5.4-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Gleixner tglx@linutronix.de
commit 5468c0fbccbb9d156522c50832244a8b722374fb upstream.
Failure of the AUX buffer allocation leaks the reference count.
Set the reference count to 1 only when the allocation succeeds.
Fixes: 45bfb2e50471 ("perf/core: 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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/events/core.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
--- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5877,9 +5877,7 @@ static int perf_mmap(struct file *file, goto unlock; }
- atomic_set(&rb->aux_mmap_count, 1); user_extra = nr_pages; - goto accounting; }
@@ -5986,8 +5984,10 @@ accounting: } 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: @@ -5997,6 +5997,7 @@ unlock:
atomic_inc(&event->mmap_count); } else if (rb) { + /* AUX allocation failed */ atomic_dec(&rb->mmap_count); } aux_unlock: