vmxnet3_reset_work() expects tx queues to be stopped (via
vmxnet3_quiesce_dev -> netif_tx_disable). However, this races with the
netif_wake_queue() call in netif_tx_timeout() such that the driver's
start_xmit routine may be called unexpectedly, triggering one of the BUG_ON
in vmxnet3_map_pkt with a stack trace like this:

RIP: 0010:[<ffffffffa00cf4bc>] vmxnet3_map_pkt+0x3ac/0x4c0 [vmxnet3]
 [<ffffffffa00cf7e0>] vmxnet3_tq_xmit+0x210/0x4e0 [vmxnet3]
 [<ffffffff813ab144>] dev_hard_start_xmit+0x2e4/0x4c0
 [<ffffffff813c956e>] sch_direct_xmit+0x17e/0x1e0
 [<ffffffff813c96a7>] __qdisc_run+0xd7/0x130
 [<ffffffff813a6a7a>] net_tx_action+0x10a/0x200
 [<ffffffff810691df>] __do_softirq+0x11f/0x260
 [<ffffffff81472fdc>] call_softirq+0x1c/0x30
 [<ffffffff81004695>] do_softirq+0x65/0xa0
 [<ffffffff81069b89>] local_bh_enable_ip+0x99/0xa0
 [<ffffffffa031ff36>] destroy_conntrack+0x96/0x110 [nf_conntrack]
 [<ffffffff813d65e2>] nf_conntrack_destroy+0x12/0x20
 [<ffffffff8139c6d5>] skb_release_head_state+0xb5/0xf0
 [<ffffffff8139d299>] skb_release_all+0x9/0x20
 [<ffffffff8139cfe9>] __kfree_skb+0x9/0x90
 [<ffffffffa00d0069>] vmxnet3_quiesce_dev+0x209/0x340 [vmxnet3]
 [<ffffffffa00d020a>] vmxnet3_reset_work+0x6a/0xa0 [vmxnet3]
 [<ffffffff8107d7cc>] process_one_work+0x16c/0x350
 [<ffffffff810804fa>] worker_thread+0x17a/0x410
 [<ffffffff810848c6>] kthread+0x96/0xa0
 [<ffffffff81472ee4>] kernel_thread_helper+0x4/0x10
Signed-off-by: NBenjamin Poirier <bpoirier@suse.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>