Xenial update to 4.4.142 stable release

[Stefan Bader]

SRU Justification

    Impact:
       The upstream process for stable tree updates is quite similar
       in scope to the Ubuntu SRU process, e.g., each patch has to
       demonstrably fix a bug, and each patch is vetted by upstream
       by originating either directly from a mainline/stable Linux tree or
       a minimally backported form of that patch. The 4.4.142 upstream stable
       patch set is now available. It should be included in the Ubuntu
       kernel as well.

       git://git.kernel.org/

    TEST CASE: TBD

The following patches from the 4.4.142 stable release shall be applied:
* Kbuild: fix # escaping in .cmd files for future Make
* perf tools: Move syscall number fallbacks from perf-sys.h to
  tools/arch/x86/include/asm/
* Linux 4.4.142

[Stefan Bader (smb)]

Skipped "x86/cpu: Probe CPUID leaf 6 even when cpuid_level == 6" because this is already correctly done in the Xenial tree.

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 4.4.0-137.163

---------------
linux (4.4.0-137.163) xenial; urgency=medium

  * CVE-2018-14633
    - iscsi target: Use hex2bin instead of a re-implementation

  * CVE-2018-17182
    - mm: get rid of vmacache_flush_all() entirely

linux (4.4.0-136.162) xenial; urgency=medium

  * linux: 4.4.0-136.162 -proposed tracker (LP: #1791745)

  * CVE-2017-5753
    - bpf: properly enforce index mask to prevent out-of-bounds speculation
    - Revert "UBUNTU: SAUCE: bpf: Use barrier_nospec() instead of osb()"
    - Revert "bpf: prevent speculative execution in eBPF interpreter"

  * L1TF mitigation not effective in some CPU and RAM combinations
    (LP: #1788563) // CVE-2018-3620 // CVE-2018-3646
    - x86/speculation/l1tf: Fix overflow in l1tf_pfn_limit() on 32bit
    - x86/speculation/l1tf: Fix off-by-one error when warning that system has too
      much RAM
    - x86/speculation/l1tf: Increase l1tf memory limit for Nehalem+

  * CVE-2018-15594
    - x86/paravirt: Fix spectre-v2 mitigations for paravirt guests

  * Xenial update to 4.4.144 stable release (LP: #1791080)
    - KVM/Eventfd: Avoid crash when assign and deassign specific eventfd in
      parallel.
    - x86/MCE: Remove min interval polling limitation
    - fat: fix memory allocation failure handling of match_strdup()
    - ALSA: rawmidi: Change resized buffers atomically
    - ARC: Fix CONFIG_SWAP
    - ARC: mm: allow mprotect to make stack mappings executable
    - mm: memcg: fix use after free in mem_cgroup_iter()
    - ipv4: Return EINVAL when ping_group_range sysctl doesn't map to user ns
    - ipv6: fix useless rol32 call on hash
    - lib/rhashtable: consider param->min_size when setting initial table size
    - net/ipv4: Set oif in fib_compute_spec_dst
    - net: phy: fix flag masking in __set_phy_supported
    - ptp: fix missing break in switch
    - tg3: Add higher cpu clock for 5762.
    - net: Don't copy pfmemalloc flag in __copy_skb_header()
    - skbuff: Unconditionally copy pfmemalloc in __skb_clone()
    - xhci: Fix perceived dead host due to runtime suspend race with event handler
    - x86/paravirt: Make native_save_fl() extern inline
    - SAUCE: Add missing CPUID_7_EDX defines
    - SAUCE: x86/speculation: Expose indirect_branch_prediction_barrier()
    - x86/pti: Mark constant arrays as __initconst
    - x86/asm/entry/32: Simplify pushes of zeroed pt_regs->REGs
    - x86/entry/64/compat: Clear registers for compat syscalls, to reduce
      speculation attack surface
    - x86/speculation: Clean up various Spectre related details
    - x86/speculation: Fix up array_index_nospec_mask() asm constraint
    - x86/xen: Zero MSR_IA32_SPEC_CTRL before suspend
    - x86/mm: Factor out LDT init from context init
    - x86/mm: Give each mm TLB flush generation a unique ID
    - SAUCE: x86/speculation: Use Indirect Branch Prediction Barrier in context
      switch
    - x86/speculation: Use IBRS if available before calling into firmware
    - x86/speculation: Move firmware_restrict_branch_speculation_*() from C to CPP
    - selftest/seccomp: Fix the seccomp(2) signature
    - xen: set cpu capabilities from xen_start_kernel()
    - x86/amd: d...