Patch "xfrm: policy: init locks early" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

xfrm: policy: init locks early

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
xfrm-policy-init-locks-early.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Florian Westphal <[email protected]>
Date: Wed, 8 Feb 2017 11:52:29 +0100
Subject: xfrm: policy: init locks early

From: Florian Westphal <[email protected]>

commit c282222a45cb9503cbfbebfdb60491f06ae84b49 upstream.

Dmitry reports following splat:
INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.

 CPU: 0 PID: 13059 Comm: syz-executor1 Not tainted 4.10.0-rc7-next-20170207 #1
[..]
 spin_lock_bh include/linux/spinlock.h:304 [inline]
 xfrm_policy_flush+0x32/0x470 net/xfrm/xfrm_policy.c:963
 xfrm_policy_fini+0xbf/0x560 net/xfrm/xfrm_policy.c:3041
 xfrm_net_init+0x79f/0x9e0 net/xfrm/xfrm_policy.c:3091
 ops_init+0x10a/0x530 net/core/net_namespace.c:115
 setup_net+0x2ed/0x690 net/core/net_namespace.c:291
 copy_net_ns+0x26c/0x530 net/core/net_namespace.c:396
 create_new_namespaces+0x409/0x860 kernel/nsproxy.c:106
 unshare_nsproxy_namespaces+0xae/0x1e0 kernel/nsproxy.c:205
 SYSC_unshare kernel/fork.c:2281 [inline]

Problem is that when we get error during xfrm_net_init we will call xfrm_policy_fini which will acquire xfrm_policy_lock before it was initialized. Just move it around so locks get set up first.

---
 net/xfrm/xfrm_policy.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

@@ -3062,6 +3062,11 @@ static int __net_init xfrm_net_init(stru
 {
 	int rv;
 
+	/* Initialize the per-net locks here */
+	spin_lock_init(&net->xfrm.xfrm_state_lock);
+	spin_lock_init(&net->xfrm.xfrm_policy_lock);
+	mutex_init(&net->xfrm.xfrm_cfg_mutex);
+
 	rv = xfrm_statistics_init(net);
 	if (rv < 0)
 		goto out_statistics;

@@ -3078,11 +3083,6 @@ static int __net_init xfrm_net_init(stru
 	if (rv < 0)
 		goto out;
 
-	/* Initialize the per-net locks here */
-	spin_lock_init(&net->xfrm.xfrm_state_lock);
-	spin_lock_init(&net->xfrm.xfrm_policy_lock);
-	mutex_init(&net->xfrm.xfrm_cfg_mutex);
-
 	return 0;
 
 out:

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/xfrm-policy-init-locks-early.patch