[B.A.T.M.A.N.] [PATCH 1/2] batman-adv: Annotate deleting functions with external lock via lockdep

[B.A.T.M.A.N.] [PATCH 1/2] batman-adv: Annotate deleting functions with external lock via lockdep

[Sven Eckelmann]

Functions which use (h)list_del* are requiring correct locking when they
operate on global lists. Most of the time the search in the list and the
delete are done in the same function. All other cases should have it
visible that they require a special lock to avoid race conditions.

Lockdep asserts can be used to check these problem during runtime when the
lockdep functionality is enabled.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 net/batman-adv/main.c              | 11 ++++++++---
 net/batman-adv/multicast.c         | 13 +++++++++++--
 net/batman-adv/network-coding.c    |  4 ++++
 net/batman-adv/translation-table.c |  2 ++
 4 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/net/batman-adv/main.c b/net/batman-adv/main.c
index 40750cb..e71166a 100644
--- a/net/batman-adv/main.c
+++ b/net/batman-adv/main.c
@@ -30,6 +30,7 @@
 #include <linux/ipv6.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
+#include <linux/lockdep.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/netdevice.h>
@@ -737,13 +738,17 @@ static u16 batadv_tvlv_container_list_size(struct batadv_priv *bat_priv)
 /**
  * batadv_tvlv_container_remove - remove tvlv container from the tvlv container
  *  list
+ * @bat_priv: the bat priv with all the soft interface information
  * @tvlv: the to be removed tvlv container
  *
  * Has to be called with the appropriate locks being acquired
  * (tvlv.container_list_lock).
  */
-static void batadv_tvlv_container_remove(struct batadv_tvlv_container *tvlv)
+static void batadv_tvlv_container_remove(struct batadv_priv *bat_priv,
+					 struct batadv_tvlv_container *tvlv)
 {
+	lockdep_assert_held(&bat_priv->tvlv.handler_list_lock);
+
 	if (!tvlv)
 		return;
 
@@ -768,7 +773,7 @@ void batadv_tvlv_container_unregister(struct batadv_priv *bat_priv,
 
 	spin_lock_bh(&bat_priv->tvlv.container_list_lock);
 	tvlv = batadv_tvlv_container_get(bat_priv, type, version);
-	batadv_tvlv_container_remove(tvlv);
+	batadv_tvlv_container_remove(bat_priv, tvlv);
 	spin_unlock_bh(&bat_priv->tvlv.container_list_lock);
 }
 
@@ -807,7 +812,7 @@ void batadv_tvlv_container_register(struct batadv_priv *bat_priv,
 
 	spin_lock_bh(&bat_priv->tvlv.container_list_lock);
 	tvlv_old = batadv_tvlv_container_get(bat_priv, type, version);
-	batadv_tvlv_container_remove(tvlv_old);
+	batadv_tvlv_container_remove(bat_priv, tvlv_old);
 	hlist_add_head(&tvlv_new->list, &bat_priv->tvlv.container_list);
 	spin_unlock_bh(&bat_priv->tvlv.container_list_lock);
 }
diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index c64d9b1..f9190ad 100644
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -31,6 +31,7 @@
 #include <linux/ip.h>
 #include <linux/ipv6.h>
 #include <linux/list.h>
+#include <linux/lockdep.h>
 #include <linux/netdevice.h>
 #include <linux/rculist.h>
 #include <linux/rcupdate.h>
@@ -103,15 +104,19 @@ static bool batadv_mcast_mla_is_duplicate(u8 *mcast_addr,
 
 /**
  * batadv_mcast_mla_list_free - free a list of multicast addresses
+ * @bat_priv: the bat priv with all the soft interface information
  * @mcast_list: the list to free
  *
  * Removes and frees all items in the given mcast_list.
  */
-static void batadv_mcast_mla_list_free(struct hlist_head *mcast_list)
+static void batadv_mcast_mla_list_free(struct batadv_priv *bat_priv,
+				       struct hlist_head *mcast_list)
 {
 	struct batadv_hw_addr *mcast_entry;
 	struct hlist_node *tmp;
 
+	lockdep_assert_held(&bat_priv->tt.commit_lock);
+
 	hlist_for_each_entry_safe(mcast_entry, tmp, mcast_list, list) {
 		hlist_del(&mcast_entry->list);
 		kfree(mcast_entry);
@@ -134,6 +139,8 @@ static void batadv_mcast_mla_tt_retract(struct batadv_priv *bat_priv,
 	struct batadv_hw_addr *mcast_entry;
 	struct hlist_node *tmp;
 
+	lockdep_assert_held(&bat_priv->tt.commit_lock);
+
 	hlist_for_each_entry_safe(mcast_entry, tmp, &bat_priv->mcast.mla_list,
 				  list) {
 		if (mcast_list &&
@@ -164,6 +171,8 @@ static void batadv_mcast_mla_tt_add(struct batadv_priv *bat_priv,
 	struct batadv_hw_addr *mcast_entry;
 	struct hlist_node *tmp;
 
+	lockdep_assert_held(&bat_priv->tt.commit_lock);
+
 	if (!mcast_list)
 		return;
 
@@ -268,7 +277,7 @@ update:
 	batadv_mcast_mla_tt_add(bat_priv, &mcast_list);
 
 out:
-	batadv_mcast_mla_list_free(&mcast_list);
+	batadv_mcast_mla_list_free(bat_priv, &mcast_list);
 }
 
 /**
diff --git a/net/batman-adv/network-coding.c b/net/batman-adv/network-coding.c
index 62defe0..9700223 100644
--- a/net/batman-adv/network-coding.c
+++ b/net/batman-adv/network-coding.c
@@ -586,6 +586,8 @@ static bool batadv_nc_sniffed_purge(struct batadv_priv *bat_priv,
 	unsigned long timeout = bat_priv->nc.max_buffer_time;
 	bool res = false;
 
+	lockdep_assert_held(&nc_path->packet_list_lock);
+
 	/* Packets are added to tail, so the remaining packets did not time
 	 * out and we can stop processing the current queue
 	 */
@@ -622,6 +624,8 @@ static bool batadv_nc_fwd_flush(struct batadv_priv *bat_priv,
 {
 	unsigned long timeout = bat_priv->nc.max_fwd_delay;
 
+	lockdep_assert_held(&nc_path->packet_list_lock);
+
 	/* Packets are added to tail, so the remaining packets did not time
 	 * out and we can stop processing the current queue
 	 */
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index e96710c..7490006 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -1669,6 +1669,8 @@ static void
 _batadv_tt_global_del_orig_entry(struct batadv_tt_global_entry *tt_global_entry,
 				 struct batadv_tt_orig_list_entry *orig_entry)
 {
+	lockdep_assert_held(&tt_global_entry->list_lock);
+
 	batadv_tt_global_size_dec(orig_entry->orig_node,
 				  tt_global_entry->common.vid);
 	atomic_dec(&tt_global_entry->orig_list_count);
-- 
2.1.4

[B.A.T.M.A.N.] [PATCH 2/2] batman-adv: Add lockdep_asserts for documented external locks

[Sven Eckelmann]

Some functions already have documentation about looks they require inside
their kerneldoc header. These can be directly tested during runtime using
the lockdep asserts.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
---
 net/batman-adv/fragmentation.c     | 2 ++
 net/batman-adv/multicast.c         | 6 ++++++
 net/batman-adv/translation-table.c | 2 ++
 3 files changed, 10 insertions(+)

diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
index ec5f7bc..e11325b 100644
--- a/net/batman-adv/fragmentation.c
+++ b/net/batman-adv/fragmentation.c
@@ -112,6 +112,8 @@ static int batadv_frag_size_limit(void)
 static bool batadv_frag_init_chain(struct batadv_frag_table_entry *chain,
 				   u16 seqno)
 {
+	lockdep_assert_held(&chain->lock);
+
 	if (chain->seqno == seqno)
 		return false;
 
diff --git a/net/batman-adv/multicast.c b/net/batman-adv/multicast.c
index f9190ad..cd8eaca 100644
--- a/net/batman-adv/multicast.c
+++ b/net/batman-adv/multicast.c
@@ -609,6 +609,8 @@ static void batadv_mcast_want_unsnoop_update(struct batadv_priv *bat_priv,
 	struct hlist_node *node = &orig->mcast_want_all_unsnoopables_node;
 	struct hlist_head *head = &bat_priv->mcast.want_all_unsnoopables_list;
 
+	lockdep_assert_held(&orig->mcast_handler_lock);
+
 	/* switched from flag unset to set */
 	if (mcast_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES &&
 	    !(orig->mcast_flags & BATADV_MCAST_WANT_ALL_UNSNOOPABLES)) {
@@ -652,6 +654,8 @@ static void batadv_mcast_want_ipv4_update(struct batadv_priv *bat_priv,
 	struct hlist_node *node = &orig->mcast_want_all_ipv4_node;
 	struct hlist_head *head = &bat_priv->mcast.want_all_ipv4_list;
 
+	lockdep_assert_held(&orig->mcast_handler_lock);
+
 	/* switched from flag unset to set */
 	if (mcast_flags & BATADV_MCAST_WANT_ALL_IPV4 &&
 	    !(orig->mcast_flags & BATADV_MCAST_WANT_ALL_IPV4)) {
@@ -695,6 +699,8 @@ static void batadv_mcast_want_ipv6_update(struct batadv_priv *bat_priv,
 	struct hlist_node *node = &orig->mcast_want_all_ipv6_node;
 	struct hlist_head *head = &bat_priv->mcast.want_all_ipv6_list;
 
+	lockdep_assert_held(&orig->mcast_handler_lock);
+
 	/* switched from flag unset to set */
 	if (mcast_flags & BATADV_MCAST_WANT_ALL_IPV6 &&
 	    !(orig->mcast_flags & BATADV_MCAST_WANT_ALL_IPV6)) {
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 7490006..a919b5d 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -3264,6 +3264,8 @@ static void batadv_tt_local_purge_pending_clients(struct batadv_priv *bat_priv)
  */
 static void batadv_tt_local_commit_changes_nolock(struct batadv_priv *bat_priv)
 {
+	lockdep_assert_held(&bat_priv->tt.commit_lock);
+
 	/* Update multicast addresses in local translation table */
 	batadv_mcast_mla_update(bat_priv);
 
-- 
2.1.4

Re: [B.A.T.M.A.N.] [PATCH 1/2] batman-adv: Annotate deleting functions with external lock via lockdep

[Antonio Quartulli]

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On 20/06/15 12:13, Sven Eckelmann wrote:
> Functions which use (h)list_del* are requiring correct locking when they
> operate on global lists. Most of the time the search in the list and the
> delete are done in the same function. All other cases should have it
> visible that they require a special lock to avoid race conditions.
> 
> Lockdep asserts can be used to check these problem during runtime when the
> lockdep functionality is enabled.
> 
> Signed-off-by: Sven Eckelmann <sven@narfation.org>

Thanks for this patch Sven!
This should reduce the likelihood of having of making mistakes in the
future (I hope!)

Acked-by: Antonio Quartulli <antonio@meshcoding.com>



-- 
Antonio Quartulli


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Re: [B.A.T.M.A.N.] [PATCH 2/2] batman-adv: Add lockdep_asserts for documented external locks

[Antonio Quartulli]

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On 20/06/15 12:13, Sven Eckelmann wrote:
> Some functions already have documentation about looks they require inside
                                                  ^^^^^

little typ0 here, but I think $somebody can easily fix it before merging
the patch.


> their kerneldoc header. These can be directly tested during runtime using
> the lockdep asserts.
> 
> Signed-off-by: Sven Eckelmann <sven@narfation.org>

Acked-by: Antonio Quartulli <antonio@meshcoding.com>


-- 
Antonio Quartulli


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