fix crash in redis-cli after making cluster backup (#8267)

getRDB is "designed" to work in two modes: one for redis-cli --rdb and
one for redis-cli --cluster backup.
in the later case it uses the hiredis connection from the cluster nodes
and it used to free it without nullifying the context, so a later
attempt to free the context would crash.

I suppose the reason it seems to want to free the hiredis context ASAP
is that it wants to disconnect the replica link, so that replication
buffers will not be accumulated.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/redis-cli.c b/src/redis-cli.c
index ff29de748..31d2360c9 100644
--- a/src/redis-cli.c
+++ b/src/redis-cli.c
@@ -7132,7 +7132,9 @@ static void getRDB(clusterManagerNode *node) {
     } else {
         fprintf(stderr,"Transfer finished with success.\n");
     }
-    redisFree(s); /* Close the file descriptor ASAP as fsync() may take time. */
+    redisFree(s); /* Close the connection ASAP as fsync() may take time. */
+    if (node)
+        node->context = NULL;
     fsync(fd);
     close(fd);
     fprintf(stderr,"Transfer finished with success.\n");