netlink: use kfree_rcu() in netlink_release()
authorEric Dumazet <edumazet@google.com>
Thu, 18 Oct 2012 03:21:55 +0000 (03:21 +0000)
committerBen Hutchings <ben@decadent.org.uk>
Fri, 16 Nov 2012 16:47:15 +0000 (16:47 +0000)
commit9e4ac2075cbf126be9e37762c8c1c6aec714dcc5
treed9bffc59ec9a5438ad73c94c616c62b4b42e6080
parentde77b7955c3985ca95f64af3cb10557eb17eacee
netlink: use kfree_rcu() in netlink_release()

[ Upstream commit 6d772ac5578f711d1ce7b03535d1c95bffb21dff ]

On some suspend/resume operations involving wimax device, we have
noticed some intermittent memory corruptions in netlink code.

St├ęphane Marchesin tracked this corruption in netlink_update_listeners()
and suggested a patch.

It appears netlink_release() should use kfree_rcu() instead of kfree()
for the listeners structure as it may be used by other cpus using RCU
protection.

netlink_release() must set to NULL the listeners pointer when
it is about to be freed.

Also have to protect netlink_update_listeners() and
netlink_has_listeners() if listeners is NULL.

Add a nl_deref_protected() lockdep helper to properly document which
locks protects us.

Reported-by: Jonathan Kliegman <kliegs@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: St├ęphane Marchesin <marcheu@google.com>
Cc: Sam Leffler <sleffler@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
net/netlink/af_netlink.c