diff --git a/ompi/mca/common/ompio/common_ompio_buffer.h b/ompi/mca/common/ompio/common_ompio_buffer.h
index 1d1d89eb42e..3a968ded346 100644
--- a/ompi/mca/common/ompio/common_ompio_buffer.h
+++ b/ompi/mca/common/ompio/common_ompio_buffer.h
@@ -29,6 +29,7 @@
     _tbuf = mca_common_ompio_alloc_buf (_fh, _tmp_buf_size==0 ? _max_data : _tmp_buf_size); \
     if ( NULL == _tbuf ) {                                              \
         opal_output(1, "common_ompio: error allocating memory\n");      \
+        opal_convertor_cleanup (_convertor);                            \
         return OMPI_ERR_OUT_OF_RESOURCE;                                \
     }                                                                   \
     if (NULL != _decoded_iov) {                                         \
@@ -43,6 +44,7 @@
     _tbuf = mca_common_ompio_alloc_buf (_fh, _tmp_buf_size==0 ? _max_data : _tmp_buf_size); \
     if ( NULL == _tbuf ) {                                              \
         opal_output(1, "common_ompio: error allocating memory\n");      \
+        opal_convertor_cleanup (_convertor);                            \
         return OMPI_ERR_OUT_OF_RESOURCE;                                \
     }                                                                   \
     if (NULL != _decoded_iov) {                                         \
diff --git a/ompi/mca/common/ompio/common_ompio_file_read.c b/ompi/mca/common/ompio/common_ompio_file_read.c
index 15a62f455c1..7dd180d2df5 100644
--- a/ompi/mca/common/ompio/common_ompio_file_read.c
+++ b/ompi/mca/common/ompio/common_ompio_file_read.c
@@ -205,6 +205,7 @@ int mca_common_ompio_file_read_pipelined (ompio_file_t *fh, void *buf,
         tbuf2 = mca_common_ompio_alloc_buf (fh, bytes_per_cycle);
         if (NULL == tbuf2) {
             opal_output(1, "common_ompio: error allocating memory\n");
+            opal_convertor_cleanup (&convertor);
             return OMPI_ERR_OUT_OF_RESOURCE;
         }
         unpackbuf = tbuf2;
diff --git a/ompi/mca/fbtl/posix/fbtl_posix_ipreadv.c b/ompi/mca/fbtl/posix/fbtl_posix_ipreadv.c
index 7b2ab311b91..3a31d33fbe4 100644
--- a/ompi/mca/fbtl/posix/fbtl_posix_ipreadv.c
+++ b/ompi/mca/fbtl/posix/fbtl_posix_ipreadv.c
@@ -56,8 +56,8 @@ ssize_t mca_fbtl_posix_ipreadv (ompio_file_t *fh,
     data->prd_req_type  = FBTL_POSIX_AIO_READ;
     data->prd_req_chunks = ompi_fbtl_posix_max_prd_active_reqs;
     data->prd_total_len = 0;
-    data->prd_aio.aio_reqs = (struct aiocb *) malloc (sizeof(struct aiocb) *
-                                              fh->f_num_of_io_entries);
+    data->prd_aio.aio_reqs = (struct aiocb *) calloc (fh->f_num_of_io_entries,
+                                                      sizeof(struct aiocb));
     if (NULL == data->prd_aio.aio_reqs) {
         opal_output(1, "mca_fbtl_posix_ipreadv: could not allocate memory\n");
         free(data);
diff --git a/ompi/mca/fbtl/posix/fbtl_posix_ipwritev.c b/ompi/mca/fbtl/posix/fbtl_posix_ipwritev.c
index 49ef459cf18..272c717ed00 100644
--- a/ompi/mca/fbtl/posix/fbtl_posix_ipwritev.c
+++ b/ompi/mca/fbtl/posix/fbtl_posix_ipwritev.c
@@ -55,8 +55,8 @@ ssize_t  mca_fbtl_posix_ipwritev (ompio_file_t *fh,
     data->prd_req_type  = FBTL_POSIX_AIO_WRITE;
     data->prd_req_chunks = ompi_fbtl_posix_max_prd_active_reqs;
     data->prd_total_len = 0;
-    data->prd_aio.aio_reqs = (struct aiocb *) malloc (sizeof(struct aiocb) *
-                                              fh->f_num_of_io_entries);
+    data->prd_aio.aio_reqs = (struct aiocb *) calloc (fh->f_num_of_io_entries,
+                                                      sizeof(struct aiocb));
     if (NULL == data->prd_aio.aio_reqs) {
         opal_output (1,"mca_fbtl_posix_ipwritev: could not allocate memory\n");
         free(data);
diff --git a/ompi/mca/io/ompio/io_ompio_file_open.c b/ompi/mca/io/ompio/io_ompio_file_open.c
index 30b3052295c..76e4eb6c497 100644
--- a/ompi/mca/io/ompio/io_ompio_file_open.c
+++ b/ompi/mca/io/ompio/io_ompio_file_open.c
@@ -427,6 +427,7 @@ static void mca_io_ompio_file_get_eof_offset (ompio_file_t *fh,
         }
         
         offset = prev_offset;
+        assert(index_in_file_view > 0);
         blocklen = fh->f_fview.f_decoded_iov[index_in_file_view-1].iov_len;
         while (offset <= in_offset && k <= blocklen)  {
             prev_offset = offset;
diff --git a/ompi/mca/io/ompio/io_ompio_file_read.c b/ompi/mca/io/ompio/io_ompio_file_read.c
index 8f0583bb0b3..39a11965711 100644
--- a/ompi/mca/io/ompio/io_ompio_file_read.c
+++ b/ompi/mca/io/ompio/io_ompio_file_read.c
@@ -362,13 +362,18 @@ int mca_io_ompio_file_read_all_begin (ompi_file_t *fh,
 
     data = (mca_common_ompio_data_t *) fh->f_io_selected_data;
     fp = &data->ompio_fh;
-    if ( true == fp->f_split_coll_in_use ) {
-	printf("Only one split collective I/O operation allowed per file handle at any given point in time!\n");
-	return MPI_ERR_OTHER;
+
+    OPAL_THREAD_LOCK(&fh->f_lock);
+    if (true == fp->f_split_coll_in_use) {
+        printf("Only one split collective I/O operation allowed per file handle at any given point in time!\n");
+        OPAL_THREAD_UNLOCK(&fh->f_lock);
+        return MPI_ERR_OTHER;
     }
-    /* No need for locking fh->f_lock, that is done in file_iread_all */
-    ret = mca_io_ompio_file_iread_all ( fh, buf, count, datatype, &fp->f_split_coll_req );
     fp->f_split_coll_in_use = true;
+    OPAL_THREAD_UNLOCK(&fh->f_lock);
+
+    /* No need for locking fh->f_lock for the operation itself, that is done in io_ompio_file_iread_all */
+    ret = mca_io_ompio_file_iread_all ( fh, buf, count, datatype, &fp->f_split_coll_req );
 
     return ret;
 }
@@ -402,14 +407,17 @@ int mca_io_ompio_file_read_at_all_begin (ompi_file_t *fh,
     data = (mca_common_ompio_data_t *) fh->f_io_selected_data;
     fp = &data->ompio_fh;
 
-    if ( true == fp->f_split_coll_in_use ) {
-	printf("Only one split collective I/O operation allowed per file handle at any given point in time!\n");
-	return MPI_ERR_REQUEST;
-    }
     OPAL_THREAD_LOCK(&fh->f_lock);
+    if (true == fp->f_split_coll_in_use) {
+        printf("Only one split collective I/O operation allowed per file handle at any given point in time!\n");
+        OPAL_THREAD_UNLOCK(&fh->f_lock);
+        return MPI_ERR_OTHER;
+    }
+
+    fp->f_split_coll_in_use = true;
     ret = mca_common_ompio_file_iread_at_all ( fp, offset, buf, count, datatype, &fp->f_split_coll_req );
     OPAL_THREAD_UNLOCK(&fh->f_lock);
-    fp->f_split_coll_in_use = true;
+
     return ret;
 }
 
diff --git a/ompi/mca/io/ompio/io_ompio_file_write.c b/ompi/mca/io/ompio/io_ompio_file_write.c
index b8609b34771..8efa2a5a3ec 100644
--- a/ompi/mca/io/ompio/io_ompio_file_write.c
+++ b/ompi/mca/io/ompio/io_ompio_file_write.c
@@ -370,13 +370,18 @@ int mca_io_ompio_file_write_all_begin (ompi_file_t *fh,
 
     data = (mca_common_ompio_data_t *) fh->f_io_selected_data;
     fp = &data->ompio_fh;
-    if ( true == fp->f_split_coll_in_use ) {
-	printf("Only one split collective I/O operation allowed per file handle at any given point in time!\n");
-	return MPI_ERR_OTHER;
+
+    OPAL_THREAD_LOCK(&fh->f_lock);
+    if (true == fp->f_split_coll_in_use) {
+        printf("Only one split collective I/O operation allowed per file handle at any given point in time!\n");
+        OPAL_THREAD_UNLOCK(&fh->f_lock);
+        return MPI_ERR_OTHER;
     }
-    /* No need for locking fh->f_lock, that is done in file_iwrite_all */
-    ret = mca_io_ompio_file_iwrite_all ( fh, buf, count, datatype, &fp->f_split_coll_req );
     fp->f_split_coll_in_use = true;
+    OPAL_THREAD_UNLOCK(&fh->f_lock);
+
+    /* No need for locking fh->f_lock the operation itself, that is done in io_ompio_file_iwrite_all */
+    ret = mca_io_ompio_file_iwrite_all ( fh, buf, count, datatype, &fp->f_split_coll_req );
 
     return ret;
 }
@@ -412,14 +417,15 @@ int mca_io_ompio_file_write_at_all_begin (ompi_file_t *fh,
     data = (mca_common_ompio_data_t *) fh->f_io_selected_data;
     fp = &data->ompio_fh;
 
-    if ( true == fp->f_split_coll_in_use ) {
-	printf("Only one split collective I/O operation allowed per file handle at any given point in time!\n");
-	return MPI_ERR_REQUEST;
-    }
     OPAL_THREAD_LOCK(&fh->f_lock);
+    if (true == fp->f_split_coll_in_use) {
+        printf("Only one split collective I/O operation allowed per file handle at any given point in time!\n");
+        OPAL_THREAD_UNLOCK(&fh->f_lock);
+        return MPI_ERR_OTHER;
+    }
+    fp->f_split_coll_in_use = true;
     ret = mca_common_ompio_file_iwrite_at_all ( fp, offset, buf, count, datatype, &fp->f_split_coll_req );
     OPAL_THREAD_UNLOCK(&fh->f_lock);
-    fp->f_split_coll_in_use = true;
 
     return ret;
 }