[Bug] 多线程操作rt_device_open和rt_device_close同一个设备，可能会使ref_count错误变化 #11234
Description
RT-Thread Version
master
Hardware Type/Architectures
Cortex-M4
Develop Toolchain
IAR
Describe the bug
rt_err_t rt_device_open(rt_device_t dev, rt_uint16_t oflag)
{
...
/* set open flag */
if (result == RT_EOK || result == -RT_ENOSYS)
{
dev->open_flag |= RT_DEVICE_OFLAG_OPEN;
dev->ref_count++;
/* don't let bad things happen silently. If you are bitten by this assert,
* please set the ref_count to a bigger type. */
RT_ASSERT(dev->ref_count != 0);
}
return result;
}
rt_err_t rt_device_close(rt_device_t dev)
{
...
if (dev->ref_count == 0)
return -RT_ERROR;
dev->ref_count--;
if (dev->ref_count != 0)
return RT_EOK;
...
return result;
}
从rt_device_open和rt_device_close源码来看，对ref_count++和--是非原子操作，在多线程操作同一个设备时ref_count可能会不按预期变化。
实际在使用过程中，在open时有概率会进入RT_ASSERT(dev->ref_count != 0);
Other additional context
No response