From: Li Zefan <lizefan@huawei•com>
To: David Miller <davem@davemloft•net>
Cc: <netdev@vger•kernel.org>, Gao feng <gaofeng@cn•fujitsu.com>,
John Fastabend <john.r.fastabend@intel•com>,
Neil Horman <nhorman@tuxdriver•com>
Subject: [PATCH 3.4.y 3/3] net: netprio: fix cgrp create and write priomap race
Date: Sat, 26 Jan 2013 12:42:22 +0800 [thread overview]
Message-ID: <51035EAE.5090004@huawei.com> (raw)
In-Reply-To: <51035E4F.6030508@huawei.com>
From: John Fastabend <john.r.fastabend@intel•com>
commit 476ad154f3b41dd7d9a08a2f641e28388abc2fd1 upstream.
A race exists where creating cgroups and also updating the priomap
may result in losing a priomap update. This is because priomap
writers are not protected by rtnl_lock.
Move priority writer into rtnl_lock()/rtnl_unlock().
CC: Neil Horman <nhorman@tuxdriver•com>
Reported-by: Al Viro <viro@ZenIV•linux.org.uk>
Signed-off-by: John Fastabend <john.r.fastabend@intel•com>
Acked-by: Neil Horman <nhorman@tuxdriver•com>
Signed-off-by: David S. Miller <davem@davemloft•net>
Signed-off-by: Li Zefan <lizefan@huawei•com>
---
net/core/netprio_cgroup.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index dca347e..eb07ea9 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -112,12 +112,10 @@ static int write_update_netdev_table(struct net_device *dev)
u32 max_len;
struct netprio_map *map;
- rtnl_lock();
max_len = atomic_read(&max_prioidx) + 1;
map = rtnl_dereference(dev->priomap);
if (!map || map->priomap_len < max_len)
ret = extend_netdev_table(dev, max_len);
- rtnl_unlock();
return ret;
}
@@ -267,17 +265,17 @@ static int write_priomap(struct cgroup *cgrp, struct cftype *cft,
if (!dev)
goto out_free_devname;
+ rtnl_lock();
ret = write_update_netdev_table(dev);
if (ret < 0)
goto out_put_dev;
- rcu_read_lock();
- map = rcu_dereference(dev->priomap);
+ map = rtnl_dereference(dev->priomap);
if (map)
map->priomap[prioidx] = priority;
- rcu_read_unlock();
out_put_dev:
+ rtnl_unlock();
dev_put(dev);
out_free_devname:
--
1.8.0.2
prev parent reply other threads:[~2013-01-26 4:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-26 4:40 [PATCH 3.4.y 0/3] netprio_cgroup: a few patches for stable tree Li Zefan
2013-01-26 4:41 ` [PATCH 3.4.y 1/3] cgroup: fix panic in netprio_cgroup Li Zefan
2013-01-26 4:41 ` [PATCH 3.4.y 2/3] net: cgroup: fix access the unallocated memory in netprio cgroup Li Zefan
2013-01-26 4:42 ` Li Zefan [this message]
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