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authorEric Dumazet <eric.dumazet@gmail.com>2011-01-26 18:08:02 +0000
committerDavid S. Miller <davem@davemloft.net>2011-01-27 15:02:56 -0800
commitccf434380d1a67df2dcb9113206b77d0cb0a1cef (patch)
tree1e1a36691f42ed7448f27f71a9ca9445e88ab5f1 /net/core
parent065825402c058f4a123ddc53dbbe864cc5caaf64 (diff)
downloadop-kernel-dev-ccf434380d1a67df2dcb9113206b77d0cb0a1cef.zip
op-kernel-dev-ccf434380d1a67df2dcb9113206b77d0cb0a1cef.tar.gz
net: fix dev_seq_next()
Commit c6d14c84566d (net: Introduce for_each_netdev_rcu() iterator) added a race in dev_seq_next(). The rcu_dereference() call should be done _before_ testing the end of list, or we might return a wrong net_device if a concurrent thread changes net_device list under us. Note : discovered thanks to a sparse warning : net/core/dev.c:3919:9: error: incompatible types in comparison expression (different address spaces) Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> CC: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/dev.c11
1 files changed, 7 insertions, 4 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 1b4c07f..ddd5df2 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4051,12 +4051,15 @@ void *dev_seq_start(struct seq_file *seq, loff_t *pos)
void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
- struct net_device *dev = (v == SEQ_START_TOKEN) ?
- first_net_device(seq_file_net(seq)) :
- next_net_device((struct net_device *)v);
+ struct net_device *dev = v;
+
+ if (v == SEQ_START_TOKEN)
+ dev = first_net_device_rcu(seq_file_net(seq));
+ else
+ dev = next_net_device_rcu(dev);
++*pos;
- return rcu_dereference(dev);
+ return dev;
}
void dev_seq_stop(struct seq_file *seq, void *v)
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