From 62588dbfa7765eaf781dfd6419c6898c8b8ef5fa Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Thu, 31 Oct 2019 18:07:33 +0100
Subject: [PATCH] Modules: fix thread safe context creation crash.

See #6525, this likely creates a NULL deference if the client was
terminated by Redis between the creation of the blocked client and the
creation of the thread safe context.
---
 src/module.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/module.c b/src/module.c
index d55bb4ede..600c0d4a2 100644
--- a/src/module.c
+++ b/src/module.c
@@ -3923,7 +3923,7 @@ RedisModuleCtx *RM_GetThreadSafeContext(RedisModuleBlockedClient *bc) {
     ctx->client = createClient(-1);
     if (bc) {
         selectDb(ctx->client,bc->dbid);
-        ctx->client->id = bc->client->id;
+        if (bc->client) ctx->client->id = bc->client->id;
     }
     return ctx;
 }