[PATCH] x86_64: Fix cluster mode send_IPI_allbutself to use get_cpu()/put_cpu()

Need to ensure we dont get prempted when we clear ourself from mask when using
clustered mode genapic code.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Acked-by: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 5 insertions, 1 deletions

diff --git a/arch/x86_64/kernel/genapic_cluster.c b/arch/x86_64/kernel/genapic_cluster.c
index 9703da7202e3..f6523dd1bc09 100644
--- a/arch/x86_64/kernel/genapic_cluster.c
+++ b/arch/x86_64/kernel/genapic_cluster.c
@@ -72,10 +72,14 @@ static void cluster_send_IPI_mask(cpumask_t mask, int vector)
 static void cluster_send_IPI_allbutself(int vector)
 {
         cpumask_t mask = cpu_online_map;
-        cpu_clear(smp_processor_id(), mask);
+        int me = get_cpu(); /* Ensure we are not preempted when we clear */
+
+        cpu_clear(me, mask);
 
         if (!cpus_empty(mask))
                 cluster_send_IPI_mask(mask, vector);
+
+        put_cpu();
 }
 
 static void cluster_send_IPI_all(int vector)