[PATCH v4 0/5] powerpc: watchdog fixes

[Nicholas Piggin <npiggin@gmail.com>]

These are some watchdog fixes and improvements, in particular a
deadlock between the wd_smp_lock and console lock when the watchdog
fires, found by Laurent.

Thanks,
Nick

Since v3:
- Rebased on upstream.
- Brought patch 5 into the series.
- Fix bug with SMP watchdog last heartbeat time reporting.

Since v2:
- Fix a false positive warning in patch 1 found by Laurent.
- Move a comment change hunk to the correct patch.
- Drop the patch that removed the unstuck backtrace which is considered
  useful.

Since v1:
- Fixes noticed by Laurent in v1.
- Correct the description of the ABBA deadlock I wrote incorrectly in
  v1.
- Made several other improvements (patches 2,4,5).

Nicholas Piggin (5):
  powerpc/watchdog: Fix missed watchdog reset due to memory ordering
    race
  powerpc/watchdog: tighten non-atomic read-modify-write access
  powerpc/watchdog: Avoid holding wd_smp_lock over printk and
    smp_send_nmi_ipi
  powerpc/watchdog: read TB close to where it is used
  powerpc/watchdog: help remote CPUs to flush NMI printk output

 arch/powerpc/kernel/watchdog.c | 223 ++++++++++++++++++++++++++-------
 1 file changed, 180 insertions(+), 43 deletions(-)

-- 
2.23.0