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  1. Dec 20, 2016
    • Vitaly Kuznetsov's avatar
      x86/hyperv: Handle unknown NMIs on one CPU when unknown_nmi_panic · 59107e2f
      Vitaly Kuznetsov authored 
      

There is a feature in Hyper-V ('Debug-VM --InjectNonMaskableInterrupt')
which injects NMI to the guest. We may want to crash the guest and do kdump
on this NMI by enabling unknown_nmi_panic. To make kdump succeed we need to
allow the kdump kernel to re-establish VMBus connection so it will see
VMBus devices (storage, network,..).

To properly unload VMBus making it possible to start over during kdump we
need to do the following:

 - Send an 'unload' message to the hypervisor. This can be done on any CPU
   so we do this the crashing CPU.

 - Receive the 'unload finished' reply message. WS2012R2 delivers this
   message to the CPU which was used to establish VMBus connection during
   module load and this CPU may differ from the CPU sending 'unload'.

Receiving a VMBus message means the following:

 - There is a per-CPU slot in memory for one message. This slot can in
   theory be accessed by any CPU.

 - We get an interrupt on the CPU when a message was placed into the slot.

 - When we read the message we need to clear the slot and signal the fact
   to the hypervisor. In case there are more messages to this CPU pending
   the hypervisor will deliver the next message. The signaling is done by
   writing to an MSR so this can only be done on the appropriate CPU.

To avoid doing cross-CPU work on crash we have vmbus_wait_for_unload()
function which checks message slots for all CPUs in a loop waiting for the
'unload finished' messages. However, there is an issue which arises when
these conditions are met:

 - We're crashing on a CPU which is different from the one which was used
   to initially contact the hypervisor.

 - The CPU which was used for the initial contact is blocked with interrupts
   disabled and there is a message pending in the message slot.

In this case we won't be able to read the 'unload finished' message on the
crashing CPU. This is reproducible when we receive unknown NMIs on all CPUs
simultaneously: the first CPU entering panic() will proceed to crash and
all other CPUs will stop themselves with interrupts disabled.

The suggested solution is to handle unknown NMIs for Hyper-V guests on the
first CPU which gets them only. This will allow us to rely on VMBus
interrupt handler being able to receive the 'unload finish' message in
case it is delivered to a different CPU.

The issue is not reproducible on WS2016 as Debug-VM delivers NMI to the
boot CPU only, WS2012R2 and earlier Hyper-V versions are affected.

Signed-off-by: default avatarVitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Cc: devel@linuxdriverproject.org
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Link: http://lkml.kernel.org/r/20161202100720.28121-1-vkuznets@redhat.com


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      59107e2f
  3. Dec 19, 2016
  5. Dec 18, 2016
    • Thomas Gleixner's avatar
      x86/tsc: Limit the adjust value further · 8c9b9d87
      Thomas Gleixner authored 
      

Adjust value 0x80000000 and other values larger than that render the TSC
deadline timer disfunctional.

We have not yet any information about this from Intel, but experimentation
clearly proves that this is a 32/64 bit and sign extension issue.

If adjust values larger than that are actually required, which might be the
case for physical CPU hotplug, then we need to disable the deadline timer
on the affected package/CPUs and use the local APIC timer instead.

That requires some surgery in the APIC setup code, so we just limit the
ADJUST register value into the known to work range for now and revisit this
when Intel comes forth with proper information.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Roland Scheidegger <rscheidegger_lists@hispeed.ch>
Cc: Bruce Schlobohm <bruce.schlobohm@intel.com>
Cc: Kevin Stanton <kevin.b.stanton@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
      8c9b9d87
    • Thomas Gleixner's avatar
      x86/tsc: Annotate printouts as firmware bug · 16588f65
      Thomas Gleixner authored 
      

Make it more obvious that the BIOS is screwed up.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Roland Scheidegger <rscheidegger_lists@hispeed.ch>
Cc: Bruce Schlobohm <bruce.schlobohm@intel.com>
Cc: Kevin Stanton <kevin.b.stanton@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
      16588f65
    • Kees Cook's avatar
      x86/floppy: Use designated initializers · ffc7dc8d
      Kees Cook authored 
      

Prepare to mark sensitive kernel structures for randomization by making
sure they're using designated initializers. These were identified during
allyesconfig builds of x86, arm, and arm64, with most initializer fixes
extracted from grsecurity.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161217213705.GA1248@beast


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      ffc7dc8d
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net · 52f40e9d
      Linus Torvalds authored 
      Pull networking fixes and cleanups from David Miller:

 1) Revert bogus nla_ok() change, from Alexey Dobriyan.

 2) Various bpf validator fixes from Daniel Borkmann.

 3) Add some necessary SET_NETDEV_DEV() calls to hsis_femac and hip04
    drivers, from Dongpo Li.

 4) Several ethtool ksettings conversions from Philippe Reynes.

 5) Fix bugs in inet port management wrt. soreuseport, from Tom Herbert.

 6) XDP support for virtio_net, from John Fastabend.

 7) Fix NAT handling within a vrf, from David Ahern.

 8) Endianness fixes in dpaa_eth driver, from Claudiu Manoil

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (63 commits)
  net: mv643xx_eth: fix build failure
  isdn: Constify some function parameters
  mlxsw: spectrum: Mark split ports as such
  cgroup: Fix CGROUP_BPF config
  qed: fix old-style function definition
  net: ipv6: check route protocol when deleting routes
  r6040: move spinlock in r6040_close as SOFTIRQ-unsafe lock order detected
  irda: w83977af_ir: cleanup an indent issue
  net: sfc: use new api ethtool_{get|set}_link_ksettings
  net: davicom: dm9000: use new api ethtool_{get|set}_link_ksettings
  net: cirrus: ep93xx: use new api ethtool_{get|set}_link_ksettings
  net: chelsio: cxgb3: use new api ethtool_{get|set}_link_ksettings
  net: chelsio: cxgb2: use new api ethtool_{get|set}_link_ksettings
  bpf: fix mark_reg_unknown_value for spilled regs on map value marking
  bpf: fix overflow in prog accounting
  bpf: dynamically allocate digest scratch buffer
  gtp: Fix initialization of Flags octet in GTPv1 header
  gtp: gtp_check_src_ms_ipv4() always return success
  net/x25: use designated initializers
  isdn: use designated initializers
  ...
      52f40e9d
    • Linus Torvalds's avatar
      Merge uncontroversial parts of branch 'readlink' of... · 231753ef
      Linus Torvalds authored 
      Merge uncontroversial parts of branch 'readlink' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull partial readlink cleanups from Miklos Szeredi.

This is the uncontroversial part of the readlink cleanup patch-set that
simplifies the default readlink handling.

Miklos and Al are still discussing the rest of the series.

* git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  vfs: make generic_readlink() static
  vfs: remove ".readlink = generic_readlink" assignments
  vfs: default to generic_readlink()
  vfs: replace calling i_op->readlink with vfs_readlink()
  proc/self: use generic_readlink
  ecryptfs: use vfs_get_link()
  bad_inode: add missing i_op initializers
      231753ef