Bug 676053 - export task followed by import task causes cache assertion

https://bugzilla.redhat.com/show_bug.cgi?id=676053

Description: There were 3 places where an entry was not released
by CACHE_RETURN (== not decrementing refcnt).  If an entry has
positive refcnt in the entry cache, it won't be freed even if
the entry never be accessed again.
1. When a search request with VLV and/or SORT control failed.
2. When comparing entries in compare_entries_sv (sort.c), and the
   second entry was not found, the first entry was not released.
3. vlv_trim_candidates_byvalue (vlv.c) retrieves entries for
   performing binary search over the candidate list and put them
   into the cache.  They were not released.

This patch adds CACHE_RETURN call for the above cases.

ldap/servers/slapd/back-ldbm/cache.c

@@ -286,7 +286,6 @@ dump_hash(Hashtable *ht)
     char *p;
     int ids_size = 80;
 
-    LDAPDebug0Args(LDAP_DEBUG_ANY, "entry cache:\n");
     p = ep_ids;
     for (i = 0; i < ht->size; i++) {
         int len;
@@ -301,8 +300,8 @@ dump_hash(Hashtable *ht)
                 LDAPDebug1Arg(LDAP_DEBUG_ANY, "%s\n", ep_ids);
                 p = ep_ids; ids_size = 80;
             }
-            PR_snprintf(p, ids_size, "%s", ep_id);
-            p += len; ids_size -= len + 1;
+            PR_snprintf(p, ids_size, "%s:", ep_id);
+            p += len + 1; ids_size -= len + 1;
         } while (e = HASH_NEXT(ht, e));
     }
     if (p != ep_ids) {
@@ -614,6 +613,7 @@ static void entrycache_clear_int(struct cache *cache)
                      "entrycache_clear_int: there are still %ld entries "
                      "in the entry cache.\n", cache->c_curentries);
 #ifdef LDAP_CACHE_DEBUG
+        LDAPDebug0Args(LDAP_DEBUG_ANY, "ID(s) in entry cache:\n");
         dump_hash(cache->c_idtable);
 #endif
     }

ldap/servers/slapd/back-ldbm/ldbm_search.c

@@ -106,9 +106,24 @@ berval_done(struct berval *val)
 /*
  * We call this function as we exit ldbm_back_search
  */
-int ldbm_back_search_cleanup(Slapi_PBlock *pb, struct ldbminfo *li, sort_spec_thing *sort_control, int ldap_result, char* ldap_result_description, int function_result, Slapi_DN *sdn, struct vlv_request *vlv_request_control)
+static int
+ldbm_back_search_cleanup(Slapi_PBlock *pb,
+                         struct ldbminfo *li,
+                         sort_spec_thing *sort_control,
+                         int ldap_result,
+                         char* ldap_result_description,
+                         int function_result,
+                         Slapi_DN *sdn,
+                         struct vlv_request *vlv_request_control,
+                         struct backentry *e)
 {
     int estimate = 0; /* estimated search result count */
+    backend *be;
+    ldbm_instance *inst;
+
+    slapi_pblock_get( pb, SLAPI_BACKEND, &be );
+    inst = (ldbm_instance *) be->be_instance_info;
+    CACHE_RETURN(&inst->inst_cache, &e); /* NULL e is handled correctly */
 
     if(sort_control!=NULL)
     {
@@ -220,7 +235,10 @@ ldbm_back_search( Slapi_PBlock *pb )
             if(r!=0)
             {
                 /* Badly formed SORT control */
-                return ldbm_back_search_cleanup(pb, li, sort_control, LDAP_PROTOCOL_ERROR, "Sort Control", SLAPI_FAIL_GENERAL, &basesdn, NULL);
+                return ldbm_back_search_cleanup(pb, li, sort_control, 
+                                LDAP_PROTOCOL_ERROR, "Sort Control", 
+                                SLAPI_FAIL_GENERAL, &basesdn, 
+                                NULL, NULL);
             }
             /* set this operation includes the server side sorting */
             operation->o_flags |= OP_FLAG_SERVER_SIDE_SORTING;
@@ -236,7 +254,10 @@ ldbm_back_search( Slapi_PBlock *pb )
                 if(r!=LDAP_SUCCESS)
                 {
                     /* Badly formed VLV control */
-                    return ldbm_back_search_cleanup(pb, li, sort_control, r, "VLV Control", SLAPI_FAIL_GENERAL, &basesdn, &vlv_request_control);
+                    return ldbm_back_search_cleanup(pb, li, sort_control,
+                                r, "VLV Control", 
+                                SLAPI_FAIL_GENERAL, &basesdn, 
+                                &vlv_request_control, NULL);
                 }
                 {
                     /* Access Control Check to see if the client is allowed to use the VLV Control. */
@@ -255,7 +276,10 @@ ldbm_back_search( Slapi_PBlock *pb )
                     if(r!=LDAP_SUCCESS)
                     {
                         /* Client isn't allowed to do this. */
-                        return ldbm_back_search_cleanup(pb, li, sort_control, r, "VLV Control", SLAPI_FAIL_GENERAL, &basesdn, &vlv_request_control);
+                        return ldbm_back_search_cleanup(pb, li, sort_control, 
+                                    r, "VLV Control", 
+                                    SLAPI_FAIL_GENERAL, &basesdn, 
+                                    &vlv_request_control, NULL);
                     }
                 }
                 /*
@@ -267,7 +291,10 @@ ldbm_back_search( Slapi_PBlock *pb )
             else
             {
                 /* Can't have a VLV control without a SORT control */
-                return ldbm_back_search_cleanup(pb, li, sort_control, LDAP_SORT_CONTROL_MISSING, "VLV Control", SLAPI_FAIL_GENERAL, &basesdn, &vlv_request_control);
+                return ldbm_back_search_cleanup(pb, li, sort_control, 
+                                LDAP_SORT_CONTROL_MISSING, "VLV Control", 
+                                SLAPI_FAIL_GENERAL, &basesdn, 
+                                &vlv_request_control, NULL);
             }
         }
     }
@@ -320,13 +347,15 @@ ldbm_back_search( Slapi_PBlock *pb )
             {
                 return ldbm_back_search_cleanup(pb, li, sort_control,
                             LDAP_UNWILLING_TO_PERFORM, ctrlstr,
-                            SLAPI_FAIL_GENERAL, &basesdn, &vlv_request_control);
+                            SLAPI_FAIL_GENERAL, &basesdn, 
+                            &vlv_request_control, NULL);
             }
             else
             {
                 return ldbm_back_search_cleanup(pb, li, sort_control,
                             LDAP_VIRTUAL_LIST_VIEW_ERROR, ctrlstr,
-                            SLAPI_FAIL_GENERAL, &basesdn, &vlv_request_control);
+                            SLAPI_FAIL_GENERAL, &basesdn, 
+                            &vlv_request_control, NULL);
             }
         }
         else
@@ -341,7 +370,8 @@ ldbm_back_search( Slapi_PBlock *pb )
                 sort_make_sort_response_control(pb, LDAP_UNWILLING_TO_PERFORM, NULL);
                 return ldbm_back_search_cleanup(pb, li, sort_control,
                             LDAP_UNAVAILABLE_CRITICAL_EXTENSION, ctrlstr,
-                            SLAPI_FAIL_GENERAL, &basesdn, &vlv_request_control);
+                            SLAPI_FAIL_GENERAL, &basesdn, 
+                            &vlv_request_control, NULL);
             }
             else /* vlv and sorting are not critical, so ignore the control */
             {
@@ -374,7 +404,8 @@ ldbm_back_search( Slapi_PBlock *pb )
         if ( ( e = find_entry( pb, be, addr, NULL )) == NULL )
         {
             /* error or referral sent by find_entry */
-            return ldbm_back_search_cleanup(pb, li, sort_control, -1, NULL, 1, &basesdn, &vlv_request_control);
+            return ldbm_back_search_cleanup(pb, li, sort_control, 
+                            -1, NULL, 1, &basesdn, &vlv_request_control, NULL);
         }
     }
 
@@ -407,12 +438,13 @@ ldbm_back_search( Slapi_PBlock *pb )
                 return ldbm_back_search_cleanup(pb, li, sort_control,
                                                 vlv_rc, "VLV Control",
                                                 SLAPI_FAIL_GENERAL, &basesdn,
-                                                &vlv_request_control);
+                                                &vlv_request_control, e);
             case VLV_BLD_LIST_FAILED:
                 return ldbm_back_search_cleanup(pb, li, sort_control,
                                                 vlv_response_control.result,
                                                 NULL, SLAPI_FAIL_GENERAL,
-                                                &basesdn, &vlv_request_control);
+                                                &basesdn, &vlv_request_control,
+                                                e);
                 
             case LDAP_SUCCESS:
                 /* Log to the access log the particulars of this sort request */
@@ -434,7 +466,7 @@ ldbm_back_search( Slapi_PBlock *pb )
                                                     "Sort Response Control",
                                                     SLAPI_FAIL_GENERAL,
                                                     &basesdn,
-                                                    &vlv_request_control);
+                                                    &vlv_request_control, e);
                 }
             }
         }
@@ -447,7 +479,7 @@ ldbm_back_search( Slapi_PBlock *pb )
                 /* Error result sent by build_candidate_list */
                 return ldbm_back_search_cleanup(pb, li, sort_control, -1,
                                                 NULL, rc, &basesdn,
-                                                &vlv_request_control);
+                                                &vlv_request_control, e);
             }
             /*
              * If we're sorting then we must check what administrative
@@ -491,7 +523,7 @@ ldbm_back_search( Slapi_PBlock *pb )
                 {
                     return ldbm_back_search_cleanup(pb, li, sort_control,
                                                     r, NULL, -1, &basesdn,
-                                                    &vlv_request_control);
+                                                    &vlv_request_control, e);
                 }
             }
             /*
@@ -509,7 +541,7 @@ ldbm_back_search( Slapi_PBlock *pb )
                     return ldbm_back_search_cleanup(pb, li, sort_control,
                                              LDAP_PROTOCOL_ERROR,
                                              "Sort Response Control", -1,
-                                             &basesdn, &vlv_request_control);
+                                             &basesdn, &vlv_request_control, e);
                 }
               }
               else
@@ -551,7 +583,7 @@ ldbm_back_search( Slapi_PBlock *pb )
                                                     LDAP_PROTOCOL_ERROR,
                                                     "Sort Control", -1,
                                                     &basesdn,
-                                                    &vlv_request_control);
+                                                    &vlv_request_control, e);
                 case LDAP_UNWILLING_TO_PERFORM:  /* Too hard */
                 case LDAP_OPERATIONS_ERROR:  /* Operation error */
                 case LDAP_TIMELIMIT_EXCEEDED:  /* Timeout */
@@ -593,7 +625,7 @@ ldbm_back_search( Slapi_PBlock *pb )
                     return ldbm_back_search_cleanup(pb, li, sort_control,
                                              (abandoned?-1:LDAP_PROTOCOL_ERROR),
                                              "Sort Response Control", -1,
-                                             &basesdn, &vlv_request_control);
+                                             &basesdn, &vlv_request_control, e);
                 }
               }
             }
@@ -619,7 +651,7 @@ ldbm_back_search( Slapi_PBlock *pb )
                         return ldbm_back_search_cleanup(pb, li, sort_control,
                                                     vlv_response_control.result,
                                                     NULL, -1, &basesdn,
-                                                    &vlv_request_control);
+                                                    &vlv_request_control, e);
                     }
                 }
                 else
@@ -638,7 +670,7 @@ ldbm_back_search( Slapi_PBlock *pb )
                 return ldbm_back_search_cleanup(pb, li, sort_control,
                                              (abandoned?-1:LDAP_PROTOCOL_ERROR),
                                              "VLV Response Control", -1,
-                                             &basesdn, &vlv_request_control);
+                                             &basesdn, &vlv_request_control, e);
             }
             /* Log the VLV operation */
             vlv_print_access_log(pb,&vlv_request_control,&vlv_response_control);
@@ -702,7 +734,7 @@ ldbm_back_search( Slapi_PBlock *pb )
     /* tmp_err == -1: no error */
     return ldbm_back_search_cleanup(pb, li, sort_control, tmp_err, tmp_desc,
                                     (tmp_err  == -1 ? 0 : -1), &basesdn,
-                                    &vlv_request_control);
+                                    &vlv_request_control, NULL);
     /* end Fix for bugid #394184 */
 }
 

ldap/servers/slapd/back-ldbm/sort.c

@@ -632,6 +632,7 @@ static int compare_entries_sv(ID *id_a, ID *id_b, sort_spec *s,baggage_carrier *
 		if (0 != err ) {
 			LDAPDebug(LDAP_DEBUG_TRACE,"compare_entries db err %d\n",err,0,0);
 		}
+		CACHE_RETURN(&inst->inst_cache,&a);
 		return 0;
 	}
 	/* OK, now we have the entries, so we work our way down the attribute list comparing as we go */

ldap/servers/slapd/back-ldbm/vlv.c

@@ -1634,10 +1634,10 @@ retry:
                 {
                     match= sort_attr_compare((struct berval**)typedown_value, entry_value, compare_fn);
                 }
-        if (needFree) {
-            ber_bvecfree((struct berval**)entry_value);
-            entry_value = NULL;
-        }
+                if (needFree) {
+                    ber_bvecfree((struct berval**)entry_value);
+                    entry_value = NULL;
+                }
             }
             else
             {
@@ -1690,6 +1690,8 @@ retry:
                     LDAPDebug( LDAP_DEBUG_TRACE, "<= vlv_trim_candidates_byvalue: Found. Index %lu\n",si, 0, 0 );
                 }
             }
+            CACHE_RETURN(&(((ldbm_instance *)be->be_instance_info)->inst_cache),
+                         &e);
         }
     } while (!found);
     ber_bvecfree((struct berval**)typedown_value);