diff options
| author | Marek Lindner <lindner_marek@yahoo.de> | 2011-02-18 12:28:10 +0000 |
|---|---|---|
| committer | Marek Lindner <lindner_marek@yahoo.de> | 2011-03-05 12:52:01 +0100 |
| commit | 7b36e8eef989fc59535b4f1d3fc0f83afaf419d4 (patch) | |
| tree | f0900101542966e0655ca5f115b5b0bc409b1e74 /net/batman-adv/gateway_client.c | |
| parent | 7aadf889e897155c45cda230d2a6701ad1fbff61 (diff) | |
| download | linux-7b36e8eef989fc59535b4f1d3fc0f83afaf419d4.tar.bz2 | |
batman-adv: Correct rcu refcounting for orig_node
It might be possible that 2 threads access the same data in the same
rcu grace period. The first thread calls call_rcu() to decrement the
refcount and free the data while the second thread increases the
refcount to use the data. To avoid this race condition all refcount
operations have to be atomic.
Reported-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
Diffstat (limited to 'net/batman-adv/gateway_client.c')
| -rw-r--r-- | net/batman-adv/gateway_client.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c index 41eba8a660f5..3cc43558cf9c 100644 --- a/net/batman-adv/gateway_client.c +++ b/net/batman-adv/gateway_client.c @@ -53,9 +53,11 @@ void *gw_get_selected(struct bat_priv *bat_priv) goto out; orig_node = curr_gateway_tmp->orig_node; + if (!orig_node) + goto out; - if (orig_node) - kref_get(&orig_node->refcount); + if (!atomic_inc_not_zero(&orig_node->refcount)) + orig_node = NULL; out: rcu_read_unlock(); |