Backport cxlflash patch related to EEH recovery into Xenial SRU stream

[bugproxy]

---Problem Description---
Request to backport cxlflash EEH patch to Xenial SRU

---System Hang---
 When a cxlflash adapter goes into EEH recovery and multiple processes
(each having established its own context) are active, the EEH recovery
can hang if the processes attempt to recover in parallel.
After debugging the problem, patch has been upstreamed for this issue and the system has been rebooted with the fix for the problem

---Steps to Reproduce---
 Injecting EEH when multiple processes are active can trigger the issue

Stack trace output:
     Call Trace:
    __switch_to+0x2f0/0x410
    __schedule+0x300/0x980
    schedule+0x48/0xc0
    rwsem_down_write_failed+0x294/0x410
    down_write+0x88/0xb0
    cxlflash_pci_error_detected+0x100/0x1c0 [cxlflash]
    cxl_vphb_error_detected+0x88/0x110 [cxl]
    cxl_pci_error_detected+0xb0/0x1d0 [cxl]
    eeh_report_error+0xbc/0x130
    eeh_pe_dev_traverse+0x94/0x160
    eeh_handle_normal_event+0x17c/0x450
    eeh_handle_event+0x184/0x370
    eeh_event_handler+0x1c8/0x1d0
    kthread+0x110/0x130
    ret_from_kernel_thread+0x5c/0xa4
    INFO: task blockio:33215 blocked for more than 120 seconds.

The upstream patch we need backported to Xenial SRU stream is

635f6b0893cff193a1774881ebb1e4a4b9a7fead
    cxlflash: Fix to resolve dead-lock during EEH recovery

[Kamal Mostafa (kamalmostafa)]

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!

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 4.4.0-28.47

---------------
linux (4.4.0-28.47) xenial; urgency=low

  [ Luis Henriques ]

  * Release Tracking Bug
    - LP: #1595874

  * Linux netfilter local privilege escalation issues (LP: #1595350)
    - netfilter: x_tables: don't move to non-existent next rule
    - netfilter: x_tables: validate targets of jumps
    - netfilter: x_tables: add and use xt_check_entry_offsets
    - netfilter: x_tables: kill check_entry helper
    - netfilter: x_tables: assert minimum target size
    - netfilter: x_tables: add compat version of xt_check_entry_offsets
    - netfilter: x_tables: check standard target size too
    - netfilter: x_tables: check for bogus target offset
    - netfilter: x_tables: validate all offsets and sizes in a rule
    - netfilter: x_tables: don't reject valid target size on some architectures
    - netfilter: arp_tables: simplify translate_compat_table args
    - netfilter: ip_tables: simplify translate_compat_table args
    - netfilter: ip6_tables: simplify translate_compat_table args
    - netfilter: x_tables: xt_compat_match_from_user doesn't need a retval
    - netfilter: x_tables: do compat validation via translate_table
    - netfilter: x_tables: introduce and use xt_copy_counters_from_user

  * Linux netfilter IPT_SO_SET_REPLACE memory corruption (LP: #1555338)
    - netfilter: x_tables: validate e->target_offset early
    - netfilter: x_tables: make sure e->next_offset covers remaining blob size
    - netfilter: x_tables: fix unconditional helper

linux (4.4.0-27.46) xenial; urgency=low

  [ Kamal Mostafa ]

  * Release Tracking Bug
    - LP: #1594906

  * Support Edge Gateway's Bluetooth LED (LP: #1512999)
    - Revert "UBUNTU: SAUCE: Bluetooth: Support for LED on Marvell modules"

linux (4.4.0-26.45) xenial; urgency=low

  [ Kamal Mostafa ]

  * Release Tracking Bug
    - LP: #1594442

  * linux: Implement secure boot state variables (LP: #1593075)
    - SAUCE: UEFI: Add secure boot and MOK SB State disabled sysctl

  * failures building userspace packages that include ethtool.h (LP: #1592930)
    - ethtool.h: define INT_MAX for userland

linux (4.4.0-25.44) xenial; urgency=low

  [ Kamal Mostafa ]

  * Release Tracking Bug
    - LP: #1591289

  * Xenial update to v4.4.13 stable release (LP: #1590455)
    - MIPS64: R6: R2 emulation bugfix
    - MIPS: math-emu: Fix jalr emulation when rd == $0
    - MIPS: MSA: Fix a link error on `_init_msa_upper' with older GCC
    - MIPS: Don't unwind to user mode with EVA
    - MIPS: Avoid using unwind_stack() with usermode
    - MIPS: Fix siginfo.h to use strict posix types
    - MIPS: Fix uapi include in exported asm/siginfo.h
    - MIPS: Fix watchpoint restoration
    - MIPS: Flush highmem pages in __flush_dcache_page
    - MIPS: Handle highmem pages in __update_cache
    - MIPS: Sync icache & dcache in set_pte_at
    - MIPS: ath79: make bootconsole wait for both THRE and TEMT
    - MIPS: Reserve nosave data for hibernation
    - MIPS: Loongson-3: Reserve 32MB for RS780E integrated GPU
    - MIPS: Use copy_s.fmt rather than copy_u.fmt
    - MIPS: Fix MSA ld_*/st_* asm macros to use PTR_ADDU
    - MIPS: Prevent "restoration" of MSA c...