Merge tag 'v3.16-rc1' into x86/cpufeature

Linux 3.16-rc1

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 15 insertions, 3 deletions

diff --git a/kernel/smp.c b/kernel/smp.c
index 06d574e42c72..306f8180b0d5 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -185,14 +185,26 @@ void generic_smp_call_function_single_interrupt(void)
 {
 	struct llist_node *entry;
 	struct call_single_data *csd, *csd_next;
+	static bool warned;
+
+	entry = llist_del_all(&__get_cpu_var(call_single_queue));
+	entry = llist_reverse_order(entry);
 
 	/*
 	 * Shouldn't receive this interrupt on a cpu that is not yet online.
 	 */
-	WARN_ON_ONCE(!cpu_online(smp_processor_id()));
+	if (unlikely(!cpu_online(smp_processor_id()) && !warned)) {
+		warned = true;
+		WARN(1, "IPI on offline CPU %d\n", smp_processor_id());
 
-	entry = llist_del_all(&__get_cpu_var(call_single_queue));
-	entry = llist_reverse_order(entry);
+		/*
+		 * We don't have to use the _safe() variant here
+		 * because we are not invoking the IPI handlers yet.
+		 */
+		llist_for_each_entry(csd, entry, llist)
+			pr_warn("IPI callback %pS sent to offline CPU\n",
+				csd->func);
+	}
 
 	llist_for_each_entry_safe(csd, csd_next, entry, llist) {
 		csd->func(csd->info);