Don't put clients into unblocked list multiple times

1 files changed, 6 insertions, 2 deletions

diff --git a/src/blocked.c b/src/blocked.c
index 8acfb8184..3442b9dd4 100644
--- a/src/blocked.c
+++ b/src/blocked.c
@@ -137,10 +137,14 @@ void unblockClient(redisClient *c) {
     /* Clear the flags, and put the client in the unblocked list so that
      * we'll process new commands in its query buffer ASAP. */
     c->flags &= ~REDIS_BLOCKED;
-    c->flags |= REDIS_UNBLOCKED;
     c->btype = REDIS_BLOCKED_NONE;
     server.bpop_blocked_clients--;
-    listAddNodeTail(server.unblocked_clients,c);
+    /* The client may already be into the unblocked list because of a previous
+     * blocking operation, don't add back it into the list multiple times. */
+    if (!(c->flags & REDIS_UNBLOCKED)) {
+        c->flags |= REDIS_UNBLOCKED;
+        listAddNodeTail(server.unblocked_clients,c);
+    }
 }
 
 /* This function gets called when a blocked client timed out in order to