From 5ec424c6bed98a69bf3e56d24af0393225077f44 Mon Sep 17 00:00:00 2001
From: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Date: Tue, 15 Oct 2024 22:20:55 +0300
Subject: [PATCH] util/mesa-db: Fix crash on compacting empty DB

Fix mesa_db_compact() segfaulting if compacted DB is empty. This crash
happens on writing cache entry that is bigger than DB's size limit and
when DB is empty, which can be triggered by setting DB size to a small
value.

Fixes: 32211788d053 ("util/disk_cache: Add new mesa-db cache type")
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Acked-by: Timothy Arceri <tarceri@itsqueeze.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30988>
---
 src/util/mesa_cache_db.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/util/mesa_cache_db.c b/src/util/mesa_cache_db.c
index f7536ae4a86..4372051c839 100644
--- a/src/util/mesa_cache_db.c
+++ b/src/util/mesa_cache_db.c
@@ -614,6 +614,9 @@ mesa_db_compact(struct mesa_cache_db *db, int64_t blob_size,
       return false;
 
    num_entries = _mesa_hash_table_num_entries(db->index_db->table);
+   if (!num_entries)
+      return true;
+
    entries = calloc(num_entries, sizeof(*entries));
    if (!entries)
       return false;