diff --git a/deps/uvwasi/include/uvwasi.h b/deps/uvwasi/include/uvwasi.h
index 752c3ba3958e7c..7dbcc667793a07 100644
--- a/deps/uvwasi/include/uvwasi.h
+++ b/deps/uvwasi/include/uvwasi.h
@@ -11,7 +11,7 @@ extern "C" {
 
 #define UVWASI_VERSION_MAJOR 0
 #define UVWASI_VERSION_MINOR 0
-#define UVWASI_VERSION_PATCH 20
+#define UVWASI_VERSION_PATCH 21
 #define UVWASI_VERSION_HEX ((UVWASI_VERSION_MAJOR << 16) | \
                             (UVWASI_VERSION_MINOR <<  8) | \
                             (UVWASI_VERSION_PATCH))
diff --git a/deps/uvwasi/src/path_resolver.c b/deps/uvwasi/src/path_resolver.c
index ec8946b1393d74..deb3f603821f92 100644
--- a/deps/uvwasi/src/path_resolver.c
+++ b/deps/uvwasi/src/path_resolver.c
@@ -269,7 +269,7 @@ static uvwasi_errno_t uvwasi__normalize_relative_path(
      normalized. */
   uvwasi_errno_t err;
   char* combined;
-  char* normalized;
+  char* normalized = NULL;
   uvwasi_size_t combined_len;
   uvwasi_size_t fd_path_len;
   uvwasi_size_t norm_len;
diff --git a/deps/uvwasi/src/uvwasi.c b/deps/uvwasi/src/uvwasi.c
index 40162f886fa224..948c1355c9ccf7 100644
--- a/deps/uvwasi/src/uvwasi.c
+++ b/deps/uvwasi/src/uvwasi.c
@@ -1158,7 +1158,7 @@ uvwasi_errno_t uvwasi_fd_pread(uvwasi_t* uvwasi,
                offset,
                nread);
 
-  if (uvwasi == NULL || iovs == NULL || nread == NULL)
+  if (uvwasi == NULL || (iovs == NULL && iovs_len > 0) || nread == NULL || offset > INT64_MAX)
     return UVWASI_EINVAL;
 
   err = uvwasi_fd_table_get(uvwasi->fds,
@@ -1169,6 +1169,14 @@ uvwasi_errno_t uvwasi_fd_pread(uvwasi_t* uvwasi,
   if (err != UVWASI_ESUCCESS)
     return err;
 
+  // libuv returns EINVAL in this case.  To behave consistently with other
+  // Wasm runtimes, return OK here with a no-op.
+  if (iovs_len == 0) {
+    uv_mutex_unlock(&wrap->mutex);
+    *nread = 0;
+    return UVWASI_ESUCCESS;
+  }
+
   err = uvwasi__setup_iovs(uvwasi, &bufs, iovs, iovs_len);
   if (err != UVWASI_ESUCCESS) {
     uv_mutex_unlock(&wrap->mutex);
@@ -1282,7 +1290,7 @@ uvwasi_errno_t uvwasi_fd_pwrite(uvwasi_t* uvwasi,
                offset,
                nwritten);
 
-  if (uvwasi == NULL || iovs == NULL || nwritten == NULL)
+  if (uvwasi == NULL || (iovs == NULL && iovs_len > 0) || nwritten == NULL || offset > INT64_MAX)
     return UVWASI_EINVAL;
 
   err = uvwasi_fd_table_get(uvwasi->fds,
@@ -1293,6 +1301,14 @@ uvwasi_errno_t uvwasi_fd_pwrite(uvwasi_t* uvwasi,
   if (err != UVWASI_ESUCCESS)
     return err;
 
+  // libuv returns EINVAL in this case.  To behave consistently with other
+  // Wasm runtimes, return OK here with a no-op.
+  if (iovs_len == 0) {
+    uv_mutex_unlock(&wrap->mutex);
+    *nwritten = 0;
+    return UVWASI_ESUCCESS;
+  }
+
   err = uvwasi__setup_ciovs(uvwasi, &bufs, iovs, iovs_len);
   if (err != UVWASI_ESUCCESS) {
     uv_mutex_unlock(&wrap->mutex);
@@ -1332,14 +1348,21 @@ uvwasi_errno_t uvwasi_fd_read(uvwasi_t* uvwasi,
                iovs,
                iovs_len,
                nread);
-
-  if (uvwasi == NULL || iovs == NULL || nread == NULL)
+  if (uvwasi == NULL || (iovs == NULL && iovs_len > 0) || nread == NULL)
     return UVWASI_EINVAL;
 
   err = uvwasi_fd_table_get(uvwasi->fds, fd, &wrap, UVWASI_RIGHT_FD_READ, 0);
   if (err != UVWASI_ESUCCESS)
     return err;
 
+  // libuv returns EINVAL in this case.  To behave consistently with other
+  // Wasm runtimes, return OK here with a no-op.
+  if (iovs_len == 0) {
+    uv_mutex_unlock(&wrap->mutex);
+    *nread = 0;
+    return UVWASI_ESUCCESS;
+  }
+
   err = uvwasi__setup_iovs(uvwasi, &bufs, iovs, iovs_len);
   if (err != UVWASI_ESUCCESS) {
     uv_mutex_unlock(&wrap->mutex);
@@ -1634,13 +1657,21 @@ uvwasi_errno_t uvwasi_fd_write(uvwasi_t* uvwasi,
                iovs_len,
                nwritten);
 
-  if (uvwasi == NULL || iovs == NULL || nwritten == NULL)
+  if (uvwasi == NULL || (iovs == NULL && iovs_len > 0) || nwritten == NULL)
     return UVWASI_EINVAL;
 
   err = uvwasi_fd_table_get(uvwasi->fds, fd, &wrap, UVWASI_RIGHT_FD_WRITE, 0);
   if (err != UVWASI_ESUCCESS)
     return err;
 
+  // libuv returns EINVAL in this case.  To behave consistently with other
+  // Wasm runtimes, return OK here with a no-op.
+  if (iovs_len == 0) {
+    uv_mutex_unlock(&wrap->mutex);
+    *nwritten = 0;
+    return UVWASI_ESUCCESS;
+  }
+
   err = uvwasi__setup_ciovs(uvwasi, &bufs, iovs, iovs_len);
   if (err != UVWASI_ESUCCESS) {
     uv_mutex_unlock(&wrap->mutex);
@@ -2168,7 +2199,7 @@ uvwasi_errno_t uvwasi_path_readlink(uvwasi_t* uvwasi,
 
   memcpy(buf, req.ptr, len);
   buf[len] = '\0';
-  *bufused = len + 1;
+  *bufused = len;
   uv_fs_req_cleanup(&req);
   return UVWASI_ESUCCESS;
 }
diff --git a/test/wasi/c/create_symlink.c b/test/wasi/c/create_symlink.c
index 319b10c6909781..bf9d804753c1dc 100644
--- a/test/wasi/c/create_symlink.c
+++ b/test/wasi/c/create_symlink.c
@@ -11,7 +11,7 @@ int main() {
 
   assert(0 == symlink(target, linkpath));
   assert(readlink(linkpath, readlink_result, result_size) ==
-         strlen(target) + 1);
+         strlen(target));
   assert(0 == strcmp(readlink_result, target));
 
   FILE* file = fopen(linkpath, "r");
diff --git a/test/wasi/wasm/create_symlink.wasm b/test/wasi/wasm/create_symlink.wasm
index 64e120cd5a617b..be824359be6372 100755
Binary files a/test/wasi/wasm/create_symlink.wasm and b/test/wasi/wasm/create_symlink.wasm differ