From: Sven Eckelmann Date: Tue, 26 May 2026 19:50:51 +0000 (+0200) Subject: batman-adv: bla: annotate lasttime access with READ/WRITE_ONCE X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=98b0fb191c878a64cbaebfe231d96d57576acf8c;p=thirdparty%2Flinux.git batman-adv: bla: annotate lasttime access with READ/WRITE_ONCE The lasttime field for claim, backbone_gw, and loopdetect tracks the jiffies value of the most recent activity and is used to detect timeouts. These accesses are not consistently protected by a lock, so READ_ONCE/WRITE_ONCE must be used to prevent data races caused by compiler optimizations. Cc: stable@kernel.org Fixes: 23721387c409 ("batman-adv: add basic bridge loop avoidance code") Signed-off-by: Sven Eckelmann --- diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c index 87d6b11161e4a..0461f11227d06 100644 --- a/net/batman-adv/bridge_loop_avoidance.c +++ b/net/batman-adv/bridge_loop_avoidance.c @@ -513,7 +513,7 @@ batadv_bla_get_backbone_gw(struct batadv_priv *bat_priv, const u8 *orig, return NULL; entry->vid = vid; - entry->lasttime = jiffies; + WRITE_ONCE(entry->lasttime, jiffies); entry->crc = BATADV_BLA_CRC_INIT; entry->bat_priv = bat_priv; spin_lock_init(&entry->crc_lock); @@ -581,7 +581,7 @@ batadv_bla_update_own_backbone_gw(struct batadv_priv *bat_priv, if (unlikely(!backbone_gw)) return; - backbone_gw->lasttime = jiffies; + WRITE_ONCE(backbone_gw->lasttime, jiffies); batadv_backbone_gw_put(backbone_gw); } @@ -715,7 +715,7 @@ static void batadv_bla_add_claim(struct batadv_priv *bat_priv, ether_addr_copy(claim->addr, mac); spin_lock_init(&claim->backbone_lock); claim->vid = vid; - claim->lasttime = jiffies; + WRITE_ONCE(claim->lasttime, jiffies); kref_get(&backbone_gw->refcount); claim->backbone_gw = backbone_gw; kref_init(&claim->refcount); @@ -737,7 +737,7 @@ static void batadv_bla_add_claim(struct batadv_priv *bat_priv, return; } } else { - claim->lasttime = jiffies; + WRITE_ONCE(claim->lasttime, jiffies); if (claim->backbone_gw == backbone_gw) /* no need to register a new backbone */ goto claim_free_ref; @@ -770,7 +770,7 @@ static void batadv_bla_add_claim(struct batadv_priv *bat_priv, spin_lock_bh(&backbone_gw->crc_lock); backbone_gw->crc ^= crc16(0, claim->addr, ETH_ALEN); spin_unlock_bh(&backbone_gw->crc_lock); - backbone_gw->lasttime = jiffies; + WRITE_ONCE(backbone_gw->lasttime, jiffies); claim_free_ref: batadv_claim_put(claim); @@ -859,7 +859,7 @@ static bool batadv_handle_announce(struct batadv_priv *bat_priv, u8 *an_addr, return true; /* handle as ANNOUNCE frame */ - backbone_gw->lasttime = jiffies; + WRITE_ONCE(backbone_gw->lasttime, jiffies); crc = ntohs(*((__force __be16 *)(&an_addr[4]))); batadv_dbg(BATADV_DBG_BLA, bat_priv, @@ -1254,7 +1254,7 @@ static void batadv_bla_purge_backbone_gw(struct batadv_priv *bat_priv, int now) head, hash_entry) { if (now) goto purge_now; - if (!batadv_has_timed_out(backbone_gw->lasttime, + if (!batadv_has_timed_out(READ_ONCE(backbone_gw->lasttime), BATADV_BLA_BACKBONE_TIMEOUT)) continue; @@ -1335,7 +1335,7 @@ static void batadv_bla_purge_claims(struct batadv_priv *bat_priv, primary_if->net_dev->dev_addr)) goto skip; - if (!batadv_has_timed_out(claim->lasttime, + if (!batadv_has_timed_out(READ_ONCE(claim->lasttime), BATADV_BLA_CLAIM_TIMEOUT)) goto skip; @@ -1495,7 +1495,7 @@ static void batadv_bla_periodic_work(struct work_struct *work) eth_random_addr(bat_priv->bla.loopdetect_addr); bat_priv->bla.loopdetect_addr[0] = 0xba; bat_priv->bla.loopdetect_addr[1] = 0xbe; - bat_priv->bla.loopdetect_lasttime = jiffies; + WRITE_ONCE(bat_priv->bla.loopdetect_lasttime, jiffies); atomic_set(&bat_priv->bla.loopdetect_next, BATADV_BLA_LOOPDETECT_PERIODS); @@ -1516,7 +1516,7 @@ static void batadv_bla_periodic_work(struct work_struct *work) primary_if->net_dev->dev_addr)) continue; - backbone_gw->lasttime = jiffies; + WRITE_ONCE(backbone_gw->lasttime, jiffies); batadv_bla_send_announce(bat_priv, backbone_gw); if (send_loopdetect) @@ -1900,7 +1900,7 @@ batadv_bla_loopdetect_check(struct batadv_priv *bat_priv, struct sk_buff *skb, /* If the packet came too late, don't forward it on the mesh * but don't consider that as loop. It might be a coincidence. */ - if (batadv_has_timed_out(bat_priv->bla.loopdetect_lasttime, + if (batadv_has_timed_out(READ_ONCE(bat_priv->bla.loopdetect_lasttime), BATADV_BLA_LOOPDETECT_TIMEOUT)) return true; @@ -2015,7 +2015,7 @@ bool batadv_bla_rx(struct batadv_priv *bat_priv, struct sk_buff *skb, if (own_claim) { /* ... allow it in any case */ - claim->lasttime = jiffies; + WRITE_ONCE(claim->lasttime, jiffies); goto allow; } @@ -2117,7 +2117,7 @@ bool batadv_bla_tx(struct batadv_priv *bat_priv, struct sk_buff *skb, /* if yes, the client has roamed and we have * to unclaim it. */ - if (batadv_has_timed_out(claim->lasttime, 100)) { + if (batadv_has_timed_out(READ_ONCE(claim->lasttime), 100)) { /* only unclaim if the last claim entry is * older than 100 ms to make sure we really * have a roaming client here. @@ -2362,7 +2362,7 @@ batadv_bla_backbone_dump_entry(struct sk_buff *msg, u32 portid, backbone_crc = backbone_gw->crc; spin_unlock_bh(&backbone_gw->crc_lock); - msecs = jiffies_to_msecs(jiffies - backbone_gw->lasttime); + msecs = jiffies_to_msecs(jiffies - READ_ONCE(backbone_gw->lasttime)); if (is_own) if (nla_put_flag(msg, BATADV_ATTR_BLA_OWN)) {