From: Andy Strohman <andrew@xxxxxxxxxxxxxxxxxx>
Reference counting is used to ensure that
batadv_hardif_neigh_node and batadv_hard_iface
are not freed before/during
batadv_v_elp_throughput_metric_update work is
finished.
But there isn't a guarantee that the hard if will
remain associated with a soft interface up until
the work is finished.
This fixes a crash triggered by reboot that looks
like this:
Call trace:
batadv_v_mesh_free+0xd0/0x4dc [batman_adv]
batadv_v_elp_throughput_metric_update+0x1c/0xa4
process_one_work+0x178/0x398
worker_thread+0x2e8/0x4d0
kthread+0xd8/0xdc
ret_from_fork+0x10/0x20
(the batadv_v_mesh_free call is misleading,
and does not actually happen)
I was able to make the issue happen more reliably
by changing hardif_neigh->bat_v.metric_work work
to be delayed work. This allowed me to track down
and confirm the fix.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: c833484e5f38 ("batman-adv: ELP - compute the metric based on the estimated throughput")
Signed-off-by: Andy Strohman <andrew@xxxxxxxxxxxxxxxxxx>
[sven@xxxxxxxxxxxxx: prevent entering batadv_v_elp_get_throughput without
soft_iface]
Signed-off-by: Sven Eckelmann <sven@xxxxxxxxxxxxx>
Signed-off-by: Simon Wunderlich <sw@xxxxxxxxxxxxxxxxxx>
---
net/batman-adv/bat_v_elp.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/net/batman-adv/bat_v_elp.c b/net/batman-adv/bat_v_elp.c
index 1d704574e6bf..fbf499bcc671 100644
--- a/net/batman-adv/bat_v_elp.c
+++ b/net/batman-adv/bat_v_elp.c
@@ -66,12 +66,19 @@ static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface)
static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
{
struct batadv_hard_iface *hard_iface = neigh->if_incoming;
+ struct net_device *soft_iface = hard_iface->soft_iface;
struct ethtool_link_ksettings link_settings;
struct net_device *real_netdev;
struct station_info sinfo;
u32 throughput;
int ret;
+ /* don't query throughput when no longer associated with any
+ * batman-adv interface
+ */
+ if (!soft_iface)
+ return BATADV_THROUGHPUT_DEFAULT_VALUE;
+
/* if the user specified a customised value for this interface, then
* return it directly
*/
@@ -141,7 +148,7 @@ static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
default_throughput:
if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) {
- batadv_info(hard_iface->soft_iface,
+ batadv_info(soft_iface,
"WiFi driver or ethtool info does not provide information about link speeds on interface %s, therefore defaulting to hardcoded throughput values of %u.%1u Mbps. Consider overriding the throughput manually or checking your driver.\n",
hard_iface->net_dev->name,
BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
--
2.39.5
