From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120607041403.048334284@linuxfoundation.org> Date: Thu, 07 Jun 2012 13:14:32 +0900 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Eric Dumazet , "Eric W. Biederman" , "David S. Miller" Subject: [ 34/47] pktgen: fix crash at module unload In-Reply-To: <20120607041504.GA13819@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ 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: /-1, .owner_cpu: -1 [ 296.820943] Pid: 3267, comm: rmmod Not tainted 3.4.0-rc5+ #254 [ 296.821079] Call Trace: [ 296.821211] [] spin_dump+0x8a/0x8f [ 296.821345] [] spin_bug+0x21/0x26 [ 296.821507] [] do_raw_spin_lock+0x131/0x140 [ 296.821648] [] _raw_spin_lock+0x1e/0x20 [ 296.821786] [] __pktgen_NN_threads+0x4d/0x140 [pktgen] [ 296.821928] [] pktgen_device_event+0x10d/0x1e0 [pktgen] [ 296.822073] [] unregister_netdevice_notifier+0x7f/0x100 [ 296.822216] [] pg_cleanup+0x48/0x73 [pktgen] [ 296.822357] [] sys_delete_module+0x17e/0x2a0 [ 296.822502] [] 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 Cc: Eric W. Biederman Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- 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); }