Bitwise OR/AND assignments in C aren't guaranteed to be atomic. One OGM handler might undo the set/clear of a specific bit from another handler run in between.
Fix this by using the atomic set_bit()/clear_bit() functions.
Fixes: 77ec494490d6 ("batman-adv: Announce new capability via multicast TVLV") Signed-off-by: Linus Lüssing linus.luessing@c0d3.blue --- multicast.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/multicast.c b/multicast.c index 09f2838..00612bf 100644 --- a/multicast.c +++ b/multicast.c @@ -684,7 +684,7 @@ static void batadv_mcast_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv, !(orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST)) { if (orig_initialized) atomic_dec(&bat_priv->mcast.num_disabled); - orig->capabilities |= BATADV_ORIG_CAPA_HAS_MCAST; + set_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities); /* If mcast support is being switched off or if this is an initial * OGM without mcast support then increase the disabled mcast * node counter. @@ -693,10 +693,10 @@ static void batadv_mcast_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv, (orig->capabilities & BATADV_ORIG_CAPA_HAS_MCAST || !orig_initialized)) { atomic_inc(&bat_priv->mcast.num_disabled); - orig->capabilities &= ~BATADV_ORIG_CAPA_HAS_MCAST; + clear_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capabilities); }
- orig->capa_initialized |= BATADV_ORIG_CAPA_HAS_MCAST; + set_bit(BATADV_ORIG_CAPA_HAS_MCAST, &orig->capa_initialized);
if (orig_mcast_enabled && tvlv_value && (tvlv_value_len >= sizeof(mcast_flags)))