Commit 54473e0e authored Aug 04, 2025 by Thomas Gleixner

perf/core: Preserve AUX buffer allocation failure result



A recent overhaul sets the return value to 0 unconditionally after the
allocations, which causes reference count leaks and corrupts the user->vm
accounting.

Preserve the AUX buffer allocation failure return value, so that the
subsequent code works correctly.

Fixes: 0983593f ("perf/core: Lift event->mmap_mutex in perf_mmap()")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: stable@vger.kernel.org

parent 7e161a99

kernel/events/core.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -7115,6 +7115,7 @@ static int perf_mmap(struct file file, struct vm_area_struct vma)
		perf_event_update_time(event);
		perf_event_init_userpage(event);
		perf_event_update_userpage(event);
		ret = 0;
		} else {
		ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
		event->attr.aux_watermark, flags);
		@@ -7122,8 +7123,6 @@ static int perf_mmap(struct file file, struct vm_area_struct vma)
		rb->aux_mmap_locked = extra;
		}

		ret = 0;

		unlock:
		if (!ret) {
		atomic_long_add(user_extra, &user->locked_vm);