[PATCH] prevent sparc64 from invoking irq handlers on offline CPUs

[Paul E. McKenney]

Make sparc64 refrain from clearing a given to-be-offlined CPU's bit in the
cpu_online_mask until it has processed pending irqs.  This change
prevents other CPUs from being blindsided by an apparently offline CPU
nevertheless changing globally visible state.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---

 smp.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c
index 743ccad..b83a683 100644
--- a/arch/sparc64/kernel/smp.c
+++ b/arch/sparc64/kernel/smp.c
@@ -1305,10 +1305,6 @@ int __cpu_disable(void)
 	c->core_id = 0;
 	c->proc_id = -1;
 
-	spin_lock(&call_lock);
-	cpu_clear(cpu, cpu_online_map);
-	spin_unlock(&call_lock);
-
 	smp_wmb();
 
 	/* Make sure no interrupts point to this cpu.  */
@@ -1318,6 +1314,10 @@ int __cpu_disable(void)
 	mdelay(1);
 	local_irq_disable();
 
+	spin_lock(&call_lock);
+	cpu_clear(cpu, cpu_online_map);
+	spin_unlock(&call_lock);
+
 	return 0;
 }
 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/