0);
     close(stderr_pipe[1]);
     uv__nonblock(stderr_pipe[0], 1);
-    uv_pipe_init(options.stderr_stream);
     uv__stream_open((uv_stream_t*)options.stderr_stream, stderr_pipe[0]);
   }
 
@@ -2308,3 +2398,125 @@ int uv_process_kill(uv_process_t* process, int signum) {
     return 0;
   }
 }
+
+
+#define LOCKFILE_SUFFIX ".lock"
+int uv_flock_init(uv_flock_t* lock, const char* filename) {
+  int saved_errno;
+  int status;
+  char* lockfile;
+
+  saved_errno = errno;
+  status = -1;
+
+  lock->lockfd = -1;
+  lock->lockfile = NULL;
+
+  if ((lockfile = malloc(strlen(filename) + sizeof LOCKFILE_SUFFIX)) == NULL) {
+    goto out;
+  }
+
+  strcpy(lockfile, filename);
+  strcat(lockfile, LOCKFILE_SUFFIX);
+  lock->lockfile = lockfile;
+  status = 0;
+
+out:
+  errno = saved_errno;
+  return status;
+}
+#undef LOCKFILE_SUFFIX
+
+
+int uv_flock_acquire(uv_flock_t* lock, int* locked_p) {
+  char buf[32];
+  int saved_errno;
+  int status;
+  int lockfd;
+  int locked;
+
+  saved_errno = errno;
+  status = -1;
+  lockfd = -1;
+  locked = 0;
+
+  do {
+    lockfd = open(lock->lockfile, O_WRONLY | O_CREAT, 0666);
+  }
+  while (lockfd == -1 && errno == EINTR);
+
+  if (lockfd == -1) {
+    goto out;
+  }
+
+  do {
+    status = flock(lockfd, LOCK_EX | LOCK_NB);
+  }
+  while (status == -1 && errno == EINTR);
+
+  if (status == -1) {
+    locked = (errno == EAGAIN); /* Lock is held by another process. */
+    goto out;
+  }
+
+  snprintf(buf, sizeof buf, "%d\n", getpid());
+  do {
+    status = write(lockfd, buf, strlen(buf));
+  }
+  while (status == -1 && errno == EINTR);
+
+  lock->lockfd = lockfd;
+  status = 0;
+
+out:
+  if (status) {
+    uv__close(lockfd);
+  }
+
+  if (locked_p) {
+    *locked_p = locked;
+  }
+
+  errno = saved_errno;
+  return status;
+}
+
+
+int uv_flock_release(uv_flock_t* lock) {
+  int saved_errno;
+  int status;
+
+  saved_errno = errno;
+  status = -1;
+
+  if (unlink(lock->lockfile) == -1) {
+    /* Now what? */
+    goto out;
+  }
+
+  uv__close(lock->lockfd);
+  lock->lockfd = -1;
+  status = 0;
+
+out:
+  errno = saved_errno;
+  return status;
+}
+
+
+int uv_flock_destroy(uv_flock_t* lock) {
+  int saved_errno;
+  int status;
+
+  saved_errno = errno;
+  status = unlink(lock->lockfile);
+
+  uv__close(lock->lockfd);
+  lock->lockfd = -1;
+
+  free((void*)lock->lockfile);
+  lock->lockfile = NULL;
+
+  errno = saved_errno;
+  return status;
+}
diff --git a/deps/uv/src/win/pipe.c b/deps/uv/src/win/pipe.c
index 7c98ab0effa..ee627c8879f 100644
--- a/deps/uv/src/win/pipe.c
+++ b/deps/uv/src/win/pipe.c
@@ -444,13 +444,13 @@ int uv_pipe_listen(uv_pipe_t* handle, int backlog, uv_connection_cb cb) {
   HANDLE pipeHandle;
 
   if (handle->flags & UV_HANDLE_BIND_ERROR) {
-    LOOP->last_error = handle->error;
+    uv_set_error(UV_EINVAL, 0);
     return -1;
   }
 
   if (!(handle->flags & UV_HANDLE_BOUND) && 
       !(handle->flags & UV_HANDLE_GIVEN_OS_HANDLE)) {
-    uv_set_error(UV_ENOTCONN, 0);
+    uv_set_error(UV_EINVAL, 0);
     return -1;
   }
 
diff --git a/deps/uv/test/benchmark-pump.c b/deps/uv/test/benchmark-pump.c
index 4e7f1d7ace6..c6cd2d14191 100644
--- a/deps/uv/test/benchmark-pump.c
+++ b/deps/uv/test/benchmark-pump.c
@@ -149,7 +149,6 @@ void read_sockets_close_cb(uv_handle_t* handle) {
 
 
 static void start_stats_collection() {
-  uv_req_t* req = req_alloc();
   int r;
 
   /* Show-stats timer */
@@ -184,8 +183,6 @@ static void read_cb(uv_stream_t* stream, ssize_t bytes, uv_buf_t buf) {
 
 
 static void write_cb(uv_write_t* req, int status) {
-  uv_buf_t* buf = (uv_buf_t*) req->data;
-
   ASSERT(status == 0);
 
   req_free((uv_req_t*) req);
diff --git a/deps/uv/test/test-pipe-bind-error.c b/deps/uv/test/test-pipe-bind-error.c
index 69aaaa20cd4..80c76da8da9 100644
--- a/deps/uv/test/test-pipe-bind-error.c
+++ b/deps/uv/test/test-pipe-bind-error.c
@@ -64,7 +64,7 @@ TEST_IMPL(pipe_bind_error_addrinuse) {
   r = uv_listen((uv_stream_t*)&server2, SOMAXCONN, NULL);
   ASSERT(r == -1);
 
-  ASSERT(uv_last_error().code == UV_EADDRINUSE);
+  ASSERT(uv_last_error().code == UV_EINVAL);
 
   uv_close((uv_handle_t*)&server1, close_cb);
   uv_close((uv_handle_t*)&server2, close_cb);
@@ -136,7 +136,7 @@ TEST_IMPL(pipe_listen_without_bind) {
   r = uv_listen((uv_stream_t*)&server, SOMAXCONN, NULL);
   ASSERT(r == -1);
 
-  ASSERT(uv_last_error().code == UV_ENOTCONN);
+  ASSERT(uv_last_error().code == UV_EINVAL);
 
   uv_close((uv_handle_t*)&server, close_cb);
 
diff --git a/deps/uv/test/test-spawn.c b/deps/uv/test/test-spawn.c
index 9449af7cb92..1ad274ef780 100644
--- a/deps/uv/test/test-spawn.c
+++ b/deps/uv/test/test-spawn.c
@@ -114,6 +114,8 @@ TEST_IMPL(spawn_stdout) {
   uv_init();
 
   init_process_options("spawn_helper2");
+
+  uv_pipe_init(&out);
   options.stdout_stream = &out;
 
   r = uv_spawn(&process, options);