Subject: Re: [virtio-net] BUG: sleeping function called from invalid context at kernel/mutex.c:616

From: Jason Wang <[email-masked]>
Date: Tue, 22 Oct 2013 16:35:32 +0800

On 10/20/2013 10:34 AM, Fengguang Wu wrote:
> Greetings,
>
> I got the below dmesg and the first bad commit is
>
> commit 3ab098df35f8b98b6553edc2e40234af512ba877
> Author: Jason Wang <[email-masked]>
> Date:   Tue Oct 15 11:18:58 2013 +0800
>
>     virtio-net: don't respond to cpu hotplug notifier if we're not ready
>     
>     We're trying to re-configure the affinity unconditionally in cpu hotplug
>     callback. This may lead the issue during resuming from s3/s4 since
>     
>     - virt queues haven't been allocated at that time.
>     - it's unnecessary since thaw method will re-configure the affinity.
>     
>     Fix this issue by checking the config_enable and do nothing is we're not ready.
>     
>     The bug were introduced by commit 8de4b2f3ae90c8fc0f17eeaab87d5a951b66ee17
>     (virtio-net: reset virtqueue affinity when doing cpu hotplug).
>     
>     Cc: Rusty Russell <[email-masked]>
>     Cc: Michael S. Tsirkin <[email-masked]>
>     Cc: Wanlong Gao <[email-masked]>
>     Acked-by: Michael S. Tsirkin <[email-masked]>
>     Reviewed-by: Wanlong Gao <[email-masked]>
>     Signed-off-by: Jason Wang <[email-masked]>
>     Signed-off-by: David S. Miller <[email-masked]>
>
> [  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]  [<ffffffff81a32f22>] dump_stack+0x54/0x74
> [  622.950815]  [<ffffffff810edb02>] __might_sleep+0x112/0x114
> [  622.950817]  [<ffffffff81a396ed>] mutex_lock_nested+0x3c/0x3c6
> [  622.950818]  [<ffffffff810e861d>] ? up+0x39/0x3e
> [  622.950821]  [<ffffffff8153ea7c>] ? acpi_os_signal_semaphore+0x21/0x2d
> [  622.950824]  [<ffffffff81565ed1>] ? acpi_ut_release_mutex+0x5e/0x62
> [  622.950828]  [<ffffffff816d04ec>] virtnet_cpu_callback+0x33/0x87
> [  622.950830]  [<ffffffff81a42576>] notifier_call_chain+0x3c/0x5e
> [  622.950832]  [<ffffffff810e86a8>] __raw_notifier_call_chain+0xe/0x10
> [  622.950835]  [<ffffffff810c5556>] __cpu_notify+0x20/0x37
> [  622.950836]  [<ffffffff810c5580>] cpu_notify+0x13/0x15
> [  622.950838]  [<ffffffff81a237cd>] take_cpu_down+0x27/0x3a
> [  622.950841]  [<ffffffff81136289>] stop_machine_cpu_stop+0x93/0xf1
> [  622.950842]  [<ffffffff81136167>] cpu_stopper_thread+0xa0/0x12f
> [  622.950844]  [<ffffffff811361f6>] ? cpu_stopper_thread+0x12f/0x12f
> [  622.950847]  [<ffffffff81119710>] ? lock_release_holdtime.part.7+0xa3/0xa8
> [  622.950848]  [<ffffffff81135e4b>] ? cpu_stop_should_run+0x3f/0x47
> [  622.950850]  [<ffffffff810ea9b0>] smpboot_thread_fn+0x1c5/0x1e3
> [  622.950852]  [<ffffffff810ea7eb>] ? lg_global_unlock+0x67/0x67
> [  622.950854]  [<ffffffff810e36b7>] kthread+0xd8/0xe0
> [  622.950857]  [<ffffffff81a3bfad>] ? wait_for_common+0x12f/0x164
> [  622.950859]  [<ffffffff810e35df>] ? kthread_create_on_node+0x124/0x124
> [  622.950861]  [<ffffffff81a45ffc>] ret_from_fork+0x7c/0xb0
> [  622.950862]  [<ffffffff810e35df>] ? 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
 
Thanks for the testing Fengguang, could you please try the attached
patch to see if it works?
>>From 01e6c3f71c202aa02e4feda169e7cc9fb24193f5 Mon Sep 17 00:00:00 2001
From: Jason Wang <[email-masked]>
Date: Mon, 21 Oct 2013 20:39:09 +0800
Subject: [PATCH] virtio-net: fix

---
 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 9fbdfcd..bbc9cb8 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
-- 
1.8.1.2

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