System hang when plug/pull USB 3.1 key via thunderbolt port over 5 times

This commit can fix this issue

commit ab2a4bf83902c170d29ba130a8abb5f9d90559e1
Author: Alan Stern <email address hidden>
Date: Mon Jun 27 10:23:10 2016 -0400

    USB: don't free bandwidth_mutex too early

    The USB core contains a bug that can show up when a USB-3 host
    controller is removed. If the primary (USB-2) hcd structure is
    released before the shared (USB-3) hcd, the core will try to do a
    double-free of the common bandwidth_mutex.

    The problem was described in graphical form by Chung-Geol Kim, who
    first reported it:

    =================================================
         At *remove USB(3.0) Storage
         sequence <1> --> <5> ((Problem Case))
    =================================================
                                      VOLD
    ------------------------------------|------------
                                     (uevent)
                                ________|_________
                               |<1> |
                               |dwc3_otg_sm_work |
                               |usb_put_hcd |
                               |peer_hcd(kref=2)|
                               |__________________|
                                ________|_________
                               |<2> |
                               |New USB BUS #2 |
                               | |
                               |peer_hcd(kref=1) |
                               | |
                             --(Link)-bandXX_mutex|
                             | |__________________|
                             |
        ___________________ |
       |<3> | |
       |dwc3_otg_sm_work | |
       |usb_put_hcd | |
       |primary_hcd(kref=1)| |
       |___________________| |
        _________|_________ |
       |<4> | |
       |New USB BUS #1 | |
       |hcd_release | |
       |primary_hcd(kref=0)| |
       | | |
       |bandXX_mutex(free) |<-
       |___________________|
                                   (( VOLD ))
                                ______|___________
                               |<5> |
                               | SCSI |
                               |usb_put_hcd |
                               |peer_hcd(kref=0) |
                               |*hcd_release |
                               |bandXX_mutex(free*)|<- double free
                               |__________________|

    =================================================

    This happens because hcd_release() frees the bandwidth_mutex whenever
    it sees a primary hcd being released (which is not a very good idea
    in any case), but in the course of releasing the primary hcd, it
    changes the pointers in the shared hcd in such a way that the shared
    hcd will appear to be primary when it gets released.

    This patch fixes the problem by changing hcd_release() so that it
    deallocates the bandwidth_mutex only when the _last_ hcd structure
    referencing it is released. The patch also removes an unnecessary
  ...

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-xenial' to 'verification-done-xenial'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

With kernel 4.4.0-38.57, I can't reproduce this issue.

This bug was fixed in the package linux - 4.4.0-38.57

---------------
linux (4.4.0-38.57) xenial; urgency=low

  [ Tim Gardner ]

  * Release Tracking Bug
    - LP: #1620658

  * CIFS client: access problems after updating to kernel 4.4.0-29-generic
    (LP: #1612135)
    - Revert "UBUNTU: SAUCE: (namespace) Bypass sget() capability check for nfs"
    - fs: Call d_automount with the filesystems creds

  * apt-key add fails in overlayfs (LP: #1618572)
    - SAUCE: overlayfs: fix regression in whiteout detection

linux (4.4.0-37.56) xenial; urgency=low

  [ Tim Gardner ]

  * Release Tracking Bug
    - LP: #1618040

  * [Feature] Instruction decoder support for new SKX instructions- AVX512
    (LP: #1591655)
    - x86/insn: perf tools: Fix vcvtph2ps instruction decoding
    - x86/insn: Add AVX-512 support to the instruction decoder
    - perf tools: Add AVX-512 support to the instruction decoder used by Intel PT
    - perf tools: Add AVX-512 instructions to the new instructions test

  * [Ubuntu 16.04] FCoE Lun not visible in OS with inbox driver - Issue with
    ioremap() call on 32bit kernel (LP: #1608652)
    - lpfc: Correct issue with ioremap() call on 32bit kernel

  * [Feature] turbostat support for Skylake-SP server (LP: #1591802)
    - tools/power turbostat: decode more CPUID fields
    - tools/power turbostat: CPUID(0x16) leaf shows base, max, and bus frequency
    - tools/power turbostat: decode HWP registers
    - tools/power turbostat: Decode MSR_MISC_PWR_MGMT
    - tools/power turbostat: allow sub-sec intervals
    - tools/power turbostat: Intel Xeon x200: fix erroneous bclk value
    - tools/power turbostat: Intel Xeon x200: fix turbo-ratio decoding
    - tools/power turbostat: re-name "%Busy" field to "Busy%"
    - tools/power turbostat: add --out option for saving output in a file
    - tools/power turbostat: fix compiler warnings
    - tools/power turbostat: make fewer systems calls
    - tools/power turbostat: show IRQs per CPU
    - tools/power turbostat: show GFXMHz
    - tools/power turbostat: show GFX%rc6
    - tools/power turbostat: detect and work around syscall jitter
    - tools/power turbostat: indicate SMX and SGX support
    - tools/power turbostat: call __cpuid() instead of __get_cpuid()
    - tools/power turbostat: correct output for MSR_NHM_SNB_PKG_CST_CFG_CTL dump
    - tools/power turbostat: bugfix: TDP MSRs print bits fixing
    - tools/power turbostat: SGX state should print only if --debug
    - tools/power turbostat: print IRTL MSRs
    - tools/power turbostat: initial BXT support
    - tools/power turbostat: decode BXT TSC frequency via CPUID
    - tools/power turbostat: initial SKX support

  * [BYT] display hotplug doesn't work on console (LP: #1616894)
    - drm/i915/vlv: Make intel_crt_reset() per-encoder
    - drm/i915/vlv: Reset the ADPA in vlv_display_power_well_init()
    - drm/i915/vlv: Disable HPD in valleyview_crt_detect_hotplug()
    - drm/i915: Enable polling when we don't have hpd

  * [Feature]intel_idle enabling on Broxton-P (LP: #1520446)
    - intel_idle: add BXT support

  * [Feature] EDAC: Update driver for SKX-SP (LP: #1591815)
    - [Config] CONFIG_EDAC_SKX=m
    - EDAC, skx_edac: Ad...