void __init fork_init(void)
{
	int i;
#ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
#ifndef ARCH_MIN_TASKALIGN
#define ARCH_MIN_TASKALIGN	0
#endif
	int align = max_t(int, L1_CACHE_BYTES, ARCH_MIN_TASKALIGN);

	/* create a slab on which task_structs can be allocated */
	task_struct_cachep = kmem_cache_create("task_struct",
			arch_task_struct_size, align,
			SLAB_PANIC|SLAB_NOTRACK|SLAB_ACCOUNT, NULL);
#endif

	/* do the arch specific task caches init */
	arch_task_cache_init();

	set_max_threads(MAX_THREADS);

	init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
	init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
	init_task.signal->rlim[RLIMIT_SIGPENDING] =
		init_task.signal->rlim[RLIMIT_NPROC];

	for (i = 0; i < UCOUNT_COUNTS; i++) {
		init_user_ns.ucount_max[i] = max_threads/2;
	}

#ifdef CONFIG_VMAP_STACK
	cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "fork:vm_stack_cache",
			  NULL, free_vm_stack_cache);
#endif
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.