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| author |   Florian Westphal <fw@strlen.de> | 2017-08-10 16:52:59 +0200 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2017-08-10 09:50:22 -0700 |
| commit | 8515ae38435895ba2862840d3e82140fc0a77554 (patch) | |
| tree | b7b2cd7e34d56bceb4c53d8058f81d6a3bf1748d /net/core/rtnetlink.c | |
| parent | rtnetlink: do not use RTM_GETLINK directly (diff) | |
| download | linux-dev-8515ae38435895ba2862840d3e82140fc0a77554.tar.xz linux-dev-8515ae38435895ba2862840d3e82140fc0a77554.zip | |
rtnetlink: switch rtnl_link_get_slave_info_data_size to rcu
David Ahern reports following splat:
RTNL: assertion failed at net/core/dev.c (5717)
netdev_master_upper_dev_get+0x5f/0x70
if_nlmsg_size+0x158/0x240
rtnl_calcit.isra.26+0xa3/0xf0
rtnl_link_get_slave_info_data_size currently assumes RTNL protection, but
there appears to be no hard requirement for this, so use rcu instead.
At the time of this writing, there are three 'get_slave_size' callbacks
(now invoked under rcu): bond_get_slave_size, vrf_get_slave_size and
br_port_get_slave_size, all return constant only (i.e. they don't sleep).
Fixes: 6853dd488119 ("rtnetlink: protect handler table with rcu")
Reported-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/rtnetlink.c')
| -rw-r--r-- | net/core/rtnetlink.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index a9b5ebc1af21..087f2434813a 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -402,16 +402,24 @@ static size_t rtnl_link_get_slave_info_data_size(const struct net_device *dev) { struct net_device *master_dev; const struct rtnl_link_ops *ops; + size_t size = 0; - master_dev = netdev_master_upper_dev_get((struct net_device *) dev); + rcu_read_lock(); + + master_dev = netdev_master_upper_dev_get_rcu((struct net_device *)dev); if (!master_dev) - return 0; + goto out; + ops = master_dev->rtnl_link_ops; if (!ops || !ops->get_slave_size) - return 0; + goto out; /* IFLA_INFO_SLAVE_DATA + nested data */ - return nla_total_size(sizeof(struct nlattr)) + + size = nla_total_size(sizeof(struct nlattr)) + ops->get_slave_size(master_dev, dev); + +out: + rcu_read_unlock(); + return size; } static size_t rtnl_link_get_size(const struct net_device *dev) |