[PATCH 4.9 45/72] parisc: Avoid stalled CPU warnings after system shutdown

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Helge Deller <deller@xxxxxx>

commit 476e75a44b56038bee9207242d4bc718f6b4de06 upstream.

Commit 73580dac7618 ("parisc: Fix system shutdown halt") introduced an endless
loop for systems which don't provide a software power off function.  But the
soft lockup detector will detect this and report stalled CPUs after some time.
Avoid those unwanted warnings by disabling the soft lockup detector.

Fixes: 73580dac7618 ("parisc: Fix system shutdown halt")
Signed-off-by: Helge Deller <deller@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/parisc/kernel/process.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -140,6 +140,8 @@ void machine_power_off(void)
 	printk(KERN_EMERG "System shut down completed.\n"
 	       "Please power this system off now.");
 
+	/* prevent soft lockup/stalled CPU messages for endless loop. */
+	rcu_sysrq_start();
 	for (;;);
 }