From ec9debbd9a88d8ea86c488d6ffcac419ee7d46d9 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Tue, 29 Oct 2013 15:11:07 +0800 Subject: [PATCH] virtio-net: correctly handle cpu hotplug notifier during resuming commit 3ab098df35f8b98b6553edc2e40234af512ba877 (virtio-net: don't respond to cpu hotplug notifier if we're not ready) tries to bypass the cpu hotplug notifier by checking the config_enable and does nothing is it was false. So it need to try to hold the config_lock mutex which may happen in atomic environment which leads the following warnings: [ 622.944441] CPU0 attaching NULL sched-domain. [ 622.944446] CPU1 attaching NULL sched-domain. [ 622.944485] CPU0 attaching NULL sched-domain. [ 622.950795] BUG: sleeping function called from invalid context at kernel/mutex.c:616 [ 622.950796] in_atomic(): 1, irqs_disabled(): 1, pid: 10, name: migration/1 [ 622.950796] no locks held by migration/1/10. [ 622.950798] CPU: 1 PID: 10 Comm: migration/1 Not tainted 3.12.0-rc5-wl-01249-gb91e82d #317 [ 622.950799] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 622.950802] 0000000000000000 ffff88001d42dba0 ffffffff81a32f22 ffff88001bfb9c70 [ 622.950803] ffff88001d42dbb0 ffffffff810edb02 ffff88001d42dc38 ffffffff81a396ed [ 622.950805] 0000000000000046 ffff88001d42dbe8 ffffffff810e861d 0000000000000000 [ 622.950805] Call Trace: [ 622.950810] [] dump_stack+0x54/0x74 [ 622.950815] [] __might_sleep+0x112/0x114 [ 622.950817] [] mutex_lock_nested+0x3c/0x3c6 [ 622.950818] [] ? up+0x39/0x3e [ 622.950821] [] ? acpi_os_signal_semaphore+0x21/0x2d [ 622.950824] [] ? acpi_ut_release_mutex+0x5e/0x62 [ 622.950828] [] virtnet_cpu_callback+0x33/0x87 [ 622.950830] [] notifier_call_chain+0x3c/0x5e [ 622.950832] [] __raw_notifier_call_chain+0xe/0x10 [ 622.950835] [] __cpu_notify+0x20/0x37 [ 622.950836] [] cpu_notify+0x13/0x15 [ 622.950838] [] take_cpu_down+0x27/0x3a [ 622.950841] [] stop_machine_cpu_stop+0x93/0xf1 [ 622.950842] [] cpu_stopper_thread+0xa0/0x12f [ 622.950844] [] ? cpu_stopper_thread+0x12f/0x12f [ 622.950847] [] ? lock_release_holdtime.part.7+0xa3/0xa8 [ 622.950848] [] ? cpu_stop_should_run+0x3f/0x47 [ 622.950850] [] smpboot_thread_fn+0x1c5/0x1e3 [ 622.950852] [] ? lg_global_unlock+0x67/0x67 [ 622.950854] [] kthread+0xd8/0xe0 [ 622.950857] [] ? wait_for_common+0x12f/0x164 [ 622.950859] [] ? kthread_create_on_node+0x124/0x124 [ 622.950861] [] ret_from_fork+0x7c/0xb0 [ 622.950862] [] ? kthread_create_on_node+0x124/0x124 [ 622.950876] smpboot: CPU 1 is now offline [ 623.194556] SMP alternatives: lockdep: fixing up alternatives [ 623.194559] smpboot: Booting Node 0 Processor 1 APIC 0x1 ... A correct fix is to unregister the hotcpu notifier during restore and register a new one in resume. Reported-by: Fengguang Wu Tested-by: Fengguang Wu Cc: Wanlong Gao Cc: Rusty Russell Cc: Michael S. Tsirkin Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Reviewed-by: Wanlong Gao Signed-off-by: David S. Miller --- drivers/net/virtio_net.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 9fbdfcd1e1a0..bbc9cb84ec1f 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -1118,11 +1118,6 @@ static int virtnet_cpu_callback(struct notifier_block *nfb, { struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb); - mutex_lock(&vi->config_lock); - - if (!vi->config_enable) - goto done; - switch(action & ~CPU_TASKS_FROZEN) { case CPU_ONLINE: case CPU_DOWN_FAILED: @@ -1136,8 +1131,6 @@ static int virtnet_cpu_callback(struct notifier_block *nfb, break; } -done: - mutex_unlock(&vi->config_lock); return NOTIFY_OK; } @@ -1699,6 +1692,8 @@ static int virtnet_freeze(struct virtio_device *vdev) struct virtnet_info *vi = vdev->priv; int i; + unregister_hotcpu_notifier(&vi->nb); + /* Prevent config work handler from accessing the device */ mutex_lock(&vi->config_lock); vi->config_enable = false; @@ -1747,6 +1742,10 @@ static int virtnet_restore(struct virtio_device *vdev) virtnet_set_queues(vi, vi->curr_queue_pairs); rtnl_unlock(); + err = register_hotcpu_notifier(&vi->nb); + if (err) + return err; + return 0; } #endif -- 2.20.1