Rasmus Lerdorf 5ebb853e1a Fix segfault during Redis Cluster failover ...

When a Redis Cluster failover occurs, the client detects that the
redirected node was a replica of the old master and calls
cluster_map_keyspace() to remap the cluster topology.

If cluster_map_keyspace() fails (e.g., due to network issues during
the remap), it frees all node objects via zend_hash_clean(c->nodes)
and zeros the master array via memset(c->master, 0, ...).

The bug was that the return value of cluster_map_keyspace() was being
ignored in the failover detection path. This caused the code to
continue with NULL socket pointers, leading to segfaults when
dereferencing c->cmd_sock later.

This fix:
1. Checks the return value of cluster_map_keyspace() in failover
   detection and returns FAILURE if it fails
2. Adds defense-in-depth NULL checks after MOVED and ASK redirections
   to prevent segfaults if slots become NULL for any reason

Fixes production crashes observed during Redis Cluster failovers.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

2025-10-05 21:13:23 -07:00

98 KiB

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