diff --git a/ompi/mca/btl/sm/btl_sm.c b/ompi/mca/btl/sm/btl_sm.c
index 0adff49cf9..30adbac113 100644
--- a/ompi/mca/btl/sm/btl_sm.c
+++ b/ompi/mca/btl/sm/btl_sm.c
@@ -227,11 +227,6 @@ static int sm_btl_first_time_init(mca_btl_sm_t *sm_btl, int n)
     mca_btl_sm_component.sm_mpool_base =
         mca_btl_sm_component.sm_mpools[0]->mpool_base(mca_btl_sm_component.sm_mpools[0]);
 
-    /* set the shared memory offset */
-    mca_btl_sm_component.sm_offset = (ptrdiff_t*)calloc(n, sizeof(ptrdiff_t));
-    if(NULL == mca_btl_sm_component.sm_offset)
-        return OMPI_ERR_OUT_OF_RESOURCE;
-
     /* create a list of peers */
     mca_btl_sm_component.sm_peers = (struct mca_btl_base_endpoint_t**)
         calloc(n, sizeof(struct mca_btl_base_endpoint_t*));
@@ -277,7 +272,7 @@ static int sm_btl_first_time_init(mca_btl_sm_t *sm_btl, int n)
         return OMPI_ERROR;
     }
 
-    mca_btl_sm_component.shm_fifo = (sm_fifo_t **)mca_btl_sm_component.mmap_file->data_addr;
+    mca_btl_sm_component.shm_fifo = (volatile sm_fifo_t **)mca_btl_sm_component.mmap_file->data_addr;
     mca_btl_sm_component.shm_bases = (char**)(mca_btl_sm_component.shm_fifo + n);
     mca_btl_sm_component.shm_mem_nodes = (uint16_t*)(mca_btl_sm_component.shm_bases + n);
 
@@ -293,8 +288,6 @@ static int sm_btl_first_time_init(mca_btl_sm_t *sm_btl, int n)
 
     mca_btl_sm_component.shm_fifo[mca_btl_sm_component.my_smp_rank] = my_fifos;
 
-    opal_atomic_wmb();
-
     /* cache the pointer to the 2d fifo array.  These addresses
      * are valid in the current process space */
     mca_btl_sm_component.fifo = (sm_fifo_t**)malloc(sizeof(sm_fifo_t*) * n);
@@ -499,14 +492,16 @@ int mca_btl_sm_add_procs(
             goto CLEANUP;
     }
 
+    opal_atomic_wmb();
+
     /* Sync with other local procs. Force the FIFO initialization to always
      * happens before the readers access it.
      */
     opal_atomic_add_32( &mca_btl_sm_component.mmap_file->map_seg->seg_inited, 1);
     while( n_local_procs >
            mca_btl_sm_component.mmap_file->map_seg->seg_inited) {
-        opal_atomic_rmb();
         opal_progress();
+        opal_atomic_rmb();
     }
 
     /* coordinate with other processes */
@@ -516,14 +511,14 @@ int mca_btl_sm_add_procs(
 
         /* spin until this element is allocated */
         /* doesn't really wait for that process... FIFO might be allocated, but not initialized */
+        opal_atomic_rmb();
         while(NULL == mca_btl_sm_component.shm_fifo[j]) {
-            opal_atomic_rmb();
             opal_progress();
+            opal_atomic_rmb();
         }
 
         /* Calculate the difference as (my_base - their_base) */
         diff = ADDR2OFFSET(bases[my_smp_rank], bases[j]);
-        mca_btl_sm_component.sm_offset[j] = diff;
 
         /* store local address of remote fifos */
         mca_btl_sm_component.fifo[j] =
diff --git a/ompi/mca/btl/sm/btl_sm.h b/ompi/mca/btl/sm/btl_sm.h
index ddf4ef44f5..c4e101f907 100644
--- a/ompi/mca/btl/sm/btl_sm.h
+++ b/ompi/mca/btl/sm/btl_sm.h
@@ -134,7 +134,7 @@ struct mca_btl_sm_component_t {
     mca_common_sm_mmap_t *mmap_file;   /**< description of mmap'ed file */
     mca_common_sm_file_header_t *sm_ctl_header;  /* control header in
                                                     shared memory */
-    sm_fifo_t **shm_fifo;              /**< pointer to fifo 2D array in shared memory */
+    volatile sm_fifo_t **shm_fifo;     /**< pointer to fifo 2D array in shared memory */
     char **shm_bases;                  /**< pointer to base pointers in shared memory */
     uint16_t *shm_mem_nodes;           /**< pointer to mem noded in shared memory */
     sm_fifo_t **fifo;                  /**< cached copy of the pointer to the 2D
@@ -146,8 +146,6 @@ struct mca_btl_sm_component_t {
     size_t fifo_size;                  /**< number of FIFO queue entries */
     size_t fifo_lazy_free;             /**< number of reads before lazy fifo free is triggered */
     int nfifos;                        /**< number of FIFOs per receiver */
-    ptrdiff_t *sm_offset;              /**< offset to be applied to shared memory
-                                          addresses, per local process value */
     int32_t num_smp_procs;             /**< current number of smp procs on this host */
     int32_t my_smp_rank;               /**< My SMP process rank.  Used for accessing
                                         *   SMP specfic data structures. */