kselftest:lost_exception_test failure with 4.11.0-rc5

[Sachin Sant]

I have run into few instances where the lost_exception_test from
powerpc kselftest fails with SIGABRT. Following o/p is against
4.11.0-rc5. The failure is intermittent. 

When the test fails it is killed due to SIGABRT.

# ./lost_exception_test 
test: lost_exception
tags: git_version:unknown
Binding to cpu 8
main test running as pid 9208
EBB Handler is at 0x10003dcc
!! killing lost_exception
ebb_state:
  ebb_count    = 191529
  spurious     = 0
  negative     = 0
  no_overflow  = 0
  pmc[1] count = 0x0
  pmc[2] count = 0x0
  pmc[3] count = 0x0
  pmc[4] count = 0x4c1b707
  pmc[5] count = 0x0
  pmc[6] count = 0x0
HW state:
MMCR0 0x0000000080000080 FC PMAO 
MMCR2 0x0000000000000000
EBBHR 0x0000000010003dcc
BESCR 0x8000000100000000 GE PMAE 
PMC1  0x0000000000000000
PMC2  0x0000000000000000
PMC3  0x0000000000000000
PMC4  0x0000000080000000
PMC5  0x0000000088d4f0c8
PMC6  0x000000001e49da22
SIAR  0x00003fffad60a608
!! child died by signal 6
failure: lost_exception
#

Thanks
-Sachin