** Description changed:

  [Impact]
   * libvirtd is no longer able to open the vhost_net device.  This causes the 
guest VM to hang.  This happens if memory becomes fragmented to the point where 
vhost_net_open is not able to successfully kmalloc.
  
   * Gratuitous stack trace.
  libvirtd: page allocation failure: order:4, mode:0x1040d0
  CPU: 14 PID: 82768 Comm: libvirtd Not tainted 3.13.0-85-generic #129-Ubuntu
  Hardware name: Dell Inc. PowerEdge R730/0599V5, BIOS 1.5.4 10/002/2015
   0000000000000000 ffff88003b419990 ffffffff8172b6a7 00000000001040d0
   0000000000000000 ffff88003b419a18 ffffffff811580eb ffff88187fffce48
   ffff88003b4199b8 ffffffff8115abd6 ffff88003b4199e8 0000000000000286
  Call Trace:
   [<ffffffff8172b6a7>] dump_stack+0x64/0x82
   [<ffffffff811580eb>] warn_alloc_failed+0xeb/0x140
   [<ffffffff8115abd6>] ? drain_local_pages+0x16/0x20
   [<ffffffff8115c8c0>] __alloc_pages_nodemask+0x980/0xb90
   [<ffffffff8119b3a3>] alloc_pages_current+0xa3/0x160
   [<ffffffff811570ae>] __get_free_pages+0xe/0x50
   [<ffffffff811743be>] kmalloc_order_trace+0x2e/0xc0
   [<ffffffffa04e79c9>] vhost_net_open+0x29/0x1b0 [vhost_net]
   [<ffffffff81484283>] misc_open+0xb3/0x170
   [<ffffffff811c63ff>] chrdev_open+0x9f/0x1d0
   [<ffffffff811bef13>] do_dentry_open+0x233/0x2e0
   [<ffffffff811c6360>] ? cdev_put+0x30/0x30
   [<ffffffff811bf249>] vfs_open+0x49/0x50
   [<ffffffff811d0812>] do_last+0x562/0x1370
   [<ffffffff811d16db>] path_openat+0xbb/0x670
   [<ffffffff811d2afa>] do_filp_open+0x3a/0x90
   [<ffffffff811df957>] ? __alloc_fd+0xa7/0x130
   [<ffffffff811c0d69>] do_sys_open+0x129/0x2a0
   [<ffffffff811c0efe>] SyS_open+0x1e/0x20
   [<ffffffff8173c39d>] system_call_fastpath+0x1a/0x1f
  
   * justification: because cloud.
  
   * The patches fix this issue by allowing vhost_net_open to use vmalloc
  when kmalloc fails to find a sufficient page size.
  
  [Test Case]
  
   * Fragment Kernel memory.  Write to Nic from within a kvm guest that
  uses a virtio nic.
  
  [Regression Potential]
  
   * Fix was implemented upstream in 3.15, and still exists.
  
-  * The fix is fairly straightfoward given the stack trace and the
+  * The fix is fairly straightfoward given the stack trace and the
  upstream fix.
  
   * The fix is hard to verify, as it requires significant memory
  fragmentation, and an over-active guest.  The users machine that was
  experiencing this has worked around this by removing VM's from the
  compute host, and using vfs.cache.pressure=600.
  
  [Other Info]
  
   * https://lkml.org/lkml/2013/1/23/492
   * 
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=23cc5a991c7a9fb7e6d6550e65cee4f4173111c5
   * 
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d04257b07f2362d4eb550952d5bf5f4241a8046d
-  * I'm going on vacation, and Eric Desrochers will be following up on this in 
my absence.  This is also the reason for submitting before receiving 
verification.
+  * I'm going on vacation, and Eric Desrochers will be following up on this in 
my absence.  This is also the reason for submitting before receiving 
verification.

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https://bugs.launchpad.net/bugs/1616193

Title:
  3.13: libvirtd: page allocation failure: order:4, mode:0x1040d0

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