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Commit 7d4d6154 authored by Nathan Lynch's avatar Nathan Lynch Committed by Paul Mackerras
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[PATCH] powerpc: avoid timer interrupt replay effect when onlining cpu 



When a cpu is hotplug-onlined, if we don't set per_cpu(last_jiffy) to
something sane, timer_interrupt will execute its while loop for every
tick missed since the cpu was last online (or since the system was
booted, if we're adding a new cpu).  This can cause weird hangs, ssh
sessions dropping, and we can even go xmon if we take a global IPI at
the wrong time.

Signed-off-by: default avatarNathan Lynch <ntl@pobox.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 4dc43256

arch/powerpc/kernel/smp.c

+3 −0
Original line number Diff line number Diff line
@@ -540,6 +540,9 @@ int __devinit start_secondary(void *unused) 
	if (smp_ops->take_timebase)

		smp_ops->take_timebase();



	if (system_state > SYSTEM_BOOTING)

		per_cpu(last_jiffy, cpu) = get_tb();



	spin_lock(&call_lock);

	cpu_set(cpu, cpu_online_map);

	spin_unlock(&call_lock);