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);