From 531647bb1bfb4ce02b691605e11ff4144396442b Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Mon, 10 Apr 2017 13:17:05 +0200
Subject: [PATCH] Make more obvious why there was issue #3843.

---
 src/module.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/module.c b/src/module.c
index b4da7f63..c81330b6 100644
--- a/src/module.c
+++ b/src/module.c
@@ -3236,6 +3236,9 @@ void moduleHandleBlockedClients(void) {
         if (bc->privdata && bc->free_privdata)
             bc->free_privdata(bc->privdata);
         if (c != NULL) unblockClient(c);
+        /* Free 'bc' only after unblocking the client, since it is
+         * referenced in the client blocking context, and must be valid
+         * when calling unblockClient(). */
         zfree(bc);
 
         /* Lock again before to iterate the loop. */