Public bug reported:

Problem description
Fix for flushing TM on coredump only if CPU has TM feature
---Additional Hardware Info---
POWER9/POWER8/compat mode 
Machine Type = P9 baremetal + VM (POWER9, POWER8, Compat mode) 
---Steps to Reproduce---
 On POWER9 machines it's possible that TM is disabled for use by the VMs and if 
a coredump is generated in the VM it will crash since it will execute TM 
instructions when coredumping if a check is not present on the VM's kernel. 
Since POWER9 can run VM on P8 compatibility mode, it's necessary to patch all 
kernels that run on compat mode as well.
Stack trace output:
Oops output:
 PID: 16438  TASK: c000000272f515e0  CPU: 3   COMMAND: "vma05_vdso"
 #0 [c0000002711f7050] crash_kexec at c0000000001a07e4
 #1 [c0000002711f7080] die at c000000000025278
 #2 [c0000002711f7120] _exception at c000000000025594
 #3 [c0000002711f72b0] program_check_exception at c000000000a0e1b8
 #4 [c0000002711f7330] program_check_common at c000000000006308
 Program Check [700] exception frame:
 R0:  0000000000000000    R1:  c0000002711f7620    R2:  c000000001274700
 R3:  c000000272f51af0    R4:  800000010280b033    R5:  0000000000000000
 R6:  0000000000000100    R7:  0000000000000000    R8:  0000000000000000
 R9:  0000000200000000    R10: 0000000000000000    R11: 0000000000000000
 R12: c000000000010720    R13: c000000007b81b00    R14: 0000000000000000
 R15: 0000000000000000    R16: c0000002711f7db0    R17: 0000000000040006
 R18: c00000002ab95800    R19: 0000000000000100    R20: 0000000000000001
 R21: 0000000000000002    R22: c000000000bfc1c8    R23: c0000002711f79b8
 R24: c000000000a30480    R25: c000000000a30478    R26: 0000000000000018
 R27: 0000000000000000    R28: c00000002ab95800    R29: 0000000000000000
 R30: 0000000000000100    R31: c000000272f515e0
 NIP: c00000000005b10c    MSR: 800000010288b033    OR3: c0000000000108e0
 CTR: c000000000010720    LR:  c0000000000108e4    XER: 0000000020000000
 CCR: 0000000028002448    MQ:  0000000000000001    DAR: c000000275599748
 DSISR: c000000274092988     Syscall Result: 0000000000000000
 #5 [c0000002711f7620] tm_save_sprs at c00000000005b10c
 [Link Register] [c0000002711f7620] vsr_get at c0000000000108e4
 #6 [c0000002711f7770] fill_thread_core_info at c0000000003d8b44
 #7 [c0000002711f7820] fill_note_info at c0000000003d8e94
 #8 [c0000002711f78b0] elf_core_dump at c0000000003d94d4
 #9 [c0000002711f7a90] do_coredump at c0000000003dfcf4
#10 [c0000002711f7c20] get_signal_to_deliver at c0000000001061d4
#11 [c0000002711f7d10] do_signal at c00000000001beac
#12 [c0000002711f7e00] do_notify_resume at c00000000001c2cc
#13 [c0000002711f7e30] ret_from_except_lite at c00000000000a7b0
 System Call [c00] exception frame:
 R0:  00000000000000fa    R1:  00003fffd0470f00    R2:  00003fffa8af7f00
 R3:  0000000000000000    R4:  0000000000004036    R5:  000000000000000b
 R6:  00003fffd0471428    R7:  0000000010000770    R8:  0000000000004036
 R9:  0000000000000000    R10: 0000000000000000    R11: 0000000000000000
 R12: 0000000000000000    R13: 00003fffa8babb80    R14: 0000000000000000
 R15: 0000000000000000    R16: 0000000000000000    R17: 0000000000000000
 R18: 0000000000000000    R19: 0000000000000000    R20: 0000000000000000
 R21: 0000000000000000    R22: 0000000000000000    R23: 0000000000000000
 R24: 0000000000000000    R25: 0000000000000000    R26: 0000000000000000
 R27: 00003fffa8b9fbb8    R28: 00003fffa8ba0000    R29: 00003fffa8b9f550
 R30: 0000000000000000    R31: 0000000000000000
 NIP: 00003fffa8ad54c8    MSR: 800000000000d033    OR3: 0000000000004036
 CTR: 0000000000000000    LR:  000000001000055c    XER: 0000000000000000
 CCR: 0000000042000442    MQ:  0000000000000001    DAR: 00003fffa89b2100
 DSISR: 0000000040000000     Syscall Result: 0000000000000000

== Comment: #1 - Gustavo Bueno Romero <> - 2018-04-12 
17:24:21 ==
Dear maintainer, please cherry-pick the fix alreayd available upstream 
containing the additional check to avoid the issue here described. It must 
apply cleanly on stable kernels:

"powerpc/tm: Flush TM only if CPU has TM feature":

Please cherry-pick the pointed out fix and apply it to kernel:

HWE 4.x
HWE 4.13

HWE-edge 4.15 already has the fix in place.

** Affects: ubuntu-power-systems
     Importance: High
     Assignee: Canonical Kernel Team (canonical-kernel-team)
         Status: Triaged

** Affects: linux (Ubuntu)
     Importance: Undecided
     Assignee: Ubuntu on IBM Power Systems Bug Triage (ubuntu-power-triage)
         Status: New

** Tags: architecture-ppc64le bugnameltc-166685 severity-high 
targetmilestone-inin16044 triage-g

** Tags added: architecture-ppc64le bugnameltc-166685 severity-high

** Changed in: ubuntu
     Assignee: (unassigned) => Ubuntu on IBM Power Systems Bug Triage 

** Package changed: ubuntu => linux (Ubuntu)

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  Fix for flushing TM on coredump only if CPU has TM feature

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