fix idl lru deletion of last entry (ITS#5121)

diff --git a/servers/slapd/back-bdb/idl.c b/servers/slapd/back-bdb/idl.c
index 35d6d4890d4d228f5fb6f51a262e6621b7997f79..044f2a0d4cee1d9b78421a7d687cd7efd86f0261 100644 (file)
--- a/servers/slapd/back-bdb/idl.c
+++ b/servers/slapd/back-bdb/idl.c
@@ -27,11 +27,24 @@
 
 #define IDL_CMP(x,y)   ( x < y ? -1 : ( x > y ? 1 : 0 ) )
 
-#define IDL_LRU_DELETE( bdb, e ) do {                                  \
-       if ( e == bdb->bi_idl_lru_head ) bdb->bi_idl_lru_head = e->idl_lru_next; \
-       if ( e == bdb->bi_idl_lru_tail ) bdb->bi_idl_lru_tail = e->idl_lru_prev; \
-       e->idl_lru_next->idl_lru_prev = e->idl_lru_prev; \
-       e->idl_lru_prev->idl_lru_next = e->idl_lru_next; \
+#define IDL_LRU_DELETE( bdb, e ) do { \
+       if ( (e) == (bdb)->bi_idl_lru_head ) { \
+               if ( (e)->idl_lru_next == (bdb)->bi_idl_lru_head ) { \
+                       (bdb)->bi_idl_lru_head = NULL; \
+               } else { \
+                       (bdb)->bi_idl_lru_head = (e)->idl_lru_next; \
+               } \
+       } \
+       if ( (e) == (bdb)->bi_idl_lru_tail ) { \
+               if ( (e)->idl_lru_prev == (bdb)->bi_idl_lru_tail ) { \
+                       assert( (bdb)->bi_idl_lru_head == NULL ); \
+                       (bdb)->bi_idl_lru_tail = NULL; \
+               } else { \
+                       (bdb)->bi_idl_lru_tail = (e)->idl_lru_prev; \
+               } \
+       } \
+       (e)->idl_lru_next->idl_lru_prev = (e)->idl_lru_prev; \
+       (e)->idl_lru_prev->idl_lru_next = (e)->idl_lru_next; \
 } while ( 0 )
 
 static int
@@ -349,6 +362,10 @@ bdb_idl_cache_put(
        ldap_pvt_thread_mutex_lock( &bdb->bi_idl_tree_lrulock );
        /* LRU_ADD */
        if ( bdb->bi_idl_lru_head ) {
+               assert( bdb->bi_idl_lru_tail != NULL );
+               assert( bdb->bi_idl_lru_head->idl_lru_prev != NULL );
+               assert( bdb->bi_idl_lru_head->idl_lru_next != NULL );
+
                ee->idl_lru_next = bdb->bi_idl_lru_head;
                ee->idl_lru_prev = bdb->bi_idl_lru_head->idl_lru_prev;
                bdb->bi_idl_lru_head->idl_lru_prev->idl_lru_next = ee;
@@ -364,6 +381,9 @@ bdb_idl_cache_put(
                ee = bdb->bi_idl_lru_tail;
                for ( i = 0; i < 10; i++, ee = eprev ) {
                        eprev = ee->idl_lru_prev;
+                       if ( eprev == ee ) {
+                               eprev = NULL;
+                       }
                        if ( ee->idl_flags & CACHE_ENTRY_REFERENCED ) {
                                ee->idl_flags ^= CACHE_ENTRY_REFERENCED;
                                continue;
@@ -382,6 +402,8 @@ bdb_idl_cache_put(
                        ch_free( ee );
                }
                bdb->bi_idl_lru_tail = eprev;
+               assert( bdb->bi_idl_lru_tail != NULL
+                       || bdb->bi_idl_lru_head == NULL );
        }
        ldap_pvt_thread_mutex_unlock( &bdb->bi_idl_tree_lrulock );
        ldap_pvt_thread_rdwr_wunlock( &bdb->bi_idl_tree_rwlock );