osc/rdma: modify attach to check for region overlap

This commit addresses two issues in osc/rdma:

 1) It is erroneous to attach regions that overlap. This was being
    allowed but the standard does not allow overlapping attachments.

 2) Overlapping registration regions (4k alignment of attachments)
    appear to be allowed. Add attachment bases to the bookeeping
    structure so we can keep better track of what can be detached.

It is possible that the standard did not intend to allow #2. If that
is the case then #2 should fail in the same way as #1. There should
be no technical reason to disallow #2 at this time.

References #7384

Signed-off-by: Nathan Hjelm <hjelmn@google.com>

Author: hjelmn

ompi/mca/osc/rdma/osc_rdma.h

@@ -13,6 +13,7 @@
  * Copyright (c) 2010      Cisco Systems, Inc.  All rights reserved.
  * Copyright (c) 2012-2013 Sandia National Laboratories.  All rights reserved.
  * Copyright (c) 2016-2018 Intel, Inc. All rights reserved.
+ * Copyright (c) 2020      Google, LLC. All rights reserved.
  * $COPYRIGHT$
  *
  * Additional copyrights may follow
@@ -250,7 +251,7 @@ struct ompi_osc_rdma_module_t {
 
     /** registration handles for dynamically attached regions. These are not stored
      * in the state structure as it is entirely local. */
-    ompi_osc_rdma_handle_t *dynamic_handles;
+    ompi_osc_rdma_handle_t **dynamic_handles;
 
     /** shared memory segment. this segment holds this node's portion of the rank -> node
      * mapping array, node communication data (node_comm_info), state for all local ranks,

ompi/mca/osc/rdma/osc_rdma_component.c

@@ -21,6 +21,7 @@
  * Copyright (c) 2018      Amazon.com, Inc. or its affiliates.  All Rights reserved.
  * Copyright (c) 2019      Research Organization for Information Science
  *                         and Technology (RIST).  All rights reserved.
+ * Copyright (c) 2020      Google, LLC. All rights reserved.
  * $COPYRIGHT$
  *
  * Additional copyrights may follow
@@ -222,7 +223,7 @@ static int ompi_osc_rdma_component_register (void)
     opal_asprintf(&description_str, "Maximum number of buffers that can be attached to a dynamic window. "
              "Keep in mind that each attached buffer will use a potentially limited "
              "resource (default: %d)", mca_osc_rdma_component.max_attach);
-   (void) mca_base_component_var_register (&mca_osc_rdma_component.super.osc_version, "max_attach", description_str,
+    (void) mca_base_component_var_register (&mca_osc_rdma_component.super.osc_version, "max_attach", description_str,
                                            MCA_BASE_VAR_TYPE_UNSIGNED_INT, NULL, 0, 0, OPAL_INFO_LVL_3,
                                            MCA_BASE_VAR_SCOPE_GROUP, &mca_osc_rdma_component.max_attach);
     free(description_str);
@@ -1267,8 +1268,8 @@ static int ompi_osc_rdma_component_select (struct ompi_win_t *win, void **base,
 
     if (MPI_WIN_FLAVOR_DYNAMIC == flavor) {
         /* allocate space to store local btl handles for attached regions */
-        module->dynamic_handles = (ompi_osc_rdma_handle_t *) calloc (mca_osc_rdma_component.max_attach,
-                                                                     sizeof (module->dynamic_handles[0]));
+        module->dynamic_handles = (ompi_osc_rdma_handle_t **) calloc (mca_osc_rdma_component.max_attach,
+                                                                      sizeof (module->dynamic_handles[0]));
         if (NULL == module->dynamic_handles) {
             ompi_osc_rdma_free (win);
             return OMPI_ERR_OUT_OF_RESOURCE;

ompi/mca/osc/rdma/osc_rdma_dynamic.c

@@ -2,6 +2,7 @@
 /*
  * Copyright (c) 2014-2016 Los Alamos National Security, LLC.  All rights
  *                         reserved.
+ * Copyright (c) 2020      Google, LLC. All rights reserved.
  * $COPYRIGHT$
  *
  * Additional copyrights may follow
@@ -16,6 +17,22 @@
 
 #include "opal/util/sys_limits.h"
 
+static void ompi_osc_rdma_handle_init (ompi_osc_rdma_handle_t *rdma_handle)
+{
+    rdma_handle->btl_handle = NULL;
+    OBJ_CONSTRUCT(&rdma_handle->attachments, opal_list_t);
+}
+
+static void ompi_osc_rdma_handle_fini (ompi_osc_rdma_handle_t *rdma_handle)
+{
+    OPAL_LIST_DESTRUCT(&rdma_handle->attachments);
+}
+
+OBJ_CLASS_INSTANCE(ompi_osc_rdma_handle_t, opal_object_t, ompi_osc_rdma_handle_init,
+                   ompi_osc_rdma_handle_fini);
+
+OBJ_CLASS_INSTANCE(ompi_osc_rdma_attachment_t, opal_list_item_t, NULL, NULL);
+
 /**
  * ompi_osc_rdma_find_region_containing:
  *
@@ -48,13 +65,16 @@ static inline ompi_osc_rdma_region_t *ompi_osc_rdma_find_region_containing (ompi
 
     region_bound = (intptr_t) (region->base + region->len);
 
-    OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_DEBUG, "checking memory region %p-%p against %p-%p (index %d) (min_index = %d, max_index = %d)",
-                         (void *) base, (void *) bound, (void *) region->base, (void *)(region->base + region->len), mid_index,
-                         min_index, max_index);
+    OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_DEBUG, "checking memory region %p-%p against %p-%p (index %d) (min_index = %d, "
+                     "max_index = %d)", (void *) base, (void *) bound, (void *) region->base,
+                     (void *)(region->base + region->len), mid_index, min_index, max_index);
 
     if (region->base > base) {
-        return ompi_osc_rdma_find_region_containing (regions, min_index, mid_index-1, base, bound, region_size, region_index);
-    } else if (bound <= region_bound) {
+        return ompi_osc_rdma_find_region_containing (regions, min_index, mid_index-1, base, bound, region_size,
+                                                     region_index);
+    }
+
+    if (bound <= region_bound) {
         if (region_index) {
             *region_index = mid_index;
         }
@@ -66,24 +86,76 @@ static inline ompi_osc_rdma_region_t *ompi_osc_rdma_find_region_containing (ompi
 }
 
 /* binary search for insertion point */
-static ompi_osc_rdma_region_t *find_insertion_point (ompi_osc_rdma_region_t *regions, int min_index, int max_index, intptr_t base,
-                                                     size_t region_size, int *region_index)
+static ompi_osc_rdma_region_t *find_insertion_point (ompi_osc_rdma_region_t *regions, int min_index, int max_index,
+                                                     intptr_t base, size_t region_size, int *region_index)
 {
     int mid_index = (max_index + min_index) >> 1;
     ompi_osc_rdma_region_t *region = (ompi_osc_rdma_region_t *)((intptr_t) regions + mid_index * region_size);
 
-    OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_TRACE, "find_insertion_point (%d, %d, %lx, %lu)\n", min_index, max_index, base, region_size);
+    OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_TRACE, "find_insertion_point (%d, %d, %lx, %lu)\n", min_index, max_index, base,
+                     region_size);
 
     if (max_index < min_index) {
         *region_index = min_index;
         return (ompi_osc_rdma_region_t *)((intptr_t) regions + min_index * region_size);
     }
 
-    if (region->base > base) {
+    if (region->base > base || (region->base == base && region->len > region_size)) {
         return find_insertion_point (regions, min_index, mid_index-1, base, region_size, region_index);
-    } else {
-        return find_insertion_point (regions, mid_index+1, max_index, base, region_size, region_index);
     }
+
+    return find_insertion_point (regions, mid_index+1, max_index, base, region_size, region_index);
+}
+
+static bool ompi_osc_rdma_find_conflicting_attachment (ompi_osc_rdma_handle_t *handle, intptr_t base, intptr_t bound)
+{
+    ompi_osc_rdma_attachment_t *attachment;
+
+    OPAL_LIST_FOREACH(attachment, &handle->attachments, ompi_osc_rdma_attachment_t) {
+        intptr_t region_bound = attachment->base + attachment->len;
+        if (base >= attachment->base && base < region_bound ||
+            bound > attachment->base && bound <= region_bound) {
+            OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_TRACE, "existing region {%p, %p} overlaps region {%p, %p}",
+                             (void *) attachment->base, (void *) region_bound, (void *) base, (void *) bound);
+            return true;
+        }
+    }
+
+    return false;
+}
+
+static int ompi_osc_rdma_add_attachment (ompi_osc_rdma_handle_t *handle, intptr_t base, size_t len)
+{
+    ompi_osc_rdma_attachment_t *attachment = OBJ_NEW(ompi_osc_rdma_attachment_t);
+    assert (NULL != attachment);
+
+    if (ompi_osc_rdma_find_conflicting_attachment(handle, base, base + len)) {
+        return OMPI_ERR_RMA_ATTACH;
+    }
+
+    attachment->base = base;
+    attachment->len = len;
+
+    opal_list_append (&handle->attachments, &attachment->super);
+
+    return OMPI_SUCCESS;
+}
+
+static int ompi_osc_rdma_remove_attachment (ompi_osc_rdma_handle_t *handle, intptr_t base)
+{
+    ompi_osc_rdma_attachment_t *attachment;
+
+    OPAL_LIST_FOREACH(attachment, &handle->attachments, ompi_osc_rdma_attachment_t) {
+        OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_TRACE, "checking attachment %p against %p",
+                         (void *) attachment->base, (void *) base);
+        if (attachment->base == (intptr_t) base) {
+            opal_list_remove_item (&handle->attachments, &attachment->super);
+            OBJ_RELEASE(attachment);
+            return OMPI_SUCCESS;
+        }
+    }
+
+    return OMPI_ERR_NOT_FOUND;
 }
 
 int ompi_osc_rdma_attach (struct ompi_win_t *win, void *base, size_t len)
@@ -92,12 +164,13 @@ int ompi_osc_rdma_attach (struct ompi_win_t *win, void *base, size_t len)
     const int my_rank = ompi_comm_rank (module->comm);
     ompi_osc_rdma_peer_t *my_peer = ompi_osc_rdma_module_peer (module, my_rank);
     ompi_osc_rdma_region_t *region;
+    ompi_osc_rdma_handle_t *rdma_region_handle;
     osc_rdma_counter_t region_count;
     osc_rdma_counter_t region_id;
-    void *bound;
+    intptr_t bound, aligned_base, aligned_bound;
     intptr_t page_size = opal_getpagesize ();
-    int region_index;
-    int ret;
+    int region_index, ret;
+    size_t aligned_len;
 
     if (module->flavor != MPI_WIN_FLAVOR_DYNAMIC) {
         return OMPI_ERR_RMA_FLAVOR;
@@ -117,23 +190,26 @@ int ompi_osc_rdma_attach (struct ompi_win_t *win, void *base, size_t len)
 
     if (region_count == mca_osc_rdma_component.max_attach) {
         OPAL_THREAD_UNLOCK(&module->lock);
+        OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_TRACE, "attach: could not attach. max attachment count reached.");
         return OMPI_ERR_RMA_ATTACH;
     }
 
     /* it is wasteful to register less than a page. this may allow the remote side to access more
      * memory but the MPI standard covers this with calling the calling behavior erroneous */
-    bound = (void *)OPAL_ALIGN((intptr_t) base + len, page_size, intptr_t);
-    base = (void *)((intptr_t) base & ~(page_size - 1));
-    len = (size_t)((intptr_t) bound - (intptr_t) base);
-
-    /* see if a matching region already exists */
-    region = ompi_osc_rdma_find_region_containing ((ompi_osc_rdma_region_t *) module->state->regions, 0, region_count - 1, (intptr_t) base,
-                                                   (intptr_t) bound, module->region_size, &region_index);
+    bound = (intptr_t) base + len;
+    aligned_bound = OPAL_ALIGN((intptr_t) base + len, page_size, intptr_t);
+    aligned_base = (intptr_t) base & ~(page_size - 1);
+    aligned_len = (size_t)(aligned_bound - aligned_base);
+
+    /* see if a registered region already exists */
+    region = ompi_osc_rdma_find_region_containing ((ompi_osc_rdma_region_t *) module->state->regions, 0, region_count - 1,
+                                                   aligned_base, aligned_bound, module->region_size, &region_index);
     if (NULL != region) {
-        ++module->dynamic_handles[region_index].refcnt;
+        /* validates that the region does not overlap with an existing region even if they are on the same page */
+        ret = ompi_osc_rdma_add_attachment (module->dynamic_handles[region_index], (intptr_t) base, len);
         OPAL_THREAD_UNLOCK(&module->lock);
         /* no need to invalidate remote caches */
-        return OMPI_SUCCESS;
+        return ret;
     }
 
     /* region is in flux */
@@ -144,45 +220,50 @@ int ompi_osc_rdma_attach (struct ompi_win_t *win, void *base, size_t len)
 
     /* do a binary seach for where the region should be inserted */
     if (region_count) {
-        region = find_insertion_point ((ompi_osc_rdma_region_t *) module->state->regions, 0, region_count - 1, (intptr_t) base,
-                                       module->region_size, &region_index);
+        region = find_insertion_point ((ompi_osc_rdma_region_t *) module->state->regions, 0, region_count - 1,
+                                       (intptr_t) base, module->region_size, &region_index);
 
         if (region_index < region_count) {
-            memmove ((void *) ((intptr_t) region + module->region_size), region, (region_count - region_index) * module->region_size);
-
-            if (module->selected_btl->btl_register_mem) {
-                memmove (module->dynamic_handles + region_index + 1, module->dynamic_handles + region_index,
-                         (region_count - region_index) * sizeof (module->dynamic_handles[0]));
-            }
+            memmove ((void *) ((intptr_t) region + module->region_size), region,
+                     (region_count - region_index) * module->region_size);
+            memmove (module->dynamic_handles + region_index + 1, module->dynamic_handles + region_index,
+                     (region_count - region_index) * sizeof (module->dynamic_handles[0]));
         }
     } else {
         region_index = 0;
         region = (ompi_osc_rdma_region_t *) module->state->regions;
     }
 
-    region->base = (intptr_t) base;
-    region->len  = len;
+    region->base = aligned_base;
+    region->len  = aligned_len;
+
+    OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_DEBUG, "attaching dynamic memory region {%p, %p} aligned {%p, %p}, at index %d",
+                     base, (void *) bound, (void *) aligned_base, (void *) aligned_bound, region_index);
 
-    OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_DEBUG, "attaching dynamic memory region {%p, %p} at index %d",
-                     base, (void *)((intptr_t) base + len), region_index);
+    /* add RDMA region handle to track this region */
+    rdma_region_handle = OBJ_NEW(ompi_osc_rdma_handle_t);
+    assert (NULL != rdma_region_handle);
 
     if (module->selected_btl->btl_register_mem) {
         mca_btl_base_registration_handle_t *handle;
 
-        ret = ompi_osc_rdma_register (module, MCA_BTL_ENDPOINT_ANY, (void *) region->base, region->len, MCA_BTL_REG_FLAG_ACCESS_ANY,
-                                      &handle);
+        ret = ompi_osc_rdma_register (module, MCA_BTL_ENDPOINT_ANY, (void *) region->base, region->len,
+                                      MCA_BTL_REG_FLAG_ACCESS_ANY, &handle);
         if (OPAL_UNLIKELY(OMPI_SUCCESS != ret)) {
             OPAL_THREAD_UNLOCK(&module->lock);
+            OBJ_RELEASE(rdma_region_handle);
             return OMPI_ERR_RMA_ATTACH;
         }
 
         memcpy (region->btl_handle_data, handle, module->selected_btl->btl_registration_handle_size);
-        module->dynamic_handles[region_index].btl_handle = handle;
+        rdma_region_handle->btl_handle = handle;
     } else {
-        module->dynamic_handles[region_index].btl_handle = NULL;
+        rdma_region_handle->btl_handle = NULL;
     }
 
-    module->dynamic_handles[region_index].refcnt = 1;
+    assert(OMPI_SUCCESS == ompi_osc_rdma_add_attachment (rdma_region_handle, (intptr_t) base, len));
+
+    module->dynamic_handles[region_index] = rdma_region_handle;
 
 #if OPAL_ENABLE_DEBUG
     for (int i = 0 ; i < region_count + 1 ; ++i) {
@@ -211,34 +292,46 @@ int ompi_osc_rdma_detach (struct ompi_win_t *win, const void *base)
     ompi_osc_rdma_module_t *module = GET_MODULE(win);
     const int my_rank = ompi_comm_rank (module->comm);
     ompi_osc_rdma_peer_dynamic_t *my_peer = (ompi_osc_rdma_peer_dynamic_t *) ompi_osc_rdma_module_peer (module, my_rank);
+    ompi_osc_rdma_handle_t *rdma_region_handle;
     osc_rdma_counter_t region_count, region_id;
     ompi_osc_rdma_region_t *region;
-    int region_index;
+    void *bound;
+    int start_index = INT_MAX, region_index;
 
     if (module->flavor != MPI_WIN_FLAVOR_DYNAMIC) {
         return OMPI_ERR_WIN;
     }
 
     OPAL_THREAD_LOCK(&module->lock);
 
-    OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_TRACE, "detach: %s, %p", win->w_name, base);
-
     /* the upper 4 bytes of the region count are an instance counter */
     region_count = module->state->region_count & 0xffffffffL;
     region_id    = module->state->region_count >> 32;
 
-    region = ompi_osc_rdma_find_region_containing ((ompi_osc_rdma_region_t *) module->state->regions, 0,
-                                                   region_count - 1, (intptr_t) base, (intptr_t) base + 1,
-                                                   module->region_size, &region_index);
-    if (NULL == region) {
-        OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_INFO, "could not find dynamic memory region starting at %p", base);
-        OPAL_THREAD_UNLOCK(&module->lock);
-        return OMPI_ERROR;
+    /* look up the associated region */
+    for (region_index = 0 ; region_index < region_count ; ++region_index) {
+        rdma_region_handle = module->dynamic_handles[region_index];
+        region = (ompi_osc_rdma_region_t *) ((intptr_t) module->state->regions + region_index * module->region_size);
+        OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_INFO, "checking attachments at index %d {.base=%p, len=%lu} for attachment %p"
+                         ", region handle=%p", region_index, (void *) region->base, region->len, base, rdma_region_handle);
+
+        if (region->base > (uintptr_t) base || (region->base + region->len) < (uintptr_t) base) {
+            continue;
+        }
+
+        if (OPAL_SUCCESS == ompi_osc_rdma_remove_attachment (rdma_region_handle, (intptr_t) base)) {
+            break;
+        }
     }
 
-    if (--module->dynamic_handles[region_index].refcnt > 0) {
+    if (region_index == region_count) {
+        OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_INFO, "could not find dynamic memory attachment for %p", base);
         OPAL_THREAD_UNLOCK(&module->lock);
-        OSC_RDMA_VERBOSE(MCA_BASE_VERBOSE_TRACE, "detach complete");
+        return OMPI_ERR_BASE;
+    }
+
+    if (!opal_list_is_empty (&rdma_region_handle->attachments)) {
+        /* another region is referencing this attachment */
         return OMPI_SUCCESS;
     }
 
@@ -249,21 +342,21 @@ int ompi_osc_rdma_detach (struct ompi_win_t *win, const void *base)
                      base, (void *)((intptr_t) base + region->len), region_index);
 
     if (module->selected_btl->btl_register_mem) {
-        ompi_osc_rdma_deregister (module, module->dynamic_handles[region_index].btl_handle);
+        ompi_osc_rdma_deregister (module, rdma_region_handle->btl_handle);
 
-        if (region_index < region_count - 1) {
-            memmove (module->dynamic_handles + region_index, module->dynamic_handles + region_index + 1,
-                     (region_count - region_index - 1) * sizeof (void *));
-        }
-
-        memset (module->dynamic_handles + region_count - 1, 0, sizeof (module->dynamic_handles[0]));
     }
 
     if (region_index < region_count - 1) {
+        size_t end_count = region_count - region_index - 1;
+        memmove (module->dynamic_handles + region_index, module->dynamic_handles + region_index + 1,
+                 end_count * sizeof (module->dynamic_handles[0]));
         memmove (region, (void *)((intptr_t) region + module->region_size),
-                 (region_count - region_index - 1) * module->region_size);;
+                 end_count * module->region_size);
     }
 
+    OBJ_RELEASE(rdma_region_handle);
+    module->dynamic_handles[region_count - 1] = NULL;
+
     module->state->region_count = ((region_id + 1) << 32) | (region_count - 1);
 
     ompi_osc_rdma_lock_release_exclusive (module, &my_peer->super, offsetof (ompi_osc_rdma_state_t, regions_lock));