diff options
| author | Linus Lüssing <linus.luessing@web.de> | 2013-04-15 09:43:29 -0400 |
|---|---|---|
| committer | Antonio Quartulli <ordex@autistici.org> | 2013-05-17 03:54:28 -0400 |
| commit | 72822225bd41320a98f5d7cde38317766e18983f (patch) | |
| tree | c1947655ac129d0a1aa3212755097baa9600bb3e /net | |
| parent | b0ce3508b25ea6fa10ae3ca254de1d695b521702 (diff) | |
batman-adv: Fix rcu_barrier() miss due to double call_rcu() in TT code
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>
Diffstat (limited to 'net')
| -rw-r--r-- | net/batman-adv/originator.c | 16 | ||||
| -rw-r--r-- | net/batman-adv/originator.h | 1 | ||||
| -rw-r--r-- | net/batman-adv/translation-table.c | 7 |
3 files changed, 23 insertions, 1 deletions
diff --git a/net/batman-adv/originator.c b/net/batman-adv/originator.c index 2f3452546636..fad1a2093e15 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) | |||
| 156 | kfree(orig_node); | 156 | kfree(orig_node); |
| 157 | } | 157 | } |
| 158 | 158 | ||
| 159 | /** | ||
| 160 | * batadv_orig_node_free_ref - decrement the orig node refcounter and possibly | ||
| 161 | * schedule an rcu callback for freeing it | ||
| 162 | * @orig_node: the orig node to free | ||
| 163 | */ | ||
| 159 | void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node) | 164 | void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node) |
| 160 | { | 165 | { |
| 161 | if (atomic_dec_and_test(&orig_node->refcount)) | 166 | if (atomic_dec_and_test(&orig_node->refcount)) |
| 162 | call_rcu(&orig_node->rcu, batadv_orig_node_free_rcu); | 167 | call_rcu(&orig_node->rcu, batadv_orig_node_free_rcu); |
| 163 | } | 168 | } |
| 164 | 169 | ||
| 170 | /** | ||
| 171 | * batadv_orig_node_free_ref_now - decrement the orig node refcounter and | ||
| 172 | * possibly free it (without rcu callback) | ||
| 173 | * @orig_node: the orig node to free | ||
| 174 | */ | ||
| 175 | void batadv_orig_node_free_ref_now(struct batadv_orig_node *orig_node) | ||
| 176 | { | ||
| 177 | if (atomic_dec_and_test(&orig_node->refcount)) | ||
| 178 | batadv_orig_node_free_rcu(&orig_node->rcu); | ||
| 179 | } | ||
| 180 | |||
| 165 | void batadv_originator_free(struct batadv_priv *bat_priv) | 181 | void batadv_originator_free(struct batadv_priv *bat_priv) |
| 166 | { | 182 | { |
| 167 | struct batadv_hashtable *hash = bat_priv->orig_hash; | 183 | struct batadv_hashtable *hash = bat_priv->orig_hash; |
diff --git a/net/batman-adv/originator.h b/net/batman-adv/originator.h index 7df48fa7669d..734e5a3d8a5b 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); | |||
| 26 | void batadv_originator_free(struct batadv_priv *bat_priv); | 26 | void batadv_originator_free(struct batadv_priv *bat_priv); |
| 27 | void batadv_purge_orig_ref(struct batadv_priv *bat_priv); | 27 | void batadv_purge_orig_ref(struct batadv_priv *bat_priv); |
| 28 | void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node); | 28 | void batadv_orig_node_free_ref(struct batadv_orig_node *orig_node); |
| 29 | void batadv_orig_node_free_ref_now(struct batadv_orig_node *orig_node); | ||
| 29 | struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv, | 30 | struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv, |
| 30 | const uint8_t *addr); | 31 | const uint8_t *addr); |
| 31 | struct batadv_neigh_node * | 32 | struct batadv_neigh_node * |
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c index 5e89deeb9542..9e8748575845 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) | |||
| 144 | struct batadv_tt_orig_list_entry *orig_entry; | 144 | struct batadv_tt_orig_list_entry *orig_entry; |
| 145 | 145 | ||
| 146 | orig_entry = container_of(rcu, struct batadv_tt_orig_list_entry, rcu); | 146 | orig_entry = container_of(rcu, struct batadv_tt_orig_list_entry, rcu); |
| 147 | batadv_orig_node_free_ref(orig_entry->orig_node); | 147 | |
| 148 | /* We are in an rcu callback here, therefore we cannot use | ||
| 149 | * batadv_orig_node_free_ref() and its call_rcu(): | ||
| 150 | * An rcu_barrier() wouldn't wait for that to finish | ||
| 151 | */ | ||
| 152 | batadv_orig_node_free_ref_now(orig_entry->orig_node); | ||
| 148 | kfree(orig_entry); | 153 | kfree(orig_entry); |
| 149 | } | 154 | } |
| 150 | 155 | ||