static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
{
	struct perf_event_context *child_ctx, *clone_ctx = NULL;
	struct perf_event *child_event, *next;

	WARN_ON_ONCE(child != current);

	child_ctx = perf_pin_task_context(child, ctxn);
	if (!child_ctx)
		return;

	/*
	 * In order to reduce the amount of tricky in ctx tear-down, we hold
	 * ctx::mutex over the entire thing. This serializes against almost
	 * everything that wants to access the ctx.
	 *
	 * The exception is sys_perf_event_open() /
	 * perf_event_create_kernel_count() which does find_get_context()
	 * without ctx::mutex (it cannot because of the move_group double mutex
	 * lock thing). See the comments in perf_install_in_context().
	 */
	mutex_lock(&child_ctx->mutex);

	/*
	 * In a single ctx::lock section, de-schedule the events and detach the
	 * context from the task such that we cannot ever get it scheduled back
	 * in.
	 */
	raw_spin_lock_irq(&child_ctx->lock);
	task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);

	/*
	 * Now that the context is inactive, destroy the task <-> ctx relation
	 * and mark the context dead.
	 */
	RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
	put_ctx(child_ctx); /* cannot be last */
	WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
	put_task_struct(current); /* cannot be last */

	clone_ctx = unclone_ctx(child_ctx);
	raw_spin_unlock_irq(&child_ctx->lock);

	if (clone_ctx)
		put_ctx(clone_ctx);

	/*
	 * Report the task dead after unscheduling the events so that we
	 * won't get any samples after PERF_RECORD_EXIT. We can however still
	 * get a few PERF_RECORD_READ events.
	 */
	perf_event_task(child, child_ctx, 0);

	list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
		perf_event_exit_event(child_event, child_ctx, child);

	mutex_unlock(&child_ctx->mutex);

	put_ctx(child_ctx);
}

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.