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

    pktgen: fix crash at module unload

to the 3.0-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:
     pktgen-fix-crash-at-module-unload.patch
and it can be found in the queue-3.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From e36258658f4efc6c8a160839d0f7d3c987c10f7f Mon Sep 17 00:00:00 2001
From: Eric Dumazet <eric.duma...@gmail.com>
Date: Wed, 9 May 2012 13:29:51 +0000
Subject: pktgen: fix crash at module unload


From: Eric Dumazet <eric.duma...@gmail.com>

[ Upstream commit c57b54684060c8aced64a5b78ff69ff289af97b9 ]

commit 7d3d43dab4e9 (net: In unregister_netdevice_notifier unregister
the netdevices.) makes pktgen crashing at module unload.

[  296.820578] BUG: spinlock bad magic on CPU#6, rmmod/3267
[  296.820719]  lock: ffff880310c38000, .magic: ffff8803, .owner: <none>/-1, 
.owner_cpu: -1
[  296.820943] Pid: 3267, comm: rmmod Not tainted 3.4.0-rc5+ #254
[  296.821079] Call Trace:
[  296.821211]  [<ffffffff8168a715>] spin_dump+0x8a/0x8f
[  296.821345]  [<ffffffff8168a73b>] spin_bug+0x21/0x26
[  296.821507]  [<ffffffff812b4741>] do_raw_spin_lock+0x131/0x140
[  296.821648]  [<ffffffff8169188e>] _raw_spin_lock+0x1e/0x20
[  296.821786]  [<ffffffffa00cc0fd>] __pktgen_NN_threads+0x4d/0x140 [pktgen]
[  296.821928]  [<ffffffffa00ccf8d>] pktgen_device_event+0x10d/0x1e0 [pktgen]
[  296.822073]  [<ffffffff8154ed4f>] unregister_netdevice_notifier+0x7f/0x100
[  296.822216]  [<ffffffffa00d2a0b>] pg_cleanup+0x48/0x73 [pktgen]
[  296.822357]  [<ffffffff8109528e>] sys_delete_module+0x17e/0x2a0
[  296.822502]  [<ffffffff81699652>] system_call_fastpath+0x16/0x1b

Hold the pktgen_thread_lock while splicing pktgen_threads, and test
pktgen_exiting in pktgen_device_event() to make unload faster.

Signed-off-by: Eric Dumazet <eduma...@google.com>
Cc: Eric W. Biederman <ebied...@xmission.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/core/pktgen.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -1932,7 +1932,7 @@ static int pktgen_device_event(struct no
 {
        struct net_device *dev = ptr;
 
-       if (!net_eq(dev_net(dev), &init_net))
+       if (!net_eq(dev_net(dev), &init_net) || pktgen_exiting)
                return NOTIFY_DONE;
 
        /* It is OK that we do not hold the group lock right now,
@@ -3755,12 +3755,18 @@ static void __exit pg_cleanup(void)
 {
        struct pktgen_thread *t;
        struct list_head *q, *n;
+       struct list_head list;
 
        /* Stop all interfaces & threads */
        pktgen_exiting = true;
 
-       list_for_each_safe(q, n, &pktgen_threads) {
+       mutex_lock(&pktgen_thread_lock);
+       list_splice(&list, &pktgen_threads);
+       mutex_unlock(&pktgen_thread_lock);
+
+       list_for_each_safe(q, n, &list) {
                t = list_entry(q, struct pktgen_thread, th_list);
+               list_del(&t->th_list);
                kthread_stop(t->tsk);
                kfree(t);
        }


Patches currently in stable-queue which might be from eric.duma...@gmail.com are

queue-3.0/pktgen-fix-crash-at-module-unload.patch
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