[Mesa-dev] [PATCH v2 1/5] util/hash_table: Fix hashing in clears on 32-bit

[Tomeu Vizoso]

Some hash functions (eg. key_u64_hash) will attempt to dereference the
key, causing an invalid access when passed DELETED_KEY_VALUE (0x1) or
FREED_KEY_VALUE (0x0).

To avoid this problem, stuff the fake keys into a hash_key_u64 struct
and pass the pointer to it instead.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso at collabora.com>
Suggested-by: Caio Marcelo de Oliveira Filho <caio.oliveira at intel.com>
Cc: Samuel Pitoiset <samuel.pitoiset at gmail.com>
Cc: Nicolai Hähnle <nicolai.haehnle at amd.com>
---
 src/util/hash_table.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/util/hash_table.c b/src/util/hash_table.c
index f58575de558f..58e6fc2d9169 100644
--- a/src/util/hash_table.c
+++ b/src/util/hash_table.c
@@ -667,7 +667,12 @@ _mesa_hash_table_u64_clear(struct hash_table_u64 *ht,
          struct hash_entry entry;
 
          /* Create a fake entry for the delete function. */
-         entry.hash = table->key_hash_function(table->deleted_key);
+         if (sizeof(void *) == 8) {
+            entry.hash = table->key_hash_function(table->deleted_key);
+         } else {
+            struct hash_key_u64 _key = { .value = (uintptr_t)table->deleted_key };
+            entry.hash = table->key_hash_function(&_key);
+         }
          entry.key = table->deleted_key;
          entry.data = ht->deleted_key_data;
 
@@ -682,7 +687,12 @@ _mesa_hash_table_u64_clear(struct hash_table_u64 *ht,
          struct hash_entry entry;
 
          /* Create a fake entry for the delete function. */
-         entry.hash = table->key_hash_function(uint_key(FREED_KEY_VALUE));
+         if (sizeof(void *) == 8) {
+            entry.hash = table->key_hash_function(uint_key(FREED_KEY_VALUE));
+         } else {
+            struct hash_key_u64 _key = { .value = (uintptr_t)FREED_KEY_VALUE };
+            entry.hash = table->key_hash_function(&_key);
+         }
          entry.key = uint_key(FREED_KEY_VALUE);
          entry.data = ht->freed_key_data;
 
-- 
2.20.1