DAOS-15045 vos: check tls before accessing

Check vos tls in vos_pool_hhash_get(), since it maybe
called in the system xstream.

Required-githooks: true

Signed-off-by: Di Wang <di.wang@intel.com>

src/vos/vos_pool.c

@@ -841,11 +841,14 @@ pool_link(struct vos_pool *pool, struct d_uuid *ukey, daos_handle_t *poh)
 static int
 pool_lookup(struct d_uuid *ukey, struct vos_pool **pool)
 {
-	struct d_ulink *hlink;
+	struct d_ulink *hlink = NULL;
 	bool		is_sysdb = uuid_compare(ukey->uuid, *vos_db_pool_uuid()) == 0 ?
 					true : false;
+	struct d_hash_table *htable;
 
-	hlink = d_uhash_link_lookup(vos_pool_hhash_get(is_sysdb), ukey, NULL);
+	htable = vos_pool_hhash_get(is_sysdb);
+	if (htable != NULL)
+		hlink = d_uhash_link_lookup(htable, ukey, NULL);
 	if (hlink == NULL) {
 		D_DEBUG(DB_MGMT, "can't find "DF_UUID"\n", DP_UUID(ukey->uuid));
 		return -DER_NONEXIST;

src/vos/vos_tls.h

@@ -1,5 +1,5 @@
 /**
- * (C) Copyright 2016-2023 Intel Corporation.
+ * (C) Copyright 2016-2024 Intel Corporation.
  *
  * SPDX-License-Identifier: BSD-2-Clause-Patent
  */
@@ -74,6 +74,13 @@ struct vos_tls *vos_tls_get(bool standalone);
 static inline struct d_hash_table *
 vos_pool_hhash_get(bool is_sysdb)
 {
+#ifndef VOS_STANDALONE
+	/* main thread doesn't have TLS and XS context or service thread
+	 * is not initialized yet.
+	 */
+	if (dss_tls_get() == NULL)
+		return NULL;
+#endif
 	return vos_tls_get(is_sysdb)->vtl_pool_hhash;
 }