int is_valid_bugaddr(unsigned long addr)
{
	unsigned short ud;

	if (addr < TASK_SIZE_MAX)
		return 0;

	if (probe_kernel_address((unsigned short *)addr, ud))
		return 0;

	return ud == INSN_UD0 || ud == INSN_UD2;
}

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.