perf/core: Don't leak AUX buffer refcount on allocation failure

Failure of the AUX buffer allocation leaks the reference count.

Set the reference count to 1 only when the allocation succeeds.

Fixes: 45bfb2e50471 ("perf: Add AUX area to ring buffer for raw data streams")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: stable@vger.kernel.org

diff --git a/kernel/events/core.c b/kernel/events/core.c
index c05262e15b7d7f6c99ff1ed23565f205030ed6b3..e89e772285912e51859a8d6a196bde8662e8d989 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7051,8 +7051,6 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
                        ret = 0;
                        goto unlock;
                }
-
-               atomic_set(&rb->aux_mmap_count, 1);
        }
 
        user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
@@ -7119,8 +7117,10 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
        } else {
                ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
                                   event->attr.aux_watermark, flags);
-               if (!ret)
+               if (!ret) {
+                       atomic_set(&rb->aux_mmap_count, 1);
                        rb->aux_mmap_locked = extra;
+               }
        }
 
 unlock:
@@ -7130,6 +7130,7 @@ unlock:
 
                atomic_inc(&event->mmap_count);
        } else if (rb) {
+               /* AUX allocation failed */
                atomic_dec(&rb->mmap_count);
        }
 aux_unlock: