Comment 2 for bug 856293

This looks a bit suspect to me:
Sep 22 12:26:39 ac100 AptDaemon.Worker: INFO: Upgrade system with safe mode: 1
Sep 22 12:27:28 ac100 kernel: [ 194.092879] kworker/u:2: page allocation failure. order:1, mode:0x4020
Sep 22 12:27:28 ac100 kernel: [ 194.092921] Backtrace:
Sep 22 12:27:28 ac100 kernel: [ 194.093049] [<c00427d0>] (unwind_backtrace+0x0/0xe0) from [<c00e29dc>] (__alloc_pages_nodemask+0x5c0/0x6dc)
Sep 22 12:27:28 ac100 kernel: [ 194.093168] [<c00e29dc>] (__alloc_pages_nodemask+0x5c0/0x6dc) from [<c0108908>] (allocate_slab+0x54/0xa8)
Sep 22 12:27:28 ac100 kernel: [ 194.093337] [<c0108908>] (allocate_slab+0x54/0xa8) from [<c0109d74>] (new_slab+0x2c/0x13c)
Sep 22 12:27:28 ac100 kernel: [ 194.093510] [<c0109d74>] (new_slab+0x2c/0x13c) from [<c04048ec>] (__slab_alloc.constprop.48+0x140/0x2c8)
Sep 22 12:27:28 ac100 kernel: [ 194.093687] [<c04048ec>] (__slab_alloc.constprop.48+0x140/0x2c8) from [<c010bbb0>] (__kmalloc_track_caller+0xa0/0x18c)
Sep 22 12:27:28 ac100 kernel: [ 194.093828] [<c010bbb0>] (__kmalloc_track_caller+0xa0/0x18c) from [<c0332d50>] (__alloc_skb+0x50/0xe0)
Sep 22 12:27:28 ac100 kernel: [ 194.093911] [<c0332d50>] (__alloc_skb+0x50/0xe0) from [<c0332df8>] (dev_alloc_skb+0x18/0x3c)
Sep 22 12:27:28 ac100 kernel: [ 194.094072] [<c0332df8>] (dev_alloc_skb+0x18/0x3c) from [<bf38b320>] (rt2x00queue_alloc_rxskb+0x40/0xb4 [rt2x00lib])
Sep 22 12:27:28 ac100 kernel: [ 194.094336] [<bf38b320>] (rt2x00queue_alloc_rxskb+0x40/0xb4 [rt2x00lib]) from [<bf388834>] (rt2x00lib_rxdone+0x3c/0x1bc [rt2x00lib])
Sep 22 12:27:28 ac100 kernel: [ 194.094582] [<bf388834>] (rt2x00lib_rxdone+0x3c/0x1bc [rt2x00lib]) from [<bf3bd4f8>] (rt2x00usb_work_rxdone+0x58/0x8c [rt2x00usb])
Sep 22 12:27:28 ac100 kernel: [ 194.094754] [<bf3bd4f8>] (rt2x00usb_work_rxdone+0x58/0x8c [rt2x00usb]) from [<c0087ce8>] (process_one_work+0x270/0x464)
Sep 22 12:27:28 ac100 kernel: [ 194.094852] [<c0087ce8>] (process_one_work+0x270/0x464) from [<c00881c0>] (worker_thread+0x134/0x230)
Sep 22 12:27:28 ac100 kernel: [ 194.095031] [<c00881c0>] (worker_thread+0x134/0x230) from [<c008c1a4>] (kthread+0x7c/0x84)
Sep 22 12:27:28 ac100 kernel: [ 194.095129] [<c008c1a4>] (kthread+0x7c/0x84) from [<c003c408>] (kernel_thread_exit+0x0/0x8)