From: Sven Eckelmann The last_recv_time field for batadv_tp_receiver 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: 33a3bb4a3345 ("batman-adv: throughput meter implementation") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/tp_meter.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/batman-adv/tp_meter.c b/net/batman-adv/tp_meter.c index 259ac8c307359..fb87fa141e32a 100644 --- a/net/batman-adv/tp_meter.c +++ b/net/batman-adv/tp_meter.c @@ -1290,7 +1290,7 @@ static void batadv_tp_receiver_shutdown(struct timer_list *t) bat_priv = tp_vars->common.bat_priv; /* if there is recent activity rearm the timer */ - if (!batadv_has_timed_out(tp_vars->last_recv_time, + if (!batadv_has_timed_out(READ_ONCE(tp_vars->last_recv_time), BATADV_TP_RECV_TIMEOUT)) { /* reset the receiver shutdown timer */ batadv_tp_reset_receiver_timer(tp_vars); @@ -1532,7 +1532,7 @@ batadv_tp_init_recv(struct batadv_priv *bat_priv, tp_vars = batadv_tp_list_find_receiver_session(bat_priv, icmp->orig, icmp->session); if (tp_vars) { - tp_vars->last_recv_time = jiffies; + WRITE_ONCE(tp_vars->last_recv_time, jiffies); goto out_unlock; } @@ -1562,7 +1562,7 @@ batadv_tp_init_recv(struct batadv_priv *bat_priv, kref_get(&tp_vars->common.refcount); timer_setup(&tp_vars->common.timer, batadv_tp_receiver_shutdown, 0); - tp_vars->last_recv_time = jiffies; + WRITE_ONCE(tp_vars->last_recv_time, jiffies); kref_get(&tp_vars->common.refcount); hlist_add_head_rcu(&tp_vars->common.list, &bat_priv->tp_receiver_list); @@ -1613,7 +1613,7 @@ static void batadv_tp_recv_msg(struct batadv_priv *bat_priv, goto out; } - tp_vars->last_recv_time = jiffies; + WRITE_ONCE(tp_vars->last_recv_time, jiffies); } /* if the packet is a duplicate, it may be the case that an ACK has been -- 2.47.3