Merge tag 'irqchip-fixes-5.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/urgent

Pull irqchip fixes from Marc Zyngier:

  - More compatible strings for the Ingenic irqchip (introducing the
    JZ4760B SoC)
  - Select GENERIC_IRQ_MULTI_HANDLER on the ARM ep93xx platform
  - Drop all GENERIC_IRQ_MULTI_HANDLER selections from the irqchip
    Kconfig, now relying on the architecture to get it right
  - Drop the debugfs_file field from struct irq_domain, now that
    debugfs can track things on its own

1 files changed, 9 insertions, 3 deletions

diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c
index e59eda07305e..a1071cdefb5a 100644
--- a/lib/percpu-refcount.c
+++ b/lib/percpu-refcount.c
@@ -5,6 +5,7 @@
 #include <linux/sched.h>
 #include <linux/wait.h>
 #include <linux/slab.h>
+#include <linux/mm.h>
 #include <linux/percpu-refcount.h>
 
 /*
@@ -168,6 +169,7 @@ static void percpu_ref_switch_to_atomic_rcu(struct rcu_head *rcu)
 			struct percpu_ref_data, rcu);
 	struct percpu_ref *ref = data->ref;
 	unsigned long __percpu *percpu_count = percpu_count_ptr(ref);
+	static atomic_t underflows;
 	unsigned long count = 0;
 	int cpu;
 
@@ -191,9 +193,13 @@ static void percpu_ref_switch_to_atomic_rcu(struct rcu_head *rcu)
 	 */
 	atomic_long_add((long)count - PERCPU_COUNT_BIAS, &data->count);
 
-	WARN_ONCE(atomic_long_read(&data->count) <= 0,
-		  "percpu ref (%ps) <= 0 (%ld) after switching to atomic",
-		  data->release, atomic_long_read(&data->count));
+	if (WARN_ONCE(atomic_long_read(&data->count) <= 0,
+		      "percpu ref (%ps) <= 0 (%ld) after switching to atomic",
+		      data->release, atomic_long_read(&data->count)) &&
+	    atomic_inc_return(&underflows) < 4) {
+		pr_err("%s(): percpu_ref underflow", __func__);
+		mem_dump_obj(data);
+	}
 
 	/* @ref is viewed as dead on all CPUs, send out switch confirmation */
 	percpu_ref_call_confirm_rcu(rcu);