diff options
| -rw-r--r-- | lib/percpu-refcount.c | 12 |
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); |