Firefox hangs then 17.04 won't shutdown and misbehaves

After upgrading online to 17.04 all looked good. Expected normal operation of OS. But after using Firefox for a few hours, it greys out 'not responding', CPU rises to 100%, and Operating system commands malfunction.

firefox:
  Installed: 53.0+build6-0ubuntu0.17.04.1
  Candidate: 53.0+build6-0ubuntu0.17.04.1
  Version table:
 *** 53.0+build6-0ubuntu0.17.04.1 500
        500 http://gb.archive.ubuntu.com/ubuntu zesty-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu zesty-security/main amd64 Packages
        100 /var/lib/dpkg/status
     50.1.0+build2-0ubuntu1 500
        500 http://gb.archive.ubuntu.com/ubuntu zesty/main amd64 Packages

Closing Firefox leaves Firefox running 100% in background. Open terminal ctrl-alt-T and get shell, ps command works, but ps -ef | grep firefox hangs terminal. Firefox pid ignores kill -9. shutdown from screen button hangs system. Terminal 'shutdown -t now' also hangs system.

syslog contains kernel bug message:

May 9 11:08:00 hawk kernel: [ 6143.424077] ------------[ cut here ]------------
May 9 11:08:00 hawk kernel: [ 6143.424127] kernel BUG at /build/linux-2NWldV/linux-4.10.0/include/linux/swapops.h:129!
May 9 11:08:00 hawk kernel: [ 6143.424187] invalid opcode: 0000 [#1] SMP
May 9 11:08:00 hawk kernel: [ 6143.424218] Modules linked in: rfcomm cmac bnep binfmt_misc snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp snd_hda_intel kvm_intel snd_hda_codec kvm btusb btrtl irqbypass btbcm crct10dif_pclmul btintel snd_hda_core crc32_pclmul bluetooth ghash_clmulni_intel joydev pcbc snd_hwdep input_leds snd_pcm aesni_intel aes_x86_64 snd_seq_midi crypto_simd snd_seq_midi_event glue_helper snd_rawmidi cryptd snd_seq intel_cstate intel_rapl_perf snd_seq_device snd_timer serio_raw snd soundcore mei_me shpchp lpc_ich mei ie31200_edac edac_core tpm_infineon mac_hid parport_pc ppdev lp parport ip_tables x_tables autofs4 hid_generic usbhid hid i915 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops psmouse ahci drm r8169
May 9 11:08:00 hawk kernel: [ 6143.424746] libahci mii fjes video
May 9 11:08:00 hawk kernel: [ 6143.424779] CPU: 4 PID: 3124 Comm: JS Helper Not tainted 4.10.0-20-generic #22-Ubuntu
May 9 11:08:00 hawk kernel: [ 6143.424836] Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./B75M-D3H, BIOS F15 10/23/2013
May 9 11:08:00 hawk kernel: [ 6143.424907] task: ffff8baa99dd4380 task.stack: ffffa42342864000
May 9 11:08:00 hawk kernel: [ 6143.424956] RIP: 0010:__migration_entry_wait+0x16a/0x180
May 9 11:08:00 hawk kernel: [ 6143.424997] RSP: 0000:ffffa42342867d68 EFLAGS: 00010246
May 9 11:08:00 hawk kernel: [ 6143.425037] RAX: 0017ffffc0048078 RBX: ffffe147462e17b0 RCX: ffffe147462e17b0
May 9 11:08:00 hawk kernel: [ 6143.425089] RDX: 0000000000000001 RSI: ffff8baa4b85e800 RDI: ffffe14744884000
May 9 11:08:00 hawk kernel: [ 6143.425141] RBP: ffffa42342867d80 R08: ffff8baacbfaf440 R09: ffff8baacbfaf440
May 9 11:08:00 hawk kernel: [ 6143.425193] R10: 00007f52397000c8 R11: 0000000000000206 R12: ffffe14744884000
May 9 11:08:00 hawk kernel: [ 6143.425246] R13: 3e00000000122100 R14: ffffa42342867e30 R15: ffff8baa4ba9ac80
May 9 11:08:00 hawk kernel: [ 6143.425299] FS: 00007f521c9f9700(0000) GS:ffff8baade300000(0000) knlGS:0000000000000000
May 9 11:08:00 hawk kernel: [ 6143.425358] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
May 9 11:08:00 hawk kernel: [ 6143.425400] CR2: 00007f51f1d00018 CR3: 00000001a895f000 CR4: 00000000001406e0
May 9 11:08:00 hawk kernel: [ 6143.425453] Call Trace:
May 9 11:08:00 hawk kernel: [ 6143.425477] migration_entry_wait+0x74/0x80
May 9 11:08:00 hawk kernel: [ 6143.425512] do_swap_page+0x5b3/0x770
May 9 11:08:00 hawk kernel: [ 6143.425542] handle_mm_fault+0x873/0x1360
May 9 11:08:00 hawk kernel: [ 6143.425577] __do_page_fault+0x23e/0x4e0
May 9 11:08:00 hawk kernel: [ 6143.425609] do_page_fault+0x22/0x30
May 9 11:08:00 hawk kernel: [ 6143.425640] page_fault+0x28/0x30
May 9 11:08:00 hawk kernel: [ 6143.425667] RIP: 0033:0x562c5f3822b4
May 9 11:08:00 hawk kernel: [ 6143.425695] RSP: 002b:00007f521c9f8c40 EFLAGS: 00010203
May 9 11:08:00 hawk kernel: [ 6143.425756] RAX: 0000000000000000 RBX: 00007f5239700040 RCX: 00007f5239905137
May 9 11:08:00 hawk kernel: [ 6143.425835] RDX: 0000000000000008 RSI: 0000000000002000 RDI: 00007f51f1df8000
May 9 11:08:00 hawk kernel: [ 6143.425914] RBP: 00007f51f1d00000 R08: 00007f52397000c8 R09: 0000000000000000
May 9 11:08:00 hawk kernel: [ 6143.425993] R10: 00007f52397000c8 R11: 0000000000000206 R12: 0000000000000080
May 9 11:08:00 hawk kernel: [ 6143.426073] R13: 00007f52397000c8 R14: 00000000000000f7 R15: 0000000000000002
May 9 11:08:00 hawk kernel: [ 6143.426152] Code: ff ff ff 4c 89 e7 e8 96 a2 f8 ff e9 3c ff ff ff 85 d2 0f 84 2a ff ff ff 8d 4a 01 89 d0 f0 41 0f b1 4d 00 39 d0 74 81 89 c2 eb e5 <0f> 0b 4c 89 e7 e8 0c fb f9 ff eb b8 4c 8d 60 ff 4c 8d 68 1b eb
May 9 11:08:00 hawk kernel: [ 6143.426330] RIP: __migration_entry_wait+0x16a/0x180 RSP: ffffa42342867d68
May 9 11:08:00 hawk kernel: [ 6143.444454] ---[ end trace 738202c4a5ad47e4 ]---
May 9 11:08:25 hawk kernel: [ 6167.963166] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [JS Helper:3129]

more similar...

Thanks.

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: ubuntu-release-upgrader-core 1:17.04.7
ProcVersionSignature: Ubuntu 4.10.0-20.22-generic 4.10.8
Uname: Linux 4.10.0-20-generic x86_64
ApportVersion: 2.20.4-0ubuntu4
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: Unity:Unity7
Date: Tue May 9 11:54:19 2017
InstallationDate: Installed on 2014-04-10 (1125 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en_GB:en
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
Symptom: dist-upgrade
UpgradeStatus: Upgraded to zesty on 2017-04-25 (13 days ago)
VarLogDistupgradeTermlog: