static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head, call_single_queue);
+static DEFINE_PER_CPU(atomic_t, trigger_backtrace) = ATOMIC_INIT(1);
+
static void __flush_smp_call_function_queue(bool warn_cpu_offline);
int smpcfd_prepare_cpu(unsigned int cpu)
*bug_id, !cpu_cur_csd ? "unresponsive" : "handling this request");
}
if (cpu >= 0) {
- dump_cpu_task(cpu);
+ if (atomic_cmpxchg_acquire(&per_cpu(trigger_backtrace, cpu), 1, 0))
+ dump_cpu_task(cpu);
if (!cpu_cur_csd) {
pr_alert("csd: Re-sending CSD lock (#%d) IPI from CPU#%02d to CPU#%02d\n", *bug_id, raw_smp_processor_id(), cpu);
arch_send_call_function_single_ipi(cpu);
struct llist_node *entry, *prev;
struct llist_head *head;
static bool warned;
+ atomic_t *tbt;
lockdep_assert_irqs_disabled();
+ /* Allow waiters to send backtrace NMI from here onwards */
+ tbt = this_cpu_ptr(&trigger_backtrace);
+ atomic_set_release(tbt, 1);
+
head = this_cpu_ptr(&call_single_queue);
entry = llist_del_all(head);
entry = llist_reverse_order(entry);