为什么STM32移植LWIP程序中执行lwip_comm_init后创建信号量会失败？

移植lwip很久了,总是提示:
Assertion "failed to create mem_mutex" failed at line 302 in ..SRCLwiplwip-1.4.1srccoremem.c
Assertion "OSQCreate" failed at line 66 in ..SRCLwiparchsys_arch.c
Assertion "failed to create tcpip_thread mbox" failed at line 462 in ..SRCLwiplwip-1.4.1srcapitcpip.c
创建信号量和邮箱失败
后来发现:
在lwip_comm_init之前创建信号量或邮箱均OK,但是执行完lwip_comm_init后创建信号量或邮箱就失败,返回NULL,lwip_comm_mem_malloc申请内存没问题OK,请问下大神,是哪里出问题了???