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* pull request for net: batman-adv 2013-05-17
@ 2013-05-17  8:10 ` Antonio Quartulli
  0 siblings, 0 replies; 6+ messages in thread
From: Antonio Quartulli @ 2013-05-17  8:10 UTC (permalink / raw)
  To: davem-fT/PcQaiUtIeIZ0/mPfg9Q
  Cc: netdev-u79uwXL29TY76Z2rM5mHXA,
	b.a.t.m.a.n-ZwoEplunGu2X36UT3dwllkB+6BGkLq7r

Hello David,

here you have one fix intended for net/linux-3.10.
This patch is fixing a global fault protection that can be triggered on module
removal due to the double invocation of call_rcu() in chain.

While fixing, the patch is also adding some kernel doc to the changed functions.
Consider queueing this patch to -stable.



Please pull or let me know if there is any problem!

Thank you,
	Antonio


The following changes since commit b0ce3508b25ea6fa10ae3ca254de1d695b521702:

  bonding: allow TSO being set on bonding master (2013-05-16 15:02:01 -0700)

are available in the git repository at:

  git://git.open-mesh.org/linux-merge.git tags/batman-adv-fix-for-davem

for you to fetch changes up to 72822225bd41320a98f5d7cde38317766e18983f:

  batman-adv: Fix rcu_barrier() miss due to double call_rcu() in TT code (2013-05-17 09:54:28 +0200)

----------------------------------------------------------------
Included changes:
- fix global protection fault by avoiding double call_rcu

----------------------------------------------------------------
Linus Lüssing (1):
      batman-adv: Fix rcu_barrier() miss due to double call_rcu() in TT code

 net/batman-adv/originator.c        | 16 ++++++++++++++++
 net/batman-adv/originator.h        |  1 +
 net/batman-adv/translation-table.c |  7 ++++++-
 3 files changed, 23 insertions(+), 1 deletion(-)

^ permalink raw reply	[flat|nested] 6+ messages in thread
* [B.A.T.M.A.N.] pull request for net: batman-adv 2013-05-17
@ 2013-05-17  8:10 ` Antonio Quartulli
  0 siblings, 0 replies; 6+ messages in thread
From: Antonio Quartulli @ 2013-05-17  8:10 UTC (permalink / raw)
  To: davem; +Cc: netdev, b.a.t.m.a.n

Hello David,

here you have one fix intended for net/linux-3.10.
This patch is fixing a global fault protection that can be triggered on module
removal due to the double invocation of call_rcu() in chain.

While fixing, the patch is also adding some kernel doc to the changed functions.
Consider queueing this patch to -stable.



Please pull or let me know if there is any problem!

Thank you,
	Antonio


The following changes since commit b0ce3508b25ea6fa10ae3ca254de1d695b521702:

  bonding: allow TSO being set on bonding master (2013-05-16 15:02:01 -0700)

are available in the git repository at:

  git://git.open-mesh.org/linux-merge.git tags/batman-adv-fix-for-davem

for you to fetch changes up to 72822225bd41320a98f5d7cde38317766e18983f:

  batman-adv: Fix rcu_barrier() miss due to double call_rcu() in TT code (2013-05-17 09:54:28 +0200)

----------------------------------------------------------------
Included changes:
- fix global protection fault by avoiding double call_rcu

----------------------------------------------------------------
Linus Lüssing (1):
      batman-adv: Fix rcu_barrier() miss due to double call_rcu() in TT code

 net/batman-adv/originator.c        | 16 ++++++++++++++++
 net/batman-adv/originator.h        |  1 +
 net/batman-adv/translation-table.c |  7 ++++++-
 3 files changed, 23 insertions(+), 1 deletion(-)

^ permalink raw reply	[flat|nested] 6+ messages in thread
* [PATCH] batman-adv: Fix rcu_barrier() miss due to double call_rcu() in TT code
  2013-05-17  8:10 ` [B.A.T.M.A.N.] " Antonio Quartulli
@ 2013-05-17  8:10   ` Antonio Quartulli
  -1 siblings, 0 replies; 6+ messages in thread
From: Antonio Quartulli @ 2013-05-17  8:10 UTC (permalink / raw)
  To: davem
  Cc: netdev, b.a.t.m.a.n, Linus Lüssing, Marek Lindner,
	Antonio Quartulli

From: Linus Lüssing <linus.luessing@web.de>

rcu_barrier() only waits for the currently scheduled rcu functions
to finish - it won't wait for any function scheduled via another
call_rcu() within an rcu scheduled function.

Unfortunately our batadv_tt_orig_list_entry_free_ref() does just that,
via a batadv_orig_node_free_ref() call, leading to our rcu_barrier()
call potentially missing such a batadv_orig_node_free_ref().

This patch fixes this issue by calling the batadv_orig_node_free_rcu()
directly from the rcu callback, removing the unnecessary, additional
call_rcu() layer here.

Signed-off-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Acked-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
---
 net/batman-adv/originator.c        | 16 ++++++++++++++++
 net/batman-adv/originator.h        |  1 +
 net/batman-adv/translation-table.c |  7 ++++++-
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 2f34525..fad1a20 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -156,12 +156,28 @@ static void batadv_orig_node_free_rcu(struct rcu_head *rcu)
 	kfree(orig_node);
 }
 
+/**
+ * batadv_orig_node_free_ref - decrement the orig node refcounter and possibly
+ * schedule an rcu callback for freeing it
+ * @orig_node: the orig node to free
+ */
 void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node)
 {
 	if (atomic_dec_and_test(&orig_node->refcount))
 		call_rcu(&orig_node->rcu, batadv_orig_node_free_rcu);
 }
 
+/**
+ * batadv_orig_node_free_ref_now - decrement the orig node refcounter and
+ * possibly free it (without rcu callback)
+ * @orig_node: the orig node to free
+ */
+void batadv_orig_node_free_ref_now(struct batadv_orig_node *orig_node)
+{
+	if (atomic_dec_and_test(&orig_node->refcount))
+		batadv_orig_node_free_rcu(&orig_node->rcu);
+}
+
 void batadv_originator_free(struct batadv_priv *bat_priv)
 {
 	struct batadv_hashtable *hash = bat_priv->orig_hash;
diff --git a/net/batman-adv/originator.h b/net/batman-adv/originator.h
index 7df48fa..734e5a3 100644
--- a/net/batman-adv/originator.h
+++ b/net/batman-adv/originator.h
@@ -26,6 +26,7 @@ int batadv_originator_init(struct batadv_priv *bat_priv);
 void batadv_originator_free(struct batadv_priv *bat_priv);
 void batadv_purge_orig_ref(struct batadv_priv *bat_priv);
 void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node);
+void batadv_orig_node_free_ref_now(struct batadv_orig_node *orig_node);
 struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv,
 					      const uint8_t *addr);
 struct batadv_neigh_node *
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 5e89dee..9e87485 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -144,7 +144,12 @@ static void batadv_tt_orig_list_entry_free_rcu(struct rcu_head *rcu)
 	struct batadv_tt_orig_list_entry *orig_entry;
 
 	orig_entry = container_of(rcu, struct batadv_tt_orig_list_entry, rcu);
-	batadv_orig_node_free_ref(orig_entry->orig_node);
+
+	/* We are in an rcu callback here, therefore we cannot use
+	 * batadv_orig_node_free_ref() and its call_rcu():
+	 * An rcu_barrier() wouldn't wait for that to finish
+	 */
+	batadv_orig_node_free_ref_now(orig_entry->orig_node);
 	kfree(orig_entry);
 }
 
-- 
1.8.1.5

^ permalink raw reply related	[flat|nested] 6+ messages in thread
* [B.A.T.M.A.N.] [PATCH] batman-adv: Fix rcu_barrier() miss due to double call_rcu() in TT code
@ 2013-05-17  8:10   ` Antonio Quartulli
  0 siblings, 0 replies; 6+ messages in thread
From: Antonio Quartulli @ 2013-05-17  8:10 UTC (permalink / raw)
  To: davem; +Cc: netdev, b.a.t.m.a.n, Marek Lindner, Antonio Quartulli

From: Linus Lüssing <linus.luessing@web.de>

rcu_barrier() only waits for the currently scheduled rcu functions
to finish - it won't wait for any function scheduled via another
call_rcu() within an rcu scheduled function.

Unfortunately our batadv_tt_orig_list_entry_free_ref() does just that,
via a batadv_orig_node_free_ref() call, leading to our rcu_barrier()
call potentially missing such a batadv_orig_node_free_ref().

This patch fixes this issue by calling the batadv_orig_node_free_rcu()
directly from the rcu callback, removing the unnecessary, additional
call_rcu() layer here.

Signed-off-by: Linus Lüssing <linus.luessing@web.de>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Acked-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
---
 net/batman-adv/originator.c        | 16 ++++++++++++++++
 net/batman-adv/originator.h        |  1 +
 net/batman-adv/translation-table.c |  7 ++++++-
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c
index 2f34525..fad1a20 100644
--- a/net/batman-adv/originator.c
+++ b/net/batman-adv/originator.c
@@ -156,12 +156,28 @@ static void batadv_orig_node_free_rcu(struct rcu_head *rcu)
 	kfree(orig_node);
 }
 
+/**
+ * batadv_orig_node_free_ref - decrement the orig node refcounter and possibly
+ * schedule an rcu callback for freeing it
+ * @orig_node: the orig node to free
+ */
 void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node)
 {
 	if (atomic_dec_and_test(&orig_node->refcount))
 		call_rcu(&orig_node->rcu, batadv_orig_node_free_rcu);
 }
 
+/**
+ * batadv_orig_node_free_ref_now - decrement the orig node refcounter and
+ * possibly free it (without rcu callback)
+ * @orig_node: the orig node to free
+ */
+void batadv_orig_node_free_ref_now(struct batadv_orig_node *orig_node)
+{
+	if (atomic_dec_and_test(&orig_node->refcount))
+		batadv_orig_node_free_rcu(&orig_node->rcu);
+}
+
 void batadv_originator_free(struct batadv_priv *bat_priv)
 {
 	struct batadv_hashtable *hash = bat_priv->orig_hash;
diff --git a/net/batman-adv/originator.h b/net/batman-adv/originator.h
index 7df48fa..734e5a3 100644
--- a/net/batman-adv/originator.h
+++ b/net/batman-adv/originator.h
@@ -26,6 +26,7 @@ int batadv_originator_init(struct batadv_priv *bat_priv);
 void batadv_originator_free(struct batadv_priv *bat_priv);
 void batadv_purge_orig_ref(struct batadv_priv *bat_priv);
 void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node);
+void batadv_orig_node_free_ref_now(struct batadv_orig_node *orig_node);
 struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv,
 					      const uint8_t *addr);
 struct batadv_neigh_node *
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 5e89dee..9e87485 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -144,7 +144,12 @@ static void batadv_tt_orig_list_entry_free_rcu(struct rcu_head *rcu)
 	struct batadv_tt_orig_list_entry *orig_entry;
 
 	orig_entry = container_of(rcu, struct batadv_tt_orig_list_entry, rcu);
-	batadv_orig_node_free_ref(orig_entry->orig_node);
+
+	/* We are in an rcu callback here, therefore we cannot use
+	 * batadv_orig_node_free_ref() and its call_rcu():
+	 * An rcu_barrier() wouldn't wait for that to finish
+	 */
+	batadv_orig_node_free_ref_now(orig_entry->orig_node);
 	kfree(orig_entry);
 }
 
-- 
1.8.1.5


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* Re: pull request for net: batman-adv 2013-05-17
  2013-05-17  8:10 ` [B.A.T.M.A.N.] " Antonio Quartulli
@ 2013-05-17  8:41   ` David Miller
  -1 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2013-05-17  8:41 UTC (permalink / raw)
  To: ordex; +Cc: netdev, b.a.t.m.a.n

From: Antonio Quartulli <ordex@autistici.org>
Date: Fri, 17 May 2013 10:10:10 +0200

> here you have one fix intended for net/linux-3.10.
> This patch is fixing a global fault protection that can be triggered on module
> removal due to the double invocation of call_rcu() in chain.
> 
> While fixing, the patch is also adding some kernel doc to the changed functions.
> Consider queueing this patch to -stable.

Pulled, thanks.

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [B.A.T.M.A.N.] pull request for net: batman-adv 2013-05-17
@ 2013-05-17  8:41   ` David Miller
  0 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2013-05-17  8:41 UTC (permalink / raw)
  To: ordex; +Cc: netdev, b.a.t.m.a.n

From: Antonio Quartulli <ordex@autistici.org>
Date: Fri, 17 May 2013 10:10:10 +0200

> here you have one fix intended for net/linux-3.10.
> This patch is fixing a global fault protection that can be triggered on module
> removal due to the double invocation of call_rcu() in chain.
> 
> While fixing, the patch is also adding some kernel doc to the changed functions.
> Consider queueing this patch to -stable.

Pulled, thanks.

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-05-17  8:41 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-05-17  8:10 pull request for net: batman-adv 2013-05-17 Antonio Quartulli
2013-05-17  8:10 ` [B.A.T.M.A.N.] " Antonio Quartulli
2013-05-17  8:10 ` [PATCH] batman-adv: Fix rcu_barrier() miss due to double call_rcu() in TT code Antonio Quartulli
2013-05-17  8:10   ` [B.A.T.M.A.N.] " Antonio Quartulli
2013-05-17  8:41 ` pull request for net: batman-adv 2013-05-17 David Miller
2013-05-17  8:41   ` [B.A.T.M.A.N.] " David Miller

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