Go语言模拟内核进程通信：单通道正常，新增释放通道后死锁求助

我是Go channels的新手，正在通过构建模拟内核与进程的通道交互来学习Go通道。本示例程序的目标是让多个进程（2个）通过单个通道同时向内核发送内存分配请求，其他进程通过另一个单独的通道发送内存释放请求。

+-------------+
                           +------------------+       |             |
                          -> Alloc. Mem. Ch.  |<--\   |             |
+-----------------+   ---/ +------------------+   >-->|   Kernel    |
|   Process A     |<--     +------------------+ -/    |             |
+-----------------+   \--> |  Release Mem. Ch. |<      |             |
                           +------------------+       +-------------+

当仅保留内存分配请求时程序可正常运行，但一旦引入内存释放请求，程序就会陷入死锁。

注：进程在发送分配请求时还会创建一个回复队列，但因不属于问题范畴未在图中展示。

完整程序代码 #

package main

import (
        "fmt"
        // "log"
        "time"
)

const (
        _ float64 = iota
        LowPrio
        MedPrio
        HghPrio
)

// Kernel type to communicate between processes and memory resources
type Kernel struct {
        reqMemCh chan chan int
        rlsMemCh chan int
}

func (k *Kernel) Init() {
        k.reqMemCh = make(chan chan int, 2)
        k.rlsMemCh = make(chan int, 2)
        go k.AllocMem()
        go k.RlsMem()
}

// Fetch memory on process request
func (k *Kernel) GetReqMemCh() chan chan int {
        return k.reqMemCh
}

func (k *Kernel) GetRlsMemCh() chan int {
        return k.rlsMemCh
}

func (k *Kernel) AllocMem() {
        // loop over the items (process reply channels) received over
        // the request channel
        for pCh := range k.GetReqMemCh() {
                // for now think 0 is the available index
                // send this as a reply to the exclusive process reply channel
                pCh <- 0
                close(pCh)
        }
}

// Release memory
func (k *Kernel) RlsMem() {
        // we do not have to anything here
}

// Process type which requests memory
type Proc struct {
        ind     int
        prio    float64
        exeT    time.Time
        count   int
        memInd  int
        rqMemCh chan chan int
        rlMemCh chan int
}

func (p *Proc) Init(
        ind int,
        prio float64,
        rqMemCh chan chan int,
        rlMemCh chan int,
) {
        p.ind = ind
        p.prio = prio
        p.memInd = -1
        p.rqMemCh = rqMemCh
        p.rlMemCh = rlMemCh
}

func (p *Proc) GetReqMemCh() chan chan int {
        return p.rqMemCh
}

func (p *Proc) GetRlsMemCh() chan int {
        return p.rlMemCh
}

func (p *Proc) ReqMem() {
        // create the reply channel exclusive to the process
        // this channel will return the allocated memeory id/address
        rpCh := make(chan int)
        // send the reply channel through the request channel
        // to get back the allocation memory id
        p.GetReqMemCh() <- rpCh
        // Below line is blocking ...
        for mi := range rpCh {
                p.memInd = mi
        }
}

func (p Proc) RlsMem() {
        p.GetRlsMemCh() <- 0
}

func (p Proc) String() string {
        return fmt.Sprintf(
                "Proc(%d): Memory(%d), Count(%d)",
                p.ind+1, p.memInd+1, p.count,
        )
}

func main() {

        k := &Kernel{}
        k.Init()

        p := &Proc{}
        for i := 0; i < 3; i++ {
                p.Init(i, LowPrio, k.GetReqMemCh(), k.GetRlsMemCh())
                p.ReqMem()
                p.RlsMem()
        }

        time.Sleep(time.Second)
}

程序抛出的异常信息 #

fatal error: all goroutines are asleep - deadlock!

goroutine 1 [chan send]:
main.Proc.RlsMem(...)
        main.go:100
main.main()
        main.go:119 +0xc5

goroutine 6 [chan receive]:
main.(*Kernel).AllocMem(0x0?)
        main.go:41 +0x5e
created by main.(*Kernel).Init in goroutine 1
        main.go:25 +0xc5
exit status 2

恳请各位提供帮助，谢谢！

内容的提问来源于stack exchange，提问作者DDStackoverflow