accessing /dev/hvc1 with stress-ng on Ubuntu xenial causes crash

Device is OK with 4.12, however, with 4.12 we get another issue:

[ 3996.652718] INFO: rcu_sched self-detected stall on CPU
[ 3996.652730] 23-...: (1 GPs behind) idle=73a/140000000000002/0 softirq=5179/5179 fqs=2475
[ 3996.652735] (t=5250 jiffies g=6889 c=6888 q=189)
[ 3996.652748] Task dump for CPU 23:
[ 3996.652749] kopald S 0 975 2 0x00000804
[ 3996.652752] Call Trace:
[ 3996.652759] [c000000fefafb0b0] [c000000000135a24] sched_show_task+0xd4/0x150 (unreliable)
[ 3996.652763] [c000000fefafb120] [c000000000c36b3c] rcu_dump_cpu_stacks+0xd0/0x134
[ 3996.652767] [c000000fefafb170] [c0000000001867a0] rcu_check_callbacks+0x8a0/0xb10
[ 3996.652769] [c000000fefafb2a0] [c000000000192958] update_process_times+0x48/0x90
[ 3996.652773] [c000000fefafb2d0] [c0000000001a9f60] tick_sched_handle.isra.8+0x30/0xb0
[ 3996.652775] [c000000fefafb300] [c0000000001aa044] tick_sched_timer+0x64/0xd0
[ 3996.652778] [c000000fefafb340] [c000000000193424] __hrtimer_run_queues+0x144/0x370
[ 3996.652780] [c000000fefafb3c0] [c00000000019449c] hrtimer_interrupt+0xfc/0x350
[ 3996.652784] [c000000fefafb490] [c000000000024658] __timer_interrupt+0x88/0x250
[ 3996.652787] [c000000fefafb4e0] [c000000000024a30] timer_interrupt+0x90/0xe0
[ 3996.652791] [c000000fefafb510] [c00000000000b6e0] restore_check_irq_replay+0x54/0x70
[ 3996.652795] --- interrupt: 901 at arch_local_irq_restore+0x74/0x90
                   LR = arch_local_irq_restore+0x74/0x90
[ 3996.652797] [c000000fefafb800] [c000000000194530] hrtimer_interrupt+0x190/0x350 (unreliable)
[ 3996.652801] [c000000fefafb820] [c000000000c3298c] __do_softirq+0xcc/0x41c
[ 3996.652804] [c000000fefafb900] [c0000000000fafa8] irq_exit+0xe8/0x120
[ 3996.652807] [c000000fefafb920] [c000000000024a34] timer_interrupt+0x94/0xe0
[ 3996.652810] [c000000fefafb950] [c00000000000b6e0] restore_check_irq_replay+0x54/0x70
[ 3996.652815] --- interrupt: 901 at lock_timer_base+0x70/0x100
                   LR = schedule_timeout+0x334/0x420
[ 3996.652817] [c000000fefafbc40] [0000000000000001] 0x1 (unreliable)
[ 3996.652821] [c000000fefafbca0] [c000000000c30a14] schedule_timeout+0x334/0x420
[ 3996.652824] [c000000fefafbd80] [c000000000095bf0] kopald+0x90/0xe0
[ 3996.652827] [c000000fefafbdc0] [c0000000001214cc] kthread+0x1ac/0x1c0
[ 3996.652831] [c000000fefafbe30] [c00000000000b2e8] ret_from_kernel_thread+0x5c/0x74
[ 4000.060643] NMI watchdog: BUG: soft lockup - CPU#23 stuck for 23s! [kopald:975]
[ 4000.060653] Modules linked in: kvm_hv kvm_pr kvm cuse userio hci_vhci bluetooth ecdh_generic uhid hid vhost_net vhost tap snd_seq snd_seq_device snd_timer snd soundcore powernv_op_panel uio_pdrv_genirq ipmi_powernv ipmi_devintf powernv_rng leds_powernv ibmpowernv vmx_crypto ipmi_msghandler uio ib_iser rdma_cm iw_cm ib_cm ib_core iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi autofs4 btrfs raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear dm_round_robin ses enclosure scsi_transport_sas crct10dif_vpmsum crc32c_vpmsum tg3 ipr scsi_dh_emc scsi_dh_rdac scsi_dh_alua dm_multipath
[ 4000.060735] CPU: 23 PID: 975 Comm: kopald Not tainted 4.12.0-11-generic #12
[ 4000...

OK in 4.10

Fix is upstream commit:

From bbc3dfe8805de86874b1a1b1429a002e8670043e Mon Sep 17 00:00:00 2001
From: Sam Mendoza-Jonas <email address hidden>
Date: Mon, 11 Jul 2016 13:38:57 +1000
Subject: [PATCH] tty/hvc: Use IRQF_SHARED for OPAL hvc consoles

Fix only required in Xenial, issue does not occur in Zesty upwards.

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 the problem still exists, change the tag 'verification-needed-xenial' to 'verification-failed-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!

The smoke test has passed on the ppc64le system "modoc" with Xenial kernel, thanks!

00:26:13 DEBUG| [stdout] Summary:
00:26:13 DEBUG| [stdout] Stressors run: 147
00:26:13 DEBUG| [stdout] Skipped: 2, bind-mount sock-diag
00:26:13 DEBUG| [stdout] Failed: 0,
00:26:13 DEBUG| [stdout] Oopsed: 0,
00:26:13 DEBUG| [stdout] Passed: 145, af-alg affinity aio aiol bigheap brk cache cap chdir chmod chown chroot clock clone context cpu crypt cyclic daemon dccp dentry dev dir dirdeep dnotify dup epoll eventfd fallocate fanotify fault fcntl fiemap fifo filename flock fork fp-error fstat full futex get getdent getrandom handle hdd icache icmp-flood inode-flags inotify io iomix ioprio itimer key kill klog lease link locka lockbus lockf lockofd madvise malloc membarrier memfd memrate memthrash mergesort mincore mknod mlock mmap mmapfork mmapmany mq mremap msg msync netdev netlink-proc nice null open personality pipe poll procfs pthread ptrace pty radixsort readahead rename rlimit rmap rtc schedpolicy sctp seal seccomp seek sem sem-sysv sendfile shm shm-sysv sigfd sigfpe sigpending sigq sigsegv sigsuspend sleep sock softlockup splice stackmmap stream switch symlink sync-file sysfs sysinfo tee timer timerfd tlb-shootdown tmpfs tsearch udp udp-flood unshare urandom userfaultfd utime vfork vm vm-rw vm-splice wait yield zero zombie

This bug was fixed in the package linux - 4.4.0-96.119

---------------
linux (4.4.0-96.119) xenial; urgency=low

  * linux: 4.4.0-96.119 -proposed tracker (LP: #1716613)

  * kernel panic -not syncing: Fatal exception: panic_on_oops (LP: #1708399)
    - s390/mm: no local TLB flush for clearing-by-ASCE IDTE
    - SAUCE: s390/mm: fix local TLB flushing vs. detach of an mm address space
    - SAUCE: s390/mm: fix race on mm->context.flush_mm

  * CVE-2017-1000251
    - Bluetooth: Properly check L2CAP config option output buffer length

linux (4.4.0-95.118) xenial; urgency=low

  * linux: 4.4.0-95.118 -proposed tracker (LP: #1715651)

  * Xenial update to 4.4.78 stable release broke Address Sanitizer
    (LP: #1715636)
    - mm: revert x86_64 and arm64 ELF_ET_DYN_BASE base changes

linux (4.4.0-94.117) xenial; urgency=low

  * linux: 4.4.0-94.117 -proposed tracker (LP: #1713462)

  * mwifiex causes kernel oops when AP mode is enabled (LP: #1712746)
    - SAUCE: net/wireless: do not dereference invalid pointer
    - SAUCE: mwifiex: do not dereference invalid pointer

  * Backport more recent Broadcom bnxt_en driver (LP: #1711056)
    - SAUCE: bnxt_en_bpo: Import bnxt_en driver version 1.8.1
    - SAUCE: bnxt_en_bpo: Drop distro out-of-tree detection logic
    - SAUCE: bnxt_en_bpo: Remove unnecessary compile flags
    - SAUCE: bnxt_en_bpo: Move config settings to Kconfig
    - SAUCE: bnxt_en_bpo: Remove PCI_IDs handled by the regular driver
    - SAUCE: bnxt_en_bpo: Rename the backport driver to bnxt_en_bpo
    - bnxt_en_bpo: [Config] Enable CONFIG_BNXT_BPO=m

  * HID: multitouch: Support ALPS PTP Stick and Touchpad devices (LP: #1712481)
    - HID: multitouch: Support PTP Stick and Touchpad device
    - SAUCE: HID: multitouch: Support ALPS PTP stick with pid 0x120A

  * igb: Support using Broadcom 54616 as PHY (LP: #1712024)
    - SAUCE: igb: add support for using Broadcom 54616 as PHY

  * IPR driver causes multipath to fail paths/stuck IO on Medium Errors
    (LP: #1682644)
    - scsi: ipr: do not set DID_PASSTHROUGH on CHECK CONDITION

  * accessing /dev/hvc1 with stress-ng on Ubuntu xenial causes crash
    (LP: #1711401)
    - tty/hvc: Use IRQF_SHARED for OPAL hvc consoles

  * memory-hotplug test needs to be fixed (LP: #1710868)
    - selftests: typo correction for memory-hotplug test
    - selftests: check hot-pluggagble memory for memory-hotplug test
    - selftests: check percentage range for memory-hotplug test
    - selftests: add missing test name in memory-hotplug test
    - selftests: fix memory-hotplug test

  * HP lt4132 LTE/HSPA+ 4G Module (03f0:a31d) does not work (LP: #1707643)
    - net: cdc_mbim: apply "NDP to end" quirk to HP lt4132

  * Migrating KSM page causes the VM lock up as the KSM page merging list is too
    large (LP: #1680513)
    - ksm: introduce ksm_max_page_sharing per page deduplication limit
    - ksm: fix use after free with merge_across_nodes = 0
    - ksm: cleanup stable_node chain collapse case
    - ksm: swap the two output parameters of chain/chain_prune
    - ksm: optimize refile of stable_node_dup at the head of the chain

  * sort ABI files with C.UTF-8 locale (LP: #1712345)
    - [Packaging] sort ABI ...