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-rw-r--r--kernel/events/core.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 45edb85344a1..fb662eb4fb69 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5895,11 +5895,11 @@ static void perf_pmu_output_stop(struct perf_event *event);
static void perf_mmap_close(struct vm_area_struct *vma)
{
struct perf_event *event = vma->vm_file->private_data;
-
struct perf_buffer *rb = ring_buffer_get(event);
struct user_struct *mmap_user = rb->mmap_user;
int mmap_locked = rb->mmap_locked;
unsigned long size = perf_data_size(rb);
+ bool detach_rest = false;
if (event->pmu->event_unmapped)
event->pmu->event_unmapped(event, vma->vm_mm);
@@ -5930,7 +5930,8 @@ static void perf_mmap_close(struct vm_area_struct *vma)
mutex_unlock(&event->mmap_mutex);
}
- atomic_dec(&rb->mmap_count);
+ if (atomic_dec_and_test(&rb->mmap_count))
+ detach_rest = true;
if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
goto out_put;
@@ -5939,7 +5940,7 @@ static void perf_mmap_close(struct vm_area_struct *vma)
mutex_unlock(&event->mmap_mutex);
/* If there's still other mmap()s of this buffer, we're done. */
- if (atomic_read(&rb->mmap_count))
+ if (!detach_rest)
goto out_put;
/*