Re: [syzbot] WARNING in batadv_nc_mesh_free

[Pavel Skripkin <paskripkin@gmail.com>]

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On 10/22/21 23:57, Pavel Skripkin wrote:
> On 10/22/21 23:20, syzbot wrote:
>> Hello,
>> 
>> syzbot has tested the proposed patch but the reproducer is still triggering an issue:
>> general protection fault in batadv_nc_purge_paths
> 
> 
> Oh, ok. Next clean up call in batadv_nc_mesh_free() caused GPF, since
> fields are not initialized. Let's try to clean up one by one and do not
> break dependencies.
> 
> Quite ugly one, but idea is correct, I guess
> 
> Also, make each *_init() call clean up all allocated stuff to not call
> corresponding *_free() on error handling path, since it introduces
> problems, as syzbot reported
> 
> 
> 
> 

Whooops.... Forgot to ask syzbot to test the patch

#syz test
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master




With regards,
Pavel Skripkin

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diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c
index 1669744304c5..17687848daec 100644
--- a/net/batman-adv/bridge_loop_avoidance.c
+++ b/net/batman-adv/bridge_loop_avoidance.c
@@ -1560,10 +1560,14 @@ int batadv_bla_init(struct batadv_priv *bat_priv)
 		return 0;
 
 	bat_priv->bla.claim_hash = batadv_hash_new(128);
-	bat_priv->bla.backbone_hash = batadv_hash_new(32);
+	if (!bat_priv->bla.claim_hash)
+		return -ENOMEM;
 
-	if (!bat_priv->bla.claim_hash || !bat_priv->bla.backbone_hash)
+	bat_priv->bla.backbone_hash = batadv_hash_new(32);
+	if (!bat_priv->bla.backbone_hash) {
+		batadv_hash_destroy(bat_priv->bla.claim_hash);
 		return -ENOMEM;
+	}
 
 	batadv_hash_set_lock_class(bat_priv->bla.claim_hash,
 				   &batadv_claim_hash_lock_class_key);
diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index 3ddd66e4c29e..90512ed32348 100644
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -190,29 +190,41 @@ int batadv_mesh_init(struct net_device *soft_iface)
 
 	bat_priv->gw.generation = 0;
 
-	ret = batadv_v_mesh_init(bat_priv);
-	if (ret < 0)
-		goto err;
-
 	ret = batadv_originator_init(bat_priv);
-	if (ret < 0)
-		goto err;
+	if (ret < 0) {
+		atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+		goto err_orig;
+	}
 
 	ret = batadv_tt_init(bat_priv);
-	if (ret < 0)
-		goto err;
+	if (ret < 0) {
+		atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+		goto err_tt;
+	}
+
+	ret = batadv_v_mesh_init(bat_priv);
+	if (ret < 0) {
+		atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+		goto err_v;
+	}
 
 	ret = batadv_bla_init(bat_priv);
-	if (ret < 0)
-		goto err;
+	if (ret < 0) {
+		atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+		goto err_bla;
+	}
 
 	ret = batadv_dat_init(bat_priv);
-	if (ret < 0)
-		goto err;
+	if (ret < 0) {
+		atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+		goto err_dat;
+	}
 
 	ret = batadv_nc_mesh_init(bat_priv);
-	if (ret < 0)
-		goto err;
+	if (ret < 0){
+		atomic_set(&bat_priv->mesh_state, BATADV_MESH_DEACTIVATING);
+		goto err_nc;
+	}
 
 	batadv_gw_init(bat_priv);
 	batadv_mcast_init(bat_priv);
@@ -222,8 +234,20 @@ int batadv_mesh_init(struct net_device *soft_iface)
 
 	return 0;
 
-err:
-	batadv_mesh_free(soft_iface);
+err_nc:
+	batadv_dat_free(bat_priv);
+err_dat:
+	batadv_bla_free(bat_priv);
+err_bla:
+	batadv_v_mesh_free(bat_priv);
+err_v:
+	batadv_tt_free(bat_priv);
+err_tt:
+	batadv_originator_free(bat_priv);
+err_orig:
+	batadv_purge_outstanding_packets(bat_priv, NULL);
+	atomic_set(&bat_priv->mesh_state, BATADV_MESH_INACTIVE);
+
 	return ret;
 }
 
diff --git a/net/batman-adv/network-coding.c b/net/batman-adv/network-coding.c
index 9f06132e007d..0a7f1d36a6a8 100644
--- a/net/batman-adv/network-coding.c
+++ b/net/batman-adv/network-coding.c
@@ -152,8 +152,10 @@ int batadv_nc_mesh_init(struct batadv_priv *bat_priv)
 				   &batadv_nc_coding_hash_lock_class_key);
 
 	bat_priv->nc.decoding_hash = batadv_hash_new(128);
-	if (!bat_priv->nc.decoding_hash)
+	if (!bat_priv->nc.decoding_hash) {
+		batadv_hash_destroy(bat_priv->nc.coding_hash);
 		goto err;
+	}
 
 	batadv_hash_set_lock_class(bat_priv->nc.decoding_hash,
 				   &batadv_nc_decoding_hash_lock_class_key);
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index e0b3dace2020..2c38d9cb4cc4 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -4162,8 +4162,10 @@ int batadv_tt_init(struct batadv_priv *bat_priv)
 		return ret;
 
 	ret = batadv_tt_global_init(bat_priv);
-	if (ret < 0)
+	if (ret < 0) {
+		batadv_tt_global_table_free(bat_priv);
 		return ret;
+	}
 
 	batadv_tvlv_handler_register(bat_priv, batadv_tt_tvlv_ogm_handler_v1,
 				     batadv_tt_tvlv_unicast_handler_v1,