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authorLinus Lüssing <linus.luessing@c0d3.blue>2019-04-24 03:19:14 +0200
committerSimon Wunderlich <sw@simonwunderlich.de>2019-05-06 11:40:46 +0200
commita3c7cd0cdf1107f891aff847ad481e34df727055 (patch)
tree7e22ab7d0e0ec6a22b1095bd2af1b61bf79ad9a2 /net/batman-adv
parentbdc76fd299600736e832f1525f4f23dd210b97cb (diff)
downloadlinux-a3c7cd0cdf1107f891aff847ad481e34df727055.tar.bz2
batman-adv: mcast: fix multicast tt/tvlv worker locking
Syzbot has reported some issues with the locking assumptions made for the multicast tt/tvlv worker: It was able to trigger the WARN_ON() in batadv_mcast_mla_tt_retract() and batadv_mcast_mla_tt_add(). While hard/not reproduceable for us so far it seems that the delayed_work_pending() we use might not be quite safe from reordering. Therefore this patch adds an explicit, new spinlock to protect the update of the mla_list and flags in bat_priv and then removes the WARN_ON(delayed_work_pending()). Reported-by: syzbot+83f2d54ec6b7e417e13f@syzkaller.appspotmail.com Reported-by: syzbot+050927a651272b145a5d@syzkaller.appspotmail.com Reported-by: syzbot+979ffc89b87309b1b94b@syzkaller.appspotmail.com Reported-by: syzbot+f9f3f388440283da2965@syzkaller.appspotmail.com Fixes: cbebd363b2e9 ("batman-adv: Use own timer for multicast TT and TVLV updates") Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> Signed-off-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Diffstat (limited to 'net/batman-adv')
-rw-r--r--net/batman-adv/main.c1
-rw-r--r--net/batman-adv/multicast.c11
-rw-r--r--net/batman-adv/types.h5
3 files changed, 9 insertions, 8 deletions
diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index 75750870cf04..f8725786b596 100644
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -161,6 +161,7 @@ int batadv_mesh_init(struct net_device *soft_iface)
spin_lock_init(&bat_priv->tt.commit_lock);
spin_lock_init(&bat_priv->gw.list_lock);
#ifdef CONFIG_BATMAN_ADV_MCAST
+ spin_lock_init(&bat_priv->mcast.mla_lock);
spin_lock_init(&bat_priv->mcast.want_lists_lock);
#endif
spin_lock_init(&bat_priv->tvlv.container_list_lock);
diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index f91b1b6265cf..1b985ab89c08 100644
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -325,8 +325,6 @@ static void batadv_mcast_mla_list_free(struct hlist_head *mcast_list)
* translation table except the ones listed in the given mcast_list.
*
* If mcast_list is NULL then all are retracted.
- *
- * Do not call outside of the mcast worker! (or cancel mcast worker first)
*/
static void batadv_mcast_mla_tt_retract(struct batadv_priv *bat_priv,
struct hlist_head *mcast_list)
@@ -334,8 +332,6 @@ static void batadv_mcast_mla_tt_retract(struct batadv_priv *bat_priv,
struct batadv_hw_addr *mcast_entry;
struct hlist_node *tmp;
- WARN_ON(delayed_work_pending(&bat_priv->mcast.work));
-
hlist_for_each_entry_safe(mcast_entry, tmp, &bat_priv->mcast.mla_list,
list) {
if (mcast_list &&
@@ -359,8 +355,6 @@ static void batadv_mcast_mla_tt_retract(struct batadv_priv *bat_priv,
*
* Adds multicast listener announcements from the given mcast_list to the
* translation table if they have not been added yet.
- *
- * Do not call outside of the mcast worker! (or cancel mcast worker first)
*/
static void batadv_mcast_mla_tt_add(struct batadv_priv *bat_priv,
struct hlist_head *mcast_list)
@@ -368,8 +362,6 @@ static void batadv_mcast_mla_tt_add(struct batadv_priv *bat_priv,
struct batadv_hw_addr *mcast_entry;
struct hlist_node *tmp;
- WARN_ON(delayed_work_pending(&bat_priv->mcast.work));
-
if (!mcast_list)
return;
@@ -658,7 +650,10 @@ static void batadv_mcast_mla_update(struct work_struct *work)
priv_mcast = container_of(delayed_work, struct batadv_priv_mcast, work);
bat_priv = container_of(priv_mcast, struct batadv_priv, mcast);
+ spin_lock(&bat_priv->mcast.mla_lock);
__batadv_mcast_mla_update(bat_priv);
+ spin_unlock(&bat_priv->mcast.mla_lock);
+
batadv_mcast_start_timer(bat_priv);
}
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index a21b34ed6548..ed0f6a519de5 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -1224,6 +1224,11 @@ struct batadv_priv_mcast {
unsigned char bridged:1;
/**
+ * @mla_lock: a lock protecting mla_list and mla_flags
+ */
+ spinlock_t mla_lock;
+
+ /**
* @num_want_all_unsnoopables: number of nodes wanting unsnoopable IP
* traffic
*/