Messages in this thread | | | Date | Tue, 14 Jul 2015 11:38:25 +0200 | From | Thomas Graf <> | Subject | Re: mmap()ed AF_NETLINK: lockdep and sleep-in-atomic warnings |
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On 07/13/15 at 10:11pm, Cong Wang wrote: > Caused by: > > commit 21e4902aea80ef35afc00ee8d2abdea4f519b7f7 > Author: Thomas Graf <tgraf@suug.ch> > Date: Fri Jan 2 23:00:22 2015 +0100 > > netlink: Lockless lookup with RCU grace period in socket release > > Defers the release of the socket reference using call_rcu() to > allow using an RCU read-side protected call to rhashtable_lookup() > > This restores behaviour and performance gains as previously > introduced by e341694 ("netlink: Convert netlink_lookup() to use > RCU protected hash table") without the side effect of severely > delayed socket destruction. > > Signed-off-by: Thomas Graf <tgraf@suug.ch> > Signed-off-by: David S. Miller <davem@davemloft.net> > > > We can't hold mutex lock in a rcu callback, perhaps we could > defer the mmap ring cleanup to a workqueue.
The socket should be dead at this point. It might be simpler to add a netlink_release_ring() function which doesn't require locking at all. It would also get rid of all the special handling for closing vs. non-closing.
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