diff --git a/nscd/connections.c b/nscd/connections.c
index e3a6738..597e1a7 100644
--- nscd/connections.c
+++ nscd/connections.c
@@ -109,6 +109,7 @@ struct database_dyn dbs[lastdb] =
   [pwddb] = {
     .lock = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP,
     .prune_lock = PTHREAD_MUTEX_INITIALIZER,
+    .prune_run_lock = PTHREAD_MUTEX_INITIALIZER,
     .enabled = 0,
     .check_file = 1,
     .persistent = 0,
@@ -129,6 +130,7 @@ struct database_dyn dbs[lastdb] =
   [grpdb] = {
     .lock = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP,
     .prune_lock = PTHREAD_MUTEX_INITIALIZER,
+    .prune_run_lock = PTHREAD_MUTEX_INITIALIZER,
     .enabled = 0,
     .check_file = 1,
     .persistent = 0,
@@ -149,6 +151,7 @@ struct database_dyn dbs[lastdb] =
   [hstdb] = {
     .lock = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP,
     .prune_lock = PTHREAD_MUTEX_INITIALIZER,
+    .prune_run_lock = PTHREAD_MUTEX_INITIALIZER,
     .enabled = 0,
     .check_file = 1,
     .persistent = 0,
@@ -169,6 +172,7 @@ struct database_dyn dbs[lastdb] =
   [servdb] = {
     .lock = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP,
     .prune_lock = PTHREAD_MUTEX_INITIALIZER,
+    .prune_run_lock = PTHREAD_MUTEX_INITIALIZER,
     .enabled = 0,
     .check_file = 1,
     .persistent = 0,
@@ -975,9 +979,9 @@ invalidate_cache (char *key, int fd)
 
   if (dbs[number].enabled)
     {
-      pthread_mutex_lock (&dbs[number].prune_lock);
+      pthread_mutex_lock (&dbs[number].prune_run_lock);
       prune_cache (&dbs[number], LONG_MAX, fd);
-      pthread_mutex_unlock (&dbs[number].prune_lock);
+      pthread_mutex_unlock (&dbs[number].prune_run_lock);
     }
   else
     {
@@ -1492,6 +1496,7 @@ nscd_run_prune (void *p)
   dbs[my_number].wakeup_time = now + CACHE_PRUNE_INTERVAL + my_number;
 
   pthread_mutex_t *prune_lock = &dbs[my_number].prune_lock;
+  pthread_mutex_t *prune_run_lock = &dbs[my_number].prune_run_lock;
   pthread_cond_t *prune_cond = &dbs[my_number].prune_cond;
 
   pthread_mutex_lock (prune_lock);
@@ -1523,7 +1528,10 @@ nscd_run_prune (void *p)
 	  time_t prune_now = dbs[my_number].clear_cache ? LONG_MAX : now;
 	  dbs[my_number].clear_cache = 0;
 
+	  /* prune_cache() must be run with prune_lock off since
+	     cache_add() needs to take the lock. */
 	  pthread_mutex_unlock (prune_lock);
+	  pthread_mutex_lock (prune_run_lock);
 
 	  next_wait = prune_cache (&dbs[my_number], prune_now, -1);
 
@@ -1538,6 +1546,7 @@ nscd_run_prune (void *p)
 	      dbs[my_number].head->timestamp = now;
 	    }
 
+	  pthread_mutex_unlock (prune_run_lock);
 	  pthread_mutex_lock (prune_lock);
 
 	  /* Make it known when we will wake up again.  */
diff --git a/nscd/nscd.h b/nscd/nscd.h
index 5c77dd3..a828f3e 100644
--- nscd/nscd.h
+++ nscd/nscd.h
@@ -68,7 +68,7 @@ struct database_dyn
 {
   pthread_rwlock_t lock;
   pthread_cond_t prune_cond;
-  pthread_mutex_t prune_lock;
+  pthread_mutex_t prune_lock, prune_run_lock;
   time_t wakeup_time;
 
   int enabled;