[PATCH net-next 06/15] batman-adv: ensure u16 aligned mac address arrays on stack
From: Simon Wunderlich <sw@simonwunderlich.de>
Date: 2026-08-31 13:53:22
Also in:
batman
Subsystem:
batman advanced, the rest · Maintainers:
Marek Lindner, Simon Wunderlich, Antonio Quartulli, Sven Eckelmann, Linus Torvalds
From: Sven Eckelmann <sven@narfation.org> An u8 array on the stack has a natural alignment of only 1 byte. An u8[ETH_ALEN] array on the stack must therefore be assumed to only be 1 byte aligned. But many etherdevices.h functions are requiring a 2 byte (u16) alignment. Annote all u8[ETH_ALEN] arrays on the stack as __aligned(2) to make sure that the compiler takes care of aligning it correctly. Reported-by: Sashiko <sashiko-bot@kernel.org> Closes: https://sashiko.dev/#/patchset/20260821094813.201800-1-sw%40simonwunderlich.de?part=5 Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de> --- net/batman-adv/bridge_loop_avoidance.c | 6 ++++-- net/batman-adv/distributed-arp-table.c | 8 ++++---- net/batman-adv/mesh-interface.c | 12 ++++++++---- net/batman-adv/multicast.c | 6 +++--- 4 files changed, 19 insertions(+), 13 deletions(-)
diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c
index f635da4b8ca65..ad6ab4a50658f 100644
--- a/net/batman-adv/bridge_loop_avoidance.c
+++ b/net/batman-adv/bridge_loop_avoidance.c@@ -663,7 +663,7 @@ static void batadv_bla_send_request(struct batadv_bla_backbone_gw *backbone_gw) static void batadv_bla_send_announce(struct batadv_priv *bat_priv, struct batadv_bla_backbone_gw *backbone_gw) { - u8 mac[ETH_ALEN]; + u8 mac[ETH_ALEN] __aligned(2); __be16 crc; memcpy(mac, batadv_announce_mac, 4);
@@ -1582,7 +1582,9 @@ static struct lock_class_key batadv_backbone_hash_lock_class_key; */ int batadv_bla_init(struct batadv_priv *bat_priv) { - u8 claim_dest[ETH_ALEN] = {0xff, 0x43, 0x05, 0x00, 0x00, 0x00}; + static const u8 claim_dest[ETH_ALEN] __aligned(2) = { + 0xff, 0x43, 0x05, 0x00, 0x00, 0x00 + }; struct batadv_hard_iface *primary_if; unsigned long entrytime; u16 crc;
diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c
index 270f8d6e29545..a4be5b2a87d7a 100644
--- a/net/batman-adv/distributed-arp-table.c
+++ b/net/batman-adv/distributed-arp-table.c@@ -940,7 +940,7 @@ batadv_dat_cache_dump_entry(struct sk_buff *msg, u32 portid, struct netlink_callback *cb, struct batadv_dat_entry *dat_entry) { - u8 mac[ETH_ALEN]; + u8 mac[ETH_ALEN] __aligned(2); u64 u64_mac; int msecs; void *hdr;
@@ -1236,10 +1236,10 @@ bool batadv_dat_snoop_outgoing_arp_request(struct batadv_priv *bat_priv, { struct net_device *mesh_iface = bat_priv->mesh_iface; struct batadv_dat_entry *dat_entry = NULL; + u8 mac[ETH_ALEN] __aligned(2); struct sk_buff *skb_new; unsigned short vid; bool ret = false; - u8 mac[ETH_ALEN]; int hdr_size = 0; __be32 ip_dst; __be32 ip_src;
@@ -1344,10 +1344,10 @@ bool batadv_dat_snoop_incoming_arp_request(struct batadv_priv *bat_priv, struct sk_buff *skb, int hdr_size) { struct batadv_dat_entry *dat_entry = NULL; + u8 mac[ETH_ALEN] __aligned(2); struct sk_buff *skb_new; unsigned short vid; bool ret = false; - u8 mac[ETH_ALEN]; __be32 ip_src; __be32 ip_dst; u64 u64_mac;
@@ -1474,9 +1474,9 @@ bool batadv_dat_snoop_incoming_arp_reply(struct batadv_priv *bat_priv, struct sk_buff *skb, int hdr_size) { struct batadv_dat_entry *dat_entry = NULL; + u8 mac[ETH_ALEN] __aligned(2); bool dropped = false; unsigned short vid; - u8 mac[ETH_ALEN]; __be32 ip_src; __be32 ip_dst; u64 u64_mac;
diff --git a/net/batman-adv/mesh-interface.c b/net/batman-adv/mesh-interface.c
index e202088cf1fd4..63af21954cf90 100644
--- a/net/batman-adv/mesh-interface.c
+++ b/net/batman-adv/mesh-interface.c@@ -141,9 +141,9 @@ static struct net_device_stats *batadv_interface_stats(struct net_device *dev) static int batadv_interface_set_mac_addr(struct net_device *dev, void *p) { struct batadv_priv *bat_priv = netdev_priv(dev); + u8 old_addr[ETH_ALEN] __aligned(2); struct batadv_meshif_vlan *vlan; struct sockaddr *addr = p; - u8 old_addr[ETH_ALEN]; if (!is_valid_ether_addr(addr->sa_data)) return -EADDRNOTAVAIL;
@@ -213,13 +213,18 @@ static void batadv_interface_set_rx_mode(struct net_device *dev) static netdev_tx_t batadv_interface_tx(struct sk_buff *skb, struct net_device *mesh_iface) { - static const u8 ectp_addr[ETH_ALEN] = {0xCF, 0x00, 0x00, 0x00, 0x00, 0x00}; - static const u8 stp_addr[ETH_ALEN] = {0x01, 0x80, 0xC2, 0x00, 0x00, 0x00}; struct batadv_priv *bat_priv = netdev_priv(mesh_iface); enum batadv_dhcp_recipient dhcp_rcp = BATADV_DHCP_NO; enum batadv_forw_mode forw_mode = BATADV_FORW_BCAST; + static const u8 ectp_addr[ETH_ALEN] __aligned(2) = { + 0xCF, 0x00, 0x00, 0x00, 0x00, 0x00 + }; + static const u8 stp_addr[ETH_ALEN] __aligned(2) = { + 0x01, 0x80, 0xC2, 0x00, 0x00, 0x00 + }; struct batadv_hard_iface *primary_if = NULL; struct batadv_bcast_packet *bcast_packet; + u8 chaddr[ETH_ALEN] __aligned(2); int network_offset = ETH_HLEN; unsigned int header_len = 0; unsigned long brd_delay = 0;
@@ -229,7 +234,6 @@ static netdev_tx_t batadv_interface_tx(struct sk_buff *skb, struct ethhdr *ethhdr; bool do_bcast = false; u8 *dst_hint = NULL; - u8 chaddr[ETH_ALEN]; unsigned short vid; bool client_added; __be16 proto;
diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index 82fd527b61c02..22dd28d5e1abc 100644
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c@@ -368,9 +368,9 @@ batadv_mcast_mla_meshif_get_ipv4(struct net_device *dev, struct hlist_head *mcast_list, struct batadv_mcast_mla_flags *flags) { + u8 mcast_addr[ETH_ALEN] __aligned(2); struct batadv_hw_addr *new; struct in_device *in_dev; - u8 mcast_addr[ETH_ALEN]; struct ip_mc_list *pmc; int ret = 0;
@@ -435,9 +435,9 @@ batadv_mcast_mla_meshif_get_ipv6(struct net_device *dev, struct hlist_head *mcast_list, struct batadv_mcast_mla_flags *flags) { + u8 mcast_addr[ETH_ALEN] __aligned(2); struct batadv_hw_addr *new; struct inet6_dev *in6_dev; - u8 mcast_addr[ETH_ALEN]; struct ifmcaddr6 *pmc6; int ret = 0;
@@ -587,10 +587,10 @@ static int batadv_mcast_mla_bridge_get(struct net_device *dev, struct batadv_mcast_mla_flags *flags) { struct list_head bridge_mcast_list = LIST_HEAD_INIT(bridge_mcast_list); + u8 mcast_addr[ETH_ALEN] __aligned(2); u8 tvlv_flags = flags->tvlv_flags; struct br_ip_list *br_ip_entry; struct batadv_hw_addr *new; - u8 mcast_addr[ETH_ALEN]; struct br_ip_list *tmp; int ret;
--
2.47.3